view gcc/cp/parser.c @ 16:04ced10e8804

gcc 7
author kono
date Fri, 27 Oct 2017 22:46:09 +0900
parents
children 84e7813d76e9
line wrap: on
line source

/* -*- C++ -*- Parser.
   Copyright (C) 2000-2017 Free Software Foundation, Inc.
   Written by Mark Mitchell <mark@codesourcery.com>.

   This file is part of GCC.

   GCC is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3, or (at your option)
   any later version.

   GCC is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "cp-tree.h"
#include "c-family/c-common.h"
#include "timevar.h"
#include "stringpool.h"
#include "cgraph.h"
#include "print-tree.h"
#include "attribs.h"
#include "trans-mem.h"
#include "intl.h"
#include "decl.h"
#include "c-family/c-objc.h"
#include "plugin.h"
#include "tree-pretty-print.h"
#include "parser.h"
#include "gomp-constants.h"
#include "omp-general.h"
#include "omp-offload.h"
#include "c-family/c-indentation.h"
#include "context.h"
#include "cp-cilkplus.h"
#include "gcc-rich-location.h"
#include "tree-iterator.h"


/* The lexer.  */

/* The cp_lexer_* routines mediate between the lexer proper (in libcpp
   and c-lex.c) and the C++ parser.  */

static cp_token eof_token =
{
  CPP_EOF, RID_MAX, 0, false, false, false, 0, { NULL }
};

/* The various kinds of non integral constant we encounter. */
enum non_integral_constant {
  NIC_NONE,
  /* floating-point literal */
  NIC_FLOAT,
  /* %<this%> */
  NIC_THIS,
  /* %<__FUNCTION__%> */
  NIC_FUNC_NAME,
  /* %<__PRETTY_FUNCTION__%> */
  NIC_PRETTY_FUNC,
  /* %<__func__%> */
  NIC_C99_FUNC,
  /* "%<va_arg%> */
  NIC_VA_ARG,
  /* a cast */
  NIC_CAST,
  /* %<typeid%> operator */
  NIC_TYPEID,
  /* non-constant compound literals */
  NIC_NCC,
  /* a function call */
  NIC_FUNC_CALL,
  /* an increment */
  NIC_INC,
  /* an decrement */
  NIC_DEC,
  /* an array reference */
  NIC_ARRAY_REF,
  /* %<->%> */
  NIC_ARROW,
  /* %<.%> */
  NIC_POINT,
  /* the address of a label */
  NIC_ADDR_LABEL,
  /* %<*%> */
  NIC_STAR,
  /* %<&%> */
  NIC_ADDR,
  /* %<++%> */
  NIC_PREINCREMENT,
  /* %<--%> */
  NIC_PREDECREMENT,
  /* %<new%> */
  NIC_NEW,
  /* %<delete%> */
  NIC_DEL,
  /* calls to overloaded operators */
  NIC_OVERLOADED,
  /* an assignment */
  NIC_ASSIGNMENT,
  /* a comma operator */
  NIC_COMMA,
  /* a call to a constructor */
  NIC_CONSTRUCTOR,
  /* a transaction expression */
  NIC_TRANSACTION
};

/* The various kinds of errors about name-lookup failing. */
enum name_lookup_error {
  /* NULL */
  NLE_NULL,
  /* is not a type */
  NLE_TYPE,
  /* is not a class or namespace */
  NLE_CXX98,
  /* is not a class, namespace, or enumeration */
  NLE_NOT_CXX98
};

/* The various kinds of required token */
enum required_token {
  RT_NONE,
  RT_SEMICOLON,  /* ';' */
  RT_OPEN_PAREN, /* '(' */
  RT_CLOSE_BRACE, /* '}' */
  RT_OPEN_BRACE,  /* '{' */
  RT_CLOSE_SQUARE, /* ']' */
  RT_OPEN_SQUARE,  /* '[' */
  RT_COMMA, /* ',' */
  RT_SCOPE, /* '::' */
  RT_LESS, /* '<' */
  RT_GREATER, /* '>' */
  RT_EQ, /* '=' */
  RT_ELLIPSIS, /* '...' */
  RT_MULT, /* '*' */
  RT_COMPL, /* '~' */
  RT_COLON, /* ':' */
  RT_COLON_SCOPE, /* ':' or '::' */
  RT_CLOSE_PAREN, /* ')' */
  RT_COMMA_CLOSE_PAREN, /* ',' or ')' */
  RT_PRAGMA_EOL, /* end of line */
  RT_NAME, /* identifier */

  /* The type is CPP_KEYWORD */
  RT_NEW, /* new */
  RT_DELETE, /* delete */
  RT_RETURN, /* return */
  RT_WHILE, /* while */
  RT_EXTERN, /* extern */
  RT_STATIC_ASSERT, /* static_assert */
  RT_DECLTYPE, /* decltype */
  RT_OPERATOR, /* operator */
  RT_CLASS, /* class */
  RT_TEMPLATE, /* template */
  RT_NAMESPACE, /* namespace */
  RT_USING, /* using */
  RT_ASM, /* asm */
  RT_TRY, /* try */
  RT_CATCH, /* catch */
  RT_THROW, /* throw */
  RT_LABEL, /* __label__ */
  RT_AT_TRY, /* @try */
  RT_AT_SYNCHRONIZED, /* @synchronized */
  RT_AT_THROW, /* @throw */

  RT_SELECT,  /* selection-statement */
  RT_ITERATION, /* iteration-statement */
  RT_JUMP, /* jump-statement */
  RT_CLASS_KEY, /* class-key */
  RT_CLASS_TYPENAME_TEMPLATE, /* class, typename, or template */
  RT_TRANSACTION_ATOMIC, /* __transaction_atomic */
  RT_TRANSACTION_RELAXED, /* __transaction_relaxed */
  RT_TRANSACTION_CANCEL /* __transaction_cancel */
};

/* RAII wrapper for parser->in_type_id_in_expr_p, setting it on creation and
   reverting it on destruction.  */

class type_id_in_expr_sentinel
{
  cp_parser *parser;
  bool saved;
public:
  type_id_in_expr_sentinel (cp_parser *parser, bool set = true)
    : parser (parser),
      saved (parser->in_type_id_in_expr_p)
  { parser->in_type_id_in_expr_p = set; }
  ~type_id_in_expr_sentinel ()
  { parser->in_type_id_in_expr_p = saved; }
};

/* Prototypes.  */

static cp_lexer *cp_lexer_new_main
  (void);
static cp_lexer *cp_lexer_new_from_tokens
  (cp_token_cache *tokens);
static void cp_lexer_destroy
  (cp_lexer *);
static int cp_lexer_saving_tokens
  (const cp_lexer *);
static cp_token *cp_lexer_token_at
  (cp_lexer *, cp_token_position);
static void cp_lexer_get_preprocessor_token
  (cp_lexer *, cp_token *);
static inline cp_token *cp_lexer_peek_token
  (cp_lexer *);
static cp_token *cp_lexer_peek_nth_token
  (cp_lexer *, size_t);
static inline bool cp_lexer_next_token_is
  (cp_lexer *, enum cpp_ttype);
static bool cp_lexer_next_token_is_not
  (cp_lexer *, enum cpp_ttype);
static bool cp_lexer_next_token_is_keyword
  (cp_lexer *, enum rid);
static cp_token *cp_lexer_consume_token
  (cp_lexer *);
static void cp_lexer_purge_token
  (cp_lexer *);
static void cp_lexer_purge_tokens_after
  (cp_lexer *, cp_token_position);
static void cp_lexer_save_tokens
  (cp_lexer *);
static void cp_lexer_commit_tokens
  (cp_lexer *);
static void cp_lexer_rollback_tokens
  (cp_lexer *);
static void cp_lexer_print_token
  (FILE *, cp_token *);
static inline bool cp_lexer_debugging_p
  (cp_lexer *);
static void cp_lexer_start_debugging
  (cp_lexer *) ATTRIBUTE_UNUSED;
static void cp_lexer_stop_debugging
  (cp_lexer *) ATTRIBUTE_UNUSED;

static cp_token_cache *cp_token_cache_new
  (cp_token *, cp_token *);

static void cp_parser_initial_pragma
  (cp_token *);

static void cp_parser_cilk_simd
  (cp_parser *, cp_token *, bool *);
static tree cp_parser_cilk_for
  (cp_parser *, tree, bool *);
static bool cp_parser_omp_declare_reduction_exprs
  (tree, cp_parser *);
static tree cp_parser_cilk_simd_vectorlength 
  (cp_parser *, tree, bool);
static void cp_finalize_oacc_routine
  (cp_parser *, tree, bool);

/* Manifest constants.  */
#define CP_LEXER_BUFFER_SIZE ((256 * 1024) / sizeof (cp_token))
#define CP_SAVED_TOKEN_STACK 5

/* Variables.  */

/* The stream to which debugging output should be written.  */
static FILE *cp_lexer_debug_stream;

/* Nonzero if we are parsing an unevaluated operand: an operand to
   sizeof, typeof, or alignof.  */
int cp_unevaluated_operand;

/* Dump up to NUM tokens in BUFFER to FILE starting with token
   START_TOKEN.  If START_TOKEN is NULL, the dump starts with the
   first token in BUFFER.  If NUM is 0, dump all the tokens.  If
   CURR_TOKEN is set and it is one of the tokens in BUFFER, it will be
   highlighted by surrounding it in [[ ]].  */

static void
cp_lexer_dump_tokens (FILE *file, vec<cp_token, va_gc> *buffer,
		      cp_token *start_token, unsigned num,
		      cp_token *curr_token)
{
  unsigned i, nprinted;
  cp_token *token;
  bool do_print;

  fprintf (file, "%u tokens\n", vec_safe_length (buffer));

  if (buffer == NULL)
    return;

  if (num == 0)
    num = buffer->length ();

  if (start_token == NULL)
    start_token = buffer->address ();

  if (start_token > buffer->address ())
    {
      cp_lexer_print_token (file, &(*buffer)[0]);
      fprintf (file, " ... ");
    }

  do_print = false;
  nprinted = 0;
  for (i = 0; buffer->iterate (i, &token) && nprinted < num; i++)
    {
      if (token == start_token)
	do_print = true;

      if (!do_print)
	continue;

      nprinted++;
      if (token == curr_token)
	fprintf (file, "[[");

      cp_lexer_print_token (file, token);

      if (token == curr_token)
	fprintf (file, "]]");

      switch (token->type)
	{
	  case CPP_SEMICOLON:
	  case CPP_OPEN_BRACE:
	  case CPP_CLOSE_BRACE:
	  case CPP_EOF:
	    fputc ('\n', file);
	    break;

	  default:
	    fputc (' ', file);
	}
    }

  if (i == num && i < buffer->length ())
    {
      fprintf (file, " ... ");
      cp_lexer_print_token (file, &buffer->last ());
    }

  fprintf (file, "\n");
}


/* Dump all tokens in BUFFER to stderr.  */

void
cp_lexer_debug_tokens (vec<cp_token, va_gc> *buffer)
{
  cp_lexer_dump_tokens (stderr, buffer, NULL, 0, NULL);
}

DEBUG_FUNCTION void
debug (vec<cp_token, va_gc> &ref)
{
  cp_lexer_dump_tokens (stderr, &ref, NULL, 0, NULL);
}

DEBUG_FUNCTION void
debug (vec<cp_token, va_gc> *ptr)
{
  if (ptr)
    debug (*ptr);
  else
    fprintf (stderr, "<nil>\n");
}


/* Dump the cp_parser tree field T to FILE if T is non-NULL.  DESC is the
   description for T.  */

static void
cp_debug_print_tree_if_set (FILE *file, const char *desc, tree t)
{
  if (t)
    {
      fprintf (file, "%s: ", desc);
      print_node_brief (file, "", t, 0);
    }
}


/* Dump parser context C to FILE.  */

static void
cp_debug_print_context (FILE *file, cp_parser_context *c)
{
  const char *status_s[] = { "OK", "ERROR", "COMMITTED" };
  fprintf (file, "{ status = %s, scope = ", status_s[c->status]);
  print_node_brief (file, "", c->object_type, 0);
  fprintf (file, "}\n");
}


/* Print the stack of parsing contexts to FILE starting with FIRST.  */

static void
cp_debug_print_context_stack (FILE *file, cp_parser_context *first)
{
  unsigned i;
  cp_parser_context *c;

  fprintf (file, "Parsing context stack:\n");
  for (i = 0, c = first; c; c = c->next, i++)
    {
      fprintf (file, "\t#%u: ", i);
      cp_debug_print_context (file, c);
    }
}


/* Print the value of FLAG to FILE.  DESC is a string describing the flag.  */

static void
cp_debug_print_flag (FILE *file, const char *desc, bool flag)
{
  if (flag)
    fprintf (file, "%s: true\n", desc);
}


/* Print an unparsed function entry UF to FILE.  */

static void
cp_debug_print_unparsed_function (FILE *file, cp_unparsed_functions_entry *uf)
{
  unsigned i;
  cp_default_arg_entry *default_arg_fn;
  tree fn;

  fprintf (file, "\tFunctions with default args:\n");
  for (i = 0;
       vec_safe_iterate (uf->funs_with_default_args, i, &default_arg_fn);
       i++)
    {
      fprintf (file, "\t\tClass type: ");
      print_node_brief (file, "", default_arg_fn->class_type, 0);
      fprintf (file, "\t\tDeclaration: ");
      print_node_brief (file, "", default_arg_fn->decl, 0);
      fprintf (file, "\n");
    }

  fprintf (file, "\n\tFunctions with definitions that require "
	   "post-processing\n\t\t");
  for (i = 0; vec_safe_iterate (uf->funs_with_definitions, i, &fn); i++)
    {
      print_node_brief (file, "", fn, 0);
      fprintf (file, " ");
    }
  fprintf (file, "\n");

  fprintf (file, "\n\tNon-static data members with initializers that require "
           "post-processing\n\t\t");
  for (i = 0; vec_safe_iterate (uf->nsdmis, i, &fn); i++)
    {
      print_node_brief (file, "", fn, 0);
      fprintf (file, " ");
    }
  fprintf (file, "\n");
}


/* Print the stack of unparsed member functions S to FILE.  */

static void
cp_debug_print_unparsed_queues (FILE *file,
				vec<cp_unparsed_functions_entry, va_gc> *s)
{
  unsigned i;
  cp_unparsed_functions_entry *uf;

  fprintf (file, "Unparsed functions\n");
  for (i = 0; vec_safe_iterate (s, i, &uf); i++)
    {
      fprintf (file, "#%u:\n", i);
      cp_debug_print_unparsed_function (file, uf);
    }
}


/* Dump the tokens in a window of size WINDOW_SIZE around the next_token for
   the given PARSER.  If FILE is NULL, the output is printed on stderr. */

static void
cp_debug_parser_tokens (FILE *file, cp_parser *parser, int window_size)
{
  cp_token *next_token, *first_token, *start_token;

  if (file == NULL)
    file = stderr;

  next_token = parser->lexer->next_token;
  first_token = parser->lexer->buffer->address ();
  start_token = (next_token > first_token + window_size / 2)
		? next_token - window_size / 2
		: first_token;
  cp_lexer_dump_tokens (file, parser->lexer->buffer, start_token, window_size,
			next_token);
}


/* Dump debugging information for the given PARSER.  If FILE is NULL,
   the output is printed on stderr.  */

void
cp_debug_parser (FILE *file, cp_parser *parser)
{
  const size_t window_size = 20;
  cp_token *token;
  expanded_location eloc;

  if (file == NULL)
    file = stderr;

  fprintf (file, "Parser state\n\n");
  fprintf (file, "Number of tokens: %u\n",
	   vec_safe_length (parser->lexer->buffer));
  cp_debug_print_tree_if_set (file, "Lookup scope", parser->scope);
  cp_debug_print_tree_if_set (file, "Object scope",
				     parser->object_scope);
  cp_debug_print_tree_if_set (file, "Qualifying scope",
				     parser->qualifying_scope);
  cp_debug_print_context_stack (file, parser->context);
  cp_debug_print_flag (file, "Allow GNU extensions",
			      parser->allow_gnu_extensions_p);
  cp_debug_print_flag (file, "'>' token is greater-than",
			      parser->greater_than_is_operator_p);
  cp_debug_print_flag (file, "Default args allowed in current "
			      "parameter list", parser->default_arg_ok_p);
  cp_debug_print_flag (file, "Parsing integral constant-expression",
			      parser->integral_constant_expression_p);
  cp_debug_print_flag (file, "Allow non-constant expression in current "
			      "constant-expression",
			      parser->allow_non_integral_constant_expression_p);
  cp_debug_print_flag (file, "Seen non-constant expression",
			      parser->non_integral_constant_expression_p);
  cp_debug_print_flag (file, "Local names and 'this' forbidden in "
			      "current context",
			      parser->local_variables_forbidden_p);
  cp_debug_print_flag (file, "In unbraced linkage specification",
			      parser->in_unbraced_linkage_specification_p);
  cp_debug_print_flag (file, "Parsing a declarator",
			      parser->in_declarator_p);
  cp_debug_print_flag (file, "In template argument list",
			      parser->in_template_argument_list_p);
  cp_debug_print_flag (file, "Parsing an iteration statement",
			      parser->in_statement & IN_ITERATION_STMT);
  cp_debug_print_flag (file, "Parsing a switch statement",
			      parser->in_statement & IN_SWITCH_STMT);
  cp_debug_print_flag (file, "Parsing a structured OpenMP block",
			      parser->in_statement & IN_OMP_BLOCK);
  cp_debug_print_flag (file, "Parsing a Cilk Plus for loop",
			      parser->in_statement & IN_CILK_SIMD_FOR);
  cp_debug_print_flag (file, "Parsing a an OpenMP loop",
			      parser->in_statement & IN_OMP_FOR);
  cp_debug_print_flag (file, "Parsing an if statement",
			      parser->in_statement & IN_IF_STMT);
  cp_debug_print_flag (file, "Parsing a type-id in an expression "
			      "context", parser->in_type_id_in_expr_p);
  cp_debug_print_flag (file, "Declarations are implicitly extern \"C\"",
			      parser->implicit_extern_c);
  cp_debug_print_flag (file, "String expressions should be translated "
			      "to execution character set",
			      parser->translate_strings_p);
  cp_debug_print_flag (file, "Parsing function body outside of a "
			      "local class", parser->in_function_body);
  cp_debug_print_flag (file, "Auto correct a colon to a scope operator",
			      parser->colon_corrects_to_scope_p);
  cp_debug_print_flag (file, "Colon doesn't start a class definition",
			      parser->colon_doesnt_start_class_def_p);
  if (parser->type_definition_forbidden_message)
    fprintf (file, "Error message for forbidden type definitions: %s\n",
	     parser->type_definition_forbidden_message);
  cp_debug_print_unparsed_queues (file, parser->unparsed_queues);
  fprintf (file, "Number of class definitions in progress: %u\n",
	   parser->num_classes_being_defined);
  fprintf (file, "Number of template parameter lists for the current "
	   "declaration: %u\n", parser->num_template_parameter_lists);
  cp_debug_parser_tokens (file, parser, window_size);
  token = parser->lexer->next_token;
  fprintf (file, "Next token to parse:\n");
  fprintf (file, "\tToken:  ");
  cp_lexer_print_token (file, token);
  eloc = expand_location (token->location);
  fprintf (file, "\n\tFile:   %s\n", eloc.file);
  fprintf (file, "\tLine:   %d\n", eloc.line);
  fprintf (file, "\tColumn: %d\n", eloc.column);
}

DEBUG_FUNCTION void
debug (cp_parser &ref)
{
  cp_debug_parser (stderr, &ref);
}

DEBUG_FUNCTION void
debug (cp_parser *ptr)
{
  if (ptr)
    debug (*ptr);
  else
    fprintf (stderr, "<nil>\n");
}

/* Allocate memory for a new lexer object and return it.  */

static cp_lexer *
cp_lexer_alloc (void)
{
  cp_lexer *lexer;

  c_common_no_more_pch ();

  /* Allocate the memory.  */
  lexer = ggc_cleared_alloc<cp_lexer> ();

  /* Initially we are not debugging.  */
  lexer->debugging_p = false;

  lexer->saved_tokens.create (CP_SAVED_TOKEN_STACK);

  /* Create the buffer.  */
  vec_alloc (lexer->buffer, CP_LEXER_BUFFER_SIZE);

  return lexer;
}


/* Create a new main C++ lexer, the lexer that gets tokens from the
   preprocessor.  */

static cp_lexer *
cp_lexer_new_main (void)
{
  cp_lexer *lexer;
  cp_token token;

  /* It's possible that parsing the first pragma will load a PCH file,
     which is a GC collection point.  So we have to do that before
     allocating any memory.  */
  cp_parser_initial_pragma (&token);

  lexer = cp_lexer_alloc ();

  /* Put the first token in the buffer.  */
  lexer->buffer->quick_push (token);

  /* Get the remaining tokens from the preprocessor.  */
  while (token.type != CPP_EOF)
    {
      cp_lexer_get_preprocessor_token (lexer, &token);
      vec_safe_push (lexer->buffer, token);
    }

  lexer->last_token = lexer->buffer->address ()
                      + lexer->buffer->length ()
		      - 1;
  lexer->next_token = lexer->buffer->length ()
		      ? lexer->buffer->address ()
		      : &eof_token;

  /* Subsequent preprocessor diagnostics should use compiler
     diagnostic functions to get the compiler source location.  */
  done_lexing = true;

  gcc_assert (!lexer->next_token->purged_p);
  return lexer;
}

/* Create a new lexer whose token stream is primed with the tokens in
   CACHE.  When these tokens are exhausted, no new tokens will be read.  */

static cp_lexer *
cp_lexer_new_from_tokens (cp_token_cache *cache)
{
  cp_token *first = cache->first;
  cp_token *last = cache->last;
  cp_lexer *lexer = ggc_cleared_alloc<cp_lexer> ();

  /* We do not own the buffer.  */
  lexer->buffer = NULL;
  lexer->next_token = first == last ? &eof_token : first;
  lexer->last_token = last;

  lexer->saved_tokens.create (CP_SAVED_TOKEN_STACK);

  /* Initially we are not debugging.  */
  lexer->debugging_p = false;

  gcc_assert (!lexer->next_token->purged_p);
  return lexer;
}

/* Frees all resources associated with LEXER.  */

static void
cp_lexer_destroy (cp_lexer *lexer)
{
  vec_free (lexer->buffer);
  lexer->saved_tokens.release ();
  ggc_free (lexer);
}

/* This needs to be set to TRUE before the lexer-debugging infrastructure can
   be used.  The point of this flag is to help the compiler to fold away calls
   to cp_lexer_debugging_p within this source file at compile time, when the
   lexer is not being debugged.  */

#define LEXER_DEBUGGING_ENABLED_P false

/* Returns nonzero if debugging information should be output.  */

static inline bool
cp_lexer_debugging_p (cp_lexer *lexer)
{
  if (!LEXER_DEBUGGING_ENABLED_P)
    return false;

  return lexer->debugging_p;
}


static inline cp_token_position
cp_lexer_token_position (cp_lexer *lexer, bool previous_p)
{
  gcc_assert (!previous_p || lexer->next_token != &eof_token);

  return lexer->next_token - previous_p;
}

static inline cp_token *
cp_lexer_token_at (cp_lexer * /*lexer*/, cp_token_position pos)
{
  return pos;
}

static inline void
cp_lexer_set_token_position (cp_lexer *lexer, cp_token_position pos)
{
  lexer->next_token = cp_lexer_token_at (lexer, pos);
}

static inline cp_token_position
cp_lexer_previous_token_position (cp_lexer *lexer)
{
  if (lexer->next_token == &eof_token)
    return lexer->last_token - 1;
  else
    return cp_lexer_token_position (lexer, true);
}

static inline cp_token *
cp_lexer_previous_token (cp_lexer *lexer)
{
  cp_token_position tp = cp_lexer_previous_token_position (lexer);

  /* Skip past purged tokens.  */
  while (tp->purged_p)
    {
      gcc_assert (tp != vec_safe_address (lexer->buffer));
      tp--;
    }

  return cp_lexer_token_at (lexer, tp);
}

/* nonzero if we are presently saving tokens.  */

static inline int
cp_lexer_saving_tokens (const cp_lexer* lexer)
{
  return lexer->saved_tokens.length () != 0;
}

/* Store the next token from the preprocessor in *TOKEN.  Return true
   if we reach EOF.  If LEXER is NULL, assume we are handling an
   initial #pragma pch_preprocess, and thus want the lexer to return
   processed strings.  */

static void
cp_lexer_get_preprocessor_token (cp_lexer *lexer, cp_token *token)
{
  static int is_extern_c = 0;

   /* Get a new token from the preprocessor.  */
  token->type
    = c_lex_with_flags (&token->u.value, &token->location, &token->flags,
			lexer == NULL ? 0 : C_LEX_STRING_NO_JOIN);
  token->keyword = RID_MAX;
  token->purged_p = false;
  token->error_reported = false;

  /* On some systems, some header files are surrounded by an
     implicit extern "C" block.  Set a flag in the token if it
     comes from such a header.  */
  is_extern_c += pending_lang_change;
  pending_lang_change = 0;
  token->implicit_extern_c = is_extern_c > 0;

  /* Check to see if this token is a keyword.  */
  if (token->type == CPP_NAME)
    {
      if (IDENTIFIER_KEYWORD_P (token->u.value))
	{
	  /* Mark this token as a keyword.  */
	  token->type = CPP_KEYWORD;
	  /* Record which keyword.  */
	  token->keyword = C_RID_CODE (token->u.value);
	}
      else
	{
          if (warn_cxx11_compat
              && C_RID_CODE (token->u.value) >= RID_FIRST_CXX11
              && C_RID_CODE (token->u.value) <= RID_LAST_CXX11)
            {
              /* Warn about the C++0x keyword (but still treat it as
                 an identifier).  */
              warning (OPT_Wc__11_compat, 
                       "identifier %qE is a keyword in C++11",
                       token->u.value);

              /* Clear out the C_RID_CODE so we don't warn about this
                 particular identifier-turned-keyword again.  */
              C_SET_RID_CODE (token->u.value, RID_MAX);
            }

	  token->keyword = RID_MAX;
	}
    }
  else if (token->type == CPP_AT_NAME)
    {
      /* This only happens in Objective-C++; it must be a keyword.  */
      token->type = CPP_KEYWORD;
      switch (C_RID_CODE (token->u.value))
	{
	  /* Replace 'class' with '@class', 'private' with '@private',
	     etc.  This prevents confusion with the C++ keyword
	     'class', and makes the tokens consistent with other
	     Objective-C 'AT' keywords.  For example '@class' is
	     reported as RID_AT_CLASS which is consistent with
	     '@synchronized', which is reported as
	     RID_AT_SYNCHRONIZED.
	  */
	case RID_CLASS:     token->keyword = RID_AT_CLASS; break;
	case RID_PRIVATE:   token->keyword = RID_AT_PRIVATE; break;
	case RID_PROTECTED: token->keyword = RID_AT_PROTECTED; break;
	case RID_PUBLIC:    token->keyword = RID_AT_PUBLIC; break;
	case RID_THROW:     token->keyword = RID_AT_THROW; break;
	case RID_TRY:       token->keyword = RID_AT_TRY; break;
	case RID_CATCH:     token->keyword = RID_AT_CATCH; break;
	case RID_SYNCHRONIZED: token->keyword = RID_AT_SYNCHRONIZED; break;
	default:            token->keyword = C_RID_CODE (token->u.value);
	}
    }
}

/* Update the globals input_location and the input file stack from TOKEN.  */
static inline void
cp_lexer_set_source_position_from_token (cp_token *token)
{
  if (token->type != CPP_EOF)
    {
      input_location = token->location;
    }
}

/* Update the globals input_location and the input file stack from LEXER.  */
static inline void
cp_lexer_set_source_position (cp_lexer *lexer)
{
  cp_token *token = cp_lexer_peek_token (lexer);
  cp_lexer_set_source_position_from_token (token);
}

/* Return a pointer to the next token in the token stream, but do not
   consume it.  */

static inline cp_token *
cp_lexer_peek_token (cp_lexer *lexer)
{
  if (cp_lexer_debugging_p (lexer))
    {
      fputs ("cp_lexer: peeking at token: ", cp_lexer_debug_stream);
      cp_lexer_print_token (cp_lexer_debug_stream, lexer->next_token);
      putc ('\n', cp_lexer_debug_stream);
    }
  return lexer->next_token;
}

/* Return true if the next token has the indicated TYPE.  */

static inline bool
cp_lexer_next_token_is (cp_lexer* lexer, enum cpp_ttype type)
{
  return cp_lexer_peek_token (lexer)->type == type;
}

/* Return true if the next token does not have the indicated TYPE.  */

static inline bool
cp_lexer_next_token_is_not (cp_lexer* lexer, enum cpp_ttype type)
{
  return !cp_lexer_next_token_is (lexer, type);
}

/* Return true if the next token is the indicated KEYWORD.  */

static inline bool
cp_lexer_next_token_is_keyword (cp_lexer* lexer, enum rid keyword)
{
  return cp_lexer_peek_token (lexer)->keyword == keyword;
}

static inline bool
cp_lexer_nth_token_is (cp_lexer* lexer, size_t n, enum cpp_ttype type)
{
  return cp_lexer_peek_nth_token (lexer, n)->type == type;
}

static inline bool
cp_lexer_nth_token_is_keyword (cp_lexer* lexer, size_t n, enum rid keyword)
{
  return cp_lexer_peek_nth_token (lexer, n)->keyword == keyword;
}

/* Return true if the next token is not the indicated KEYWORD.  */

static inline bool
cp_lexer_next_token_is_not_keyword (cp_lexer* lexer, enum rid keyword)
{
  return cp_lexer_peek_token (lexer)->keyword != keyword;
}

/* Return true if KEYWORD can start a decl-specifier.  */

bool
cp_keyword_starts_decl_specifier_p (enum rid keyword)
{
  switch (keyword)
    {
      /* auto specifier: storage-class-specifier in C++,
         simple-type-specifier in C++0x.  */
    case RID_AUTO:
      /* Storage classes.  */
    case RID_REGISTER:
    case RID_STATIC:
    case RID_EXTERN:
    case RID_MUTABLE:
    case RID_THREAD:
      /* Elaborated type specifiers.  */
    case RID_ENUM:
    case RID_CLASS:
    case RID_STRUCT:
    case RID_UNION:
    case RID_TYPENAME:
      /* Simple type specifiers.  */
    case RID_CHAR:
    case RID_CHAR16:
    case RID_CHAR32:
    case RID_WCHAR:
    case RID_BOOL:
    case RID_SHORT:
    case RID_INT:
    case RID_LONG:
    case RID_SIGNED:
    case RID_UNSIGNED:
    case RID_FLOAT:
    case RID_DOUBLE:
    case RID_VOID:
      /* GNU extensions.  */ 
    case RID_ATTRIBUTE:
    case RID_TYPEOF:
      /* C++0x extensions.  */
    case RID_DECLTYPE:
    case RID_UNDERLYING_TYPE:
    case RID_CONSTEXPR:
      return true;

    default:
      if (keyword >= RID_FIRST_INT_N
	  && keyword < RID_FIRST_INT_N + NUM_INT_N_ENTS
	  && int_n_enabled_p[keyword - RID_FIRST_INT_N])
	return true;
      return false;
    }
}

/* Return true if the next token is a keyword for a decl-specifier.  */

static bool
cp_lexer_next_token_is_decl_specifier_keyword (cp_lexer *lexer)
{
  cp_token *token;

  token = cp_lexer_peek_token (lexer);
  return cp_keyword_starts_decl_specifier_p (token->keyword);
}

/* Returns TRUE iff the token T begins a decltype type.  */

static bool
token_is_decltype (cp_token *t)
{
  return (t->keyword == RID_DECLTYPE
	  || t->type == CPP_DECLTYPE);
}

/* Returns TRUE iff the next token begins a decltype type.  */

static bool
cp_lexer_next_token_is_decltype (cp_lexer *lexer)
{
  cp_token *t = cp_lexer_peek_token (lexer);
  return token_is_decltype (t);
}

/* Called when processing a token with tree_check_value; perform or defer the
   associated checks and return the value.  */

static tree
saved_checks_value (struct tree_check *check_value)
{
  /* Perform any access checks that were deferred.  */
  vec<deferred_access_check, va_gc> *checks;
  deferred_access_check *chk;
  checks = check_value->checks;
  if (checks)
    {
      int i;
      FOR_EACH_VEC_SAFE_ELT (checks, i, chk)
	perform_or_defer_access_check (chk->binfo,
				       chk->decl,
				       chk->diag_decl, tf_warning_or_error);
    }
  /* Return the stored value.  */
  return check_value->value;
}

/* Return a pointer to the Nth token in the token stream.  If N is 1,
   then this is precisely equivalent to cp_lexer_peek_token (except
   that it is not inline).  One would like to disallow that case, but
   there is one case (cp_parser_nth_token_starts_template_id) where
   the caller passes a variable for N and it might be 1.  */

static cp_token *
cp_lexer_peek_nth_token (cp_lexer* lexer, size_t n)
{
  cp_token *token;

  /* N is 1-based, not zero-based.  */
  gcc_assert (n > 0);

  if (cp_lexer_debugging_p (lexer))
    fprintf (cp_lexer_debug_stream,
	     "cp_lexer: peeking ahead %ld at token: ", (long)n);

  --n;
  token = lexer->next_token;
  gcc_assert (!n || token != &eof_token);
  while (n != 0)
    {
      ++token;
      if (token == lexer->last_token)
	{
	  token = &eof_token;
	  break;
	}

      if (!token->purged_p)
	--n;
    }

  if (cp_lexer_debugging_p (lexer))
    {
      cp_lexer_print_token (cp_lexer_debug_stream, token);
      putc ('\n', cp_lexer_debug_stream);
    }

  return token;
}

/* Return the next token, and advance the lexer's next_token pointer
   to point to the next non-purged token.  */

static cp_token *
cp_lexer_consume_token (cp_lexer* lexer)
{
  cp_token *token = lexer->next_token;

  gcc_assert (token != &eof_token);
  gcc_assert (!lexer->in_pragma || token->type != CPP_PRAGMA_EOL);

  do
    {
      lexer->next_token++;
      if (lexer->next_token == lexer->last_token)
	{
	  lexer->next_token = &eof_token;
	  break;
	}

    }
  while (lexer->next_token->purged_p);

  cp_lexer_set_source_position_from_token (token);

  /* Provide debugging output.  */
  if (cp_lexer_debugging_p (lexer))
    {
      fputs ("cp_lexer: consuming token: ", cp_lexer_debug_stream);
      cp_lexer_print_token (cp_lexer_debug_stream, token);
      putc ('\n', cp_lexer_debug_stream);
    }

  return token;
}

/* Permanently remove the next token from the token stream, and
   advance the next_token pointer to refer to the next non-purged
   token.  */

static void
cp_lexer_purge_token (cp_lexer *lexer)
{
  cp_token *tok = lexer->next_token;

  gcc_assert (tok != &eof_token);
  tok->purged_p = true;
  tok->location = UNKNOWN_LOCATION;
  tok->u.value = NULL_TREE;
  tok->keyword = RID_MAX;

  do
    {
      tok++;
      if (tok == lexer->last_token)
	{
	  tok = &eof_token;
	  break;
	}
    }
  while (tok->purged_p);
  lexer->next_token = tok;
}

/* Permanently remove all tokens after TOK, up to, but not
   including, the token that will be returned next by
   cp_lexer_peek_token.  */

static void
cp_lexer_purge_tokens_after (cp_lexer *lexer, cp_token *tok)
{
  cp_token *peek = lexer->next_token;

  if (peek == &eof_token)
    peek = lexer->last_token;

  gcc_assert (tok < peek);

  for ( tok += 1; tok != peek; tok += 1)
    {
      tok->purged_p = true;
      tok->location = UNKNOWN_LOCATION;
      tok->u.value = NULL_TREE;
      tok->keyword = RID_MAX;
    }
}

/* Begin saving tokens.  All tokens consumed after this point will be
   preserved.  */

static void
cp_lexer_save_tokens (cp_lexer* lexer)
{
  /* Provide debugging output.  */
  if (cp_lexer_debugging_p (lexer))
    fprintf (cp_lexer_debug_stream, "cp_lexer: saving tokens\n");

  lexer->saved_tokens.safe_push (lexer->next_token);
}

/* Commit to the portion of the token stream most recently saved.  */

static void
cp_lexer_commit_tokens (cp_lexer* lexer)
{
  /* Provide debugging output.  */
  if (cp_lexer_debugging_p (lexer))
    fprintf (cp_lexer_debug_stream, "cp_lexer: committing tokens\n");

  lexer->saved_tokens.pop ();
}

/* Return all tokens saved since the last call to cp_lexer_save_tokens
   to the token stream.  Stop saving tokens.  */

static void
cp_lexer_rollback_tokens (cp_lexer* lexer)
{
  /* Provide debugging output.  */
  if (cp_lexer_debugging_p (lexer))
    fprintf (cp_lexer_debug_stream, "cp_lexer: restoring tokens\n");

  lexer->next_token = lexer->saved_tokens.pop ();
}

/* RAII wrapper around the above functions, with sanity checking.  Creating
   a variable saves tokens, which are committed when the variable is
   destroyed unless they are explicitly rolled back by calling the rollback
   member function.  */

struct saved_token_sentinel
{
  cp_lexer *lexer;
  unsigned len;
  bool commit;
  saved_token_sentinel(cp_lexer *lexer): lexer(lexer), commit(true)
  {
    len = lexer->saved_tokens.length ();
    cp_lexer_save_tokens (lexer);
  }
  void rollback ()
  {
    cp_lexer_rollback_tokens (lexer);
    commit = false;
  }
  ~saved_token_sentinel()
  {
    if (commit)
      cp_lexer_commit_tokens (lexer);
    gcc_assert (lexer->saved_tokens.length () == len);
  }
};

/* Print a representation of the TOKEN on the STREAM.  */

static void
cp_lexer_print_token (FILE * stream, cp_token *token)
{
  /* We don't use cpp_type2name here because the parser defines
     a few tokens of its own.  */
  static const char *const token_names[] = {
    /* cpplib-defined token types */
#define OP(e, s) #e,
#define TK(e, s) #e,
    TTYPE_TABLE
#undef OP
#undef TK
    /* C++ parser token types - see "Manifest constants", above.  */
    "KEYWORD",
    "TEMPLATE_ID",
    "NESTED_NAME_SPECIFIER",
  };

  /* For some tokens, print the associated data.  */
  switch (token->type)
    {
    case CPP_KEYWORD:
      /* Some keywords have a value that is not an IDENTIFIER_NODE.
	 For example, `struct' is mapped to an INTEGER_CST.  */
      if (!identifier_p (token->u.value))
	break;
      /* fall through */
    case CPP_NAME:
      fputs (IDENTIFIER_POINTER (token->u.value), stream);
      break;

    case CPP_STRING:
    case CPP_STRING16:
    case CPP_STRING32:
    case CPP_WSTRING:
    case CPP_UTF8STRING:
      fprintf (stream, " \"%s\"", TREE_STRING_POINTER (token->u.value));
      break;

    case CPP_NUMBER:
      print_generic_expr (stream, token->u.value);
      break;

    default:
      /* If we have a name for the token, print it out.  Otherwise, we
	 simply give the numeric code.  */
      if (token->type < ARRAY_SIZE(token_names))
	fputs (token_names[token->type], stream);
      else
	fprintf (stream, "[%d]", token->type);
      break;
    }
}

DEBUG_FUNCTION void
debug (cp_token &ref)
{
  cp_lexer_print_token (stderr, &ref);
  fprintf (stderr, "\n");
}

DEBUG_FUNCTION void
debug (cp_token *ptr)
{
  if (ptr)
    debug (*ptr);
  else
    fprintf (stderr, "<nil>\n");
}


/* Start emitting debugging information.  */

static void
cp_lexer_start_debugging (cp_lexer* lexer)
{
  if (!LEXER_DEBUGGING_ENABLED_P)
    fatal_error (input_location,
		 "LEXER_DEBUGGING_ENABLED_P is not set to true");

  lexer->debugging_p = true;
  cp_lexer_debug_stream = stderr;
}

/* Stop emitting debugging information.  */

static void
cp_lexer_stop_debugging (cp_lexer* lexer)
{
  if (!LEXER_DEBUGGING_ENABLED_P)
    fatal_error (input_location,
		 "LEXER_DEBUGGING_ENABLED_P is not set to true");

  lexer->debugging_p = false;
  cp_lexer_debug_stream = NULL;
}

/* Create a new cp_token_cache, representing a range of tokens.  */

static cp_token_cache *
cp_token_cache_new (cp_token *first, cp_token *last)
{
  cp_token_cache *cache = ggc_alloc<cp_token_cache> ();
  cache->first = first;
  cache->last = last;
  return cache;
}

/* Diagnose if #pragma omp declare simd isn't followed immediately
   by function declaration or definition.  */

static inline void
cp_ensure_no_omp_declare_simd (cp_parser *parser)
{
  if (parser->omp_declare_simd && !parser->omp_declare_simd->error_seen)
    {
      error ("%<#pragma omp declare simd%> not immediately followed by "
	     "function declaration or definition");
      parser->omp_declare_simd = NULL;
    }
}

/* Finalize #pragma omp declare simd clauses after FNDECL has been parsed,
   and put that into "omp declare simd" attribute.  */

static inline void
cp_finalize_omp_declare_simd (cp_parser *parser, tree fndecl)
{
  if (__builtin_expect (parser->omp_declare_simd != NULL, 0))
    {
      if (fndecl == error_mark_node)
	{
	  parser->omp_declare_simd = NULL;
	  return;
	}
      if (TREE_CODE (fndecl) != FUNCTION_DECL)
	{
	  cp_ensure_no_omp_declare_simd (parser);
	  return;
	}
    }
}

/* Diagnose if #pragma acc routine isn't followed immediately by function
   declaration or definition.  */

static inline void
cp_ensure_no_oacc_routine (cp_parser *parser)
{
  if (parser->oacc_routine && !parser->oacc_routine->error_seen)
    {
      error_at (parser->oacc_routine->loc,
		"%<#pragma acc routine%> not immediately followed by "
		"function declaration or definition");
      parser->oacc_routine = NULL;
    }
}

/* Decl-specifiers.  */

/* Set *DECL_SPECS to represent an empty decl-specifier-seq.  */

static void
clear_decl_specs (cp_decl_specifier_seq *decl_specs)
{
  memset (decl_specs, 0, sizeof (cp_decl_specifier_seq));
}

/* Declarators.  */

/* Nothing other than the parser should be creating declarators;
   declarators are a semi-syntactic representation of C++ entities.
   Other parts of the front end that need to create entities (like
   VAR_DECLs or FUNCTION_DECLs) should do that directly.  */

static cp_declarator *make_call_declarator
  (cp_declarator *, tree, cp_cv_quals, cp_virt_specifiers, cp_ref_qualifier, tree, tree, tree, tree);
static cp_declarator *make_array_declarator
  (cp_declarator *, tree);
static cp_declarator *make_pointer_declarator
  (cp_cv_quals, cp_declarator *, tree);
static cp_declarator *make_reference_declarator
  (cp_cv_quals, cp_declarator *, bool, tree);
static cp_declarator *make_ptrmem_declarator
  (cp_cv_quals, tree, cp_declarator *, tree);

/* An erroneous declarator.  */
static cp_declarator *cp_error_declarator;

/* The obstack on which declarators and related data structures are
   allocated.  */
static struct obstack declarator_obstack;

/* Alloc BYTES from the declarator memory pool.  */

static inline void *
alloc_declarator (size_t bytes)
{
  return obstack_alloc (&declarator_obstack, bytes);
}

/* Allocate a declarator of the indicated KIND.  Clear fields that are
   common to all declarators.  */

static cp_declarator *
make_declarator (cp_declarator_kind kind)
{
  cp_declarator *declarator;

  declarator = (cp_declarator *) alloc_declarator (sizeof (cp_declarator));
  declarator->kind = kind;
  declarator->parenthesized = UNKNOWN_LOCATION;
  declarator->attributes = NULL_TREE;
  declarator->std_attributes = NULL_TREE;
  declarator->declarator = NULL;
  declarator->parameter_pack_p = false;
  declarator->id_loc = UNKNOWN_LOCATION;

  return declarator;
}

/* Make a declarator for a generalized identifier.  If
   QUALIFYING_SCOPE is non-NULL, the identifier is
   QUALIFYING_SCOPE::UNQUALIFIED_NAME; otherwise, it is just
   UNQUALIFIED_NAME.  SFK indicates the kind of special function this
   is, if any.   */

static cp_declarator *
make_id_declarator (tree qualifying_scope, tree unqualified_name,
		    special_function_kind sfk)
{
  cp_declarator *declarator;

  /* It is valid to write:

       class C { void f(); };
       typedef C D;
       void D::f();

     The standard is not clear about whether `typedef const C D' is
     legal; as of 2002-09-15 the committee is considering that
     question.  EDG 3.0 allows that syntax.  Therefore, we do as
     well.  */
  if (qualifying_scope && TYPE_P (qualifying_scope))
    qualifying_scope = TYPE_MAIN_VARIANT (qualifying_scope);

  gcc_assert (identifier_p (unqualified_name)
	      || TREE_CODE (unqualified_name) == BIT_NOT_EXPR
	      || TREE_CODE (unqualified_name) == TEMPLATE_ID_EXPR);

  declarator = make_declarator (cdk_id);
  declarator->u.id.qualifying_scope = qualifying_scope;
  declarator->u.id.unqualified_name = unqualified_name;
  declarator->u.id.sfk = sfk;
  
  return declarator;
}

/* Make a declarator for a pointer to TARGET.  CV_QUALIFIERS is a list
   of modifiers such as const or volatile to apply to the pointer
   type, represented as identifiers.  ATTRIBUTES represent the attributes that
   appertain to the pointer or reference.  */

cp_declarator *
make_pointer_declarator (cp_cv_quals cv_qualifiers, cp_declarator *target,
			 tree attributes)
{
  cp_declarator *declarator;

  declarator = make_declarator (cdk_pointer);
  declarator->declarator = target;
  declarator->u.pointer.qualifiers = cv_qualifiers;
  declarator->u.pointer.class_type = NULL_TREE;
  if (target)
    {
      declarator->id_loc = target->id_loc;
      declarator->parameter_pack_p = target->parameter_pack_p;
      target->parameter_pack_p = false;
    }
  else
    declarator->parameter_pack_p = false;

  declarator->std_attributes = attributes;

  return declarator;
}

/* Like make_pointer_declarator -- but for references.  ATTRIBUTES
   represent the attributes that appertain to the pointer or
   reference.  */

cp_declarator *
make_reference_declarator (cp_cv_quals cv_qualifiers, cp_declarator *target,
			   bool rvalue_ref, tree attributes)
{
  cp_declarator *declarator;

  declarator = make_declarator (cdk_reference);
  declarator->declarator = target;
  declarator->u.reference.qualifiers = cv_qualifiers;
  declarator->u.reference.rvalue_ref = rvalue_ref;
  if (target)
    {
      declarator->id_loc = target->id_loc;
      declarator->parameter_pack_p = target->parameter_pack_p;
      target->parameter_pack_p = false;
    }
  else
    declarator->parameter_pack_p = false;

  declarator->std_attributes = attributes;

  return declarator;
}

/* Like make_pointer_declarator -- but for a pointer to a non-static
   member of CLASS_TYPE.  ATTRIBUTES represent the attributes that
   appertain to the pointer or reference.  */

cp_declarator *
make_ptrmem_declarator (cp_cv_quals cv_qualifiers, tree class_type,
			cp_declarator *pointee,
			tree attributes)
{
  cp_declarator *declarator;

  declarator = make_declarator (cdk_ptrmem);
  declarator->declarator = pointee;
  declarator->u.pointer.qualifiers = cv_qualifiers;
  declarator->u.pointer.class_type = class_type;

  if (pointee)
    {
      declarator->parameter_pack_p = pointee->parameter_pack_p;
      pointee->parameter_pack_p = false;
    }
  else
    declarator->parameter_pack_p = false;

  declarator->std_attributes = attributes;

  return declarator;
}

/* Make a declarator for the function given by TARGET, with the
   indicated PARMS.  The CV_QUALIFIERS apply to the function, as in
   "const"-qualified member function.  The EXCEPTION_SPECIFICATION
   indicates what exceptions can be thrown.  */

cp_declarator *
make_call_declarator (cp_declarator *target,
		      tree parms,
		      cp_cv_quals cv_qualifiers,
		      cp_virt_specifiers virt_specifiers,
		      cp_ref_qualifier ref_qualifier,
		      tree tx_qualifier,
		      tree exception_specification,
		      tree late_return_type,
		      tree requires_clause)
{
  cp_declarator *declarator;

  declarator = make_declarator (cdk_function);
  declarator->declarator = target;
  declarator->u.function.parameters = parms;
  declarator->u.function.qualifiers = cv_qualifiers;
  declarator->u.function.virt_specifiers = virt_specifiers;
  declarator->u.function.ref_qualifier = ref_qualifier;
  declarator->u.function.tx_qualifier = tx_qualifier;
  declarator->u.function.exception_specification = exception_specification;
  declarator->u.function.late_return_type = late_return_type;
  declarator->u.function.requires_clause = requires_clause;
  if (target)
    {
      declarator->id_loc = target->id_loc;
      declarator->parameter_pack_p = target->parameter_pack_p;
      target->parameter_pack_p = false;
    }
  else
    declarator->parameter_pack_p = false;

  return declarator;
}

/* Make a declarator for an array of BOUNDS elements, each of which is
   defined by ELEMENT.  */

cp_declarator *
make_array_declarator (cp_declarator *element, tree bounds)
{
  cp_declarator *declarator;

  declarator = make_declarator (cdk_array);
  declarator->declarator = element;
  declarator->u.array.bounds = bounds;
  if (element)
    {
      declarator->id_loc = element->id_loc;
      declarator->parameter_pack_p = element->parameter_pack_p;
      element->parameter_pack_p = false;
    }
  else
    declarator->parameter_pack_p = false;

  return declarator;
}

/* Determine whether the declarator we've seen so far can be a
   parameter pack, when followed by an ellipsis.  */
static bool 
declarator_can_be_parameter_pack (cp_declarator *declarator)
{
  if (declarator && declarator->parameter_pack_p)
    /* We already saw an ellipsis.  */
    return false;

  /* Search for a declarator name, or any other declarator that goes
     after the point where the ellipsis could appear in a parameter
     pack. If we find any of these, then this declarator can not be
     made into a parameter pack.  */
  bool found = false;
  while (declarator && !found)
    {
      switch ((int)declarator->kind)
	{
	case cdk_id:
	case cdk_array:
	case cdk_decomp:
	  found = true;
	  break;

	case cdk_error:
	  return true;

	default:
	  declarator = declarator->declarator;
	  break;
	}
    }

  return !found;
}

cp_parameter_declarator *no_parameters;

/* Create a parameter declarator with the indicated DECL_SPECIFIERS,
   DECLARATOR and DEFAULT_ARGUMENT.  */

cp_parameter_declarator *
make_parameter_declarator (cp_decl_specifier_seq *decl_specifiers,
			   cp_declarator *declarator,
			   tree default_argument,
			   location_t loc,
			   bool template_parameter_pack_p = false)
{
  cp_parameter_declarator *parameter;

  parameter = ((cp_parameter_declarator *)
	       alloc_declarator (sizeof (cp_parameter_declarator)));
  parameter->next = NULL;
  if (decl_specifiers)
    parameter->decl_specifiers = *decl_specifiers;
  else
    clear_decl_specs (&parameter->decl_specifiers);
  parameter->declarator = declarator;
  parameter->default_argument = default_argument;
  parameter->template_parameter_pack_p = template_parameter_pack_p;
  parameter->loc = loc;

  return parameter;
}

/* Returns true iff DECLARATOR  is a declaration for a function.  */

static bool
function_declarator_p (const cp_declarator *declarator)
{
  while (declarator)
    {
      if (declarator->kind == cdk_function
	  && declarator->declarator->kind == cdk_id)
	return true;
      if (declarator->kind == cdk_id
	  || declarator->kind == cdk_decomp
	  || declarator->kind == cdk_error)
	return false;
      declarator = declarator->declarator;
    }
  return false;
}
 
/* The parser.  */

/* Overview
   --------

   A cp_parser parses the token stream as specified by the C++
   grammar.  Its job is purely parsing, not semantic analysis.  For
   example, the parser breaks the token stream into declarators,
   expressions, statements, and other similar syntactic constructs.
   It does not check that the types of the expressions on either side
   of an assignment-statement are compatible, or that a function is
   not declared with a parameter of type `void'.

   The parser invokes routines elsewhere in the compiler to perform
   semantic analysis and to build up the abstract syntax tree for the
   code processed.

   The parser (and the template instantiation code, which is, in a
   way, a close relative of parsing) are the only parts of the
   compiler that should be calling push_scope and pop_scope, or
   related functions.  The parser (and template instantiation code)
   keeps track of what scope is presently active; everything else
   should simply honor that.  (The code that generates static
   initializers may also need to set the scope, in order to check
   access control correctly when emitting the initializers.)

   Methodology
   -----------

   The parser is of the standard recursive-descent variety.  Upcoming
   tokens in the token stream are examined in order to determine which
   production to use when parsing a non-terminal.  Some C++ constructs
   require arbitrary look ahead to disambiguate.  For example, it is
   impossible, in the general case, to tell whether a statement is an
   expression or declaration without scanning the entire statement.
   Therefore, the parser is capable of "parsing tentatively."  When the
   parser is not sure what construct comes next, it enters this mode.
   Then, while we attempt to parse the construct, the parser queues up
   error messages, rather than issuing them immediately, and saves the
   tokens it consumes.  If the construct is parsed successfully, the
   parser "commits", i.e., it issues any queued error messages and
   the tokens that were being preserved are permanently discarded.
   If, however, the construct is not parsed successfully, the parser
   rolls back its state completely so that it can resume parsing using
   a different alternative.

   Future Improvements
   -------------------

   The performance of the parser could probably be improved substantially.
   We could often eliminate the need to parse tentatively by looking ahead
   a little bit.  In some places, this approach might not entirely eliminate
   the need to parse tentatively, but it might still speed up the average
   case.  */

/* Flags that are passed to some parsing functions.  These values can
   be bitwise-ored together.  */

enum
{
  /* No flags.  */
  CP_PARSER_FLAGS_NONE = 0x0,
  /* The construct is optional.  If it is not present, then no error
     should be issued.  */
  CP_PARSER_FLAGS_OPTIONAL = 0x1,
  /* When parsing a type-specifier, treat user-defined type-names
     as non-type identifiers.  */
  CP_PARSER_FLAGS_NO_USER_DEFINED_TYPES = 0x2,
  /* When parsing a type-specifier, do not try to parse a class-specifier
     or enum-specifier.  */
  CP_PARSER_FLAGS_NO_TYPE_DEFINITIONS = 0x4,
  /* When parsing a decl-specifier-seq, only allow type-specifier or
     constexpr.  */
  CP_PARSER_FLAGS_ONLY_TYPE_OR_CONSTEXPR = 0x8,
  /* When parsing a decl-specifier-seq, only allow mutable or constexpr.  */
  CP_PARSER_FLAGS_ONLY_MUTABLE_OR_CONSTEXPR = 0x10
};

/* This type is used for parameters and variables which hold
   combinations of the above flags.  */
typedef int cp_parser_flags;

/* The different kinds of declarators we want to parse.  */

enum cp_parser_declarator_kind
{
  /* We want an abstract declarator.  */
  CP_PARSER_DECLARATOR_ABSTRACT,
  /* We want a named declarator.  */
  CP_PARSER_DECLARATOR_NAMED,
  /* We don't mind, but the name must be an unqualified-id.  */
  CP_PARSER_DECLARATOR_EITHER
};

/* The precedence values used to parse binary expressions.  The minimum value
   of PREC must be 1, because zero is reserved to quickly discriminate
   binary operators from other tokens.  */

enum cp_parser_prec
{
  PREC_NOT_OPERATOR,
  PREC_LOGICAL_OR_EXPRESSION,
  PREC_LOGICAL_AND_EXPRESSION,
  PREC_INCLUSIVE_OR_EXPRESSION,
  PREC_EXCLUSIVE_OR_EXPRESSION,
  PREC_AND_EXPRESSION,
  PREC_EQUALITY_EXPRESSION,
  PREC_RELATIONAL_EXPRESSION,
  PREC_SHIFT_EXPRESSION,
  PREC_ADDITIVE_EXPRESSION,
  PREC_MULTIPLICATIVE_EXPRESSION,
  PREC_PM_EXPRESSION,
  NUM_PREC_VALUES = PREC_PM_EXPRESSION
};

/* A mapping from a token type to a corresponding tree node type, with a
   precedence value.  */

struct cp_parser_binary_operations_map_node
{
  /* The token type.  */
  enum cpp_ttype token_type;
  /* The corresponding tree code.  */
  enum tree_code tree_type;
  /* The precedence of this operator.  */
  enum cp_parser_prec prec;
};

struct cp_parser_expression_stack_entry
{
  /* Left hand side of the binary operation we are currently
     parsing.  */
  cp_expr lhs;
  /* Original tree code for left hand side, if it was a binary
     expression itself (used for -Wparentheses).  */
  enum tree_code lhs_type;
  /* Tree code for the binary operation we are parsing.  */
  enum tree_code tree_type;
  /* Precedence of the binary operation we are parsing.  */
  enum cp_parser_prec prec;
  /* Location of the binary operation we are parsing.  */
  location_t loc;
};

/* The stack for storing partial expressions.  We only need NUM_PREC_VALUES
   entries because precedence levels on the stack are monotonically
   increasing.  */
typedef struct cp_parser_expression_stack_entry
  cp_parser_expression_stack[NUM_PREC_VALUES];

/* Prototypes.  */

/* Constructors and destructors.  */

static cp_parser_context *cp_parser_context_new
  (cp_parser_context *);

/* Class variables.  */

static GTY((deletable)) cp_parser_context* cp_parser_context_free_list;

/* The operator-precedence table used by cp_parser_binary_expression.
   Transformed into an associative array (binops_by_token) by
   cp_parser_new.  */

static const cp_parser_binary_operations_map_node binops[] = {
  { CPP_DEREF_STAR, MEMBER_REF, PREC_PM_EXPRESSION },
  { CPP_DOT_STAR, DOTSTAR_EXPR, PREC_PM_EXPRESSION },

  { CPP_MULT, MULT_EXPR, PREC_MULTIPLICATIVE_EXPRESSION },
  { CPP_DIV, TRUNC_DIV_EXPR, PREC_MULTIPLICATIVE_EXPRESSION },
  { CPP_MOD, TRUNC_MOD_EXPR, PREC_MULTIPLICATIVE_EXPRESSION },

  { CPP_PLUS, PLUS_EXPR, PREC_ADDITIVE_EXPRESSION },
  { CPP_MINUS, MINUS_EXPR, PREC_ADDITIVE_EXPRESSION },

  { CPP_LSHIFT, LSHIFT_EXPR, PREC_SHIFT_EXPRESSION },
  { CPP_RSHIFT, RSHIFT_EXPR, PREC_SHIFT_EXPRESSION },

  { CPP_LESS, LT_EXPR, PREC_RELATIONAL_EXPRESSION },
  { CPP_GREATER, GT_EXPR, PREC_RELATIONAL_EXPRESSION },
  { CPP_LESS_EQ, LE_EXPR, PREC_RELATIONAL_EXPRESSION },
  { CPP_GREATER_EQ, GE_EXPR, PREC_RELATIONAL_EXPRESSION },

  { CPP_EQ_EQ, EQ_EXPR, PREC_EQUALITY_EXPRESSION },
  { CPP_NOT_EQ, NE_EXPR, PREC_EQUALITY_EXPRESSION },

  { CPP_AND, BIT_AND_EXPR, PREC_AND_EXPRESSION },

  { CPP_XOR, BIT_XOR_EXPR, PREC_EXCLUSIVE_OR_EXPRESSION },

  { CPP_OR, BIT_IOR_EXPR, PREC_INCLUSIVE_OR_EXPRESSION },

  { CPP_AND_AND, TRUTH_ANDIF_EXPR, PREC_LOGICAL_AND_EXPRESSION },

  { CPP_OR_OR, TRUTH_ORIF_EXPR, PREC_LOGICAL_OR_EXPRESSION }
};

/* The same as binops, but initialized by cp_parser_new so that
   binops_by_token[N].token_type == N.  Used in cp_parser_binary_expression
   for speed.  */
static cp_parser_binary_operations_map_node binops_by_token[N_CP_TTYPES];

/* Constructors and destructors.  */

/* Construct a new context.  The context below this one on the stack
   is given by NEXT.  */

static cp_parser_context *
cp_parser_context_new (cp_parser_context* next)
{
  cp_parser_context *context;

  /* Allocate the storage.  */
  if (cp_parser_context_free_list != NULL)
    {
      /* Pull the first entry from the free list.  */
      context = cp_parser_context_free_list;
      cp_parser_context_free_list = context->next;
      memset (context, 0, sizeof (*context));
    }
  else
    context = ggc_cleared_alloc<cp_parser_context> ();

  /* No errors have occurred yet in this context.  */
  context->status = CP_PARSER_STATUS_KIND_NO_ERROR;
  /* If this is not the bottommost context, copy information that we
     need from the previous context.  */
  if (next)
    {
      /* If, in the NEXT context, we are parsing an `x->' or `x.'
	 expression, then we are parsing one in this context, too.  */
      context->object_type = next->object_type;
      /* Thread the stack.  */
      context->next = next;
    }

  return context;
}

/* Managing the unparsed function queues.  */

#define unparsed_funs_with_default_args \
  parser->unparsed_queues->last ().funs_with_default_args
#define unparsed_funs_with_definitions \
  parser->unparsed_queues->last ().funs_with_definitions
#define unparsed_nsdmis \
  parser->unparsed_queues->last ().nsdmis
#define unparsed_classes \
  parser->unparsed_queues->last ().classes

static void
push_unparsed_function_queues (cp_parser *parser)
{
  cp_unparsed_functions_entry e = {NULL, make_tree_vector (), NULL, NULL};
  vec_safe_push (parser->unparsed_queues, e);
}

static void
pop_unparsed_function_queues (cp_parser *parser)
{
  release_tree_vector (unparsed_funs_with_definitions);
  parser->unparsed_queues->pop ();
}

/* Prototypes.  */

/* Constructors and destructors.  */

static cp_parser *cp_parser_new
  (void);

/* Routines to parse various constructs.

   Those that return `tree' will return the error_mark_node (rather
   than NULL_TREE) if a parse error occurs, unless otherwise noted.
   Sometimes, they will return an ordinary node if error-recovery was
   attempted, even though a parse error occurred.  So, to check
   whether or not a parse error occurred, you should always use
   cp_parser_error_occurred.  If the construct is optional (indicated
   either by an `_opt' in the name of the function that does the
   parsing or via a FLAGS parameter), then NULL_TREE is returned if
   the construct is not present.  */

/* Lexical conventions [gram.lex]  */

static cp_expr cp_parser_identifier
  (cp_parser *);
static cp_expr cp_parser_string_literal
  (cp_parser *, bool, bool, bool);
static cp_expr cp_parser_userdef_char_literal
  (cp_parser *);
static tree cp_parser_userdef_string_literal
  (tree);
static cp_expr cp_parser_userdef_numeric_literal
  (cp_parser *);

/* Basic concepts [gram.basic]  */

static bool cp_parser_translation_unit
  (cp_parser *);

/* Expressions [gram.expr]  */

static cp_expr cp_parser_primary_expression
  (cp_parser *, bool, bool, bool, cp_id_kind *);
static cp_expr cp_parser_id_expression
  (cp_parser *, bool, bool, bool *, bool, bool);
static cp_expr cp_parser_unqualified_id
  (cp_parser *, bool, bool, bool, bool);
static tree cp_parser_nested_name_specifier_opt
  (cp_parser *, bool, bool, bool, bool, bool = false);
static tree cp_parser_nested_name_specifier
  (cp_parser *, bool, bool, bool, bool);
static tree cp_parser_qualifying_entity
  (cp_parser *, bool, bool, bool, bool, bool);
static cp_expr cp_parser_postfix_expression
  (cp_parser *, bool, bool, bool, bool, cp_id_kind *);
static tree cp_parser_postfix_open_square_expression
  (cp_parser *, tree, bool, bool);
static tree cp_parser_postfix_dot_deref_expression
  (cp_parser *, enum cpp_ttype, cp_expr, bool, cp_id_kind *, location_t);
static vec<tree, va_gc> *cp_parser_parenthesized_expression_list
  (cp_parser *, int, bool, bool, bool *, location_t * = NULL);
/* Values for the second parameter of cp_parser_parenthesized_expression_list.  */
enum { non_attr = 0, normal_attr = 1, id_attr = 2 };
static void cp_parser_pseudo_destructor_name
  (cp_parser *, tree, tree *, tree *);
static cp_expr cp_parser_unary_expression
  (cp_parser *, cp_id_kind * = NULL, bool = false, bool = false, bool = false);
static enum tree_code cp_parser_unary_operator
  (cp_token *);
static tree cp_parser_new_expression
  (cp_parser *);
static vec<tree, va_gc> *cp_parser_new_placement
  (cp_parser *);
static tree cp_parser_new_type_id
  (cp_parser *, tree *);
static cp_declarator *cp_parser_new_declarator_opt
  (cp_parser *);
static cp_declarator *cp_parser_direct_new_declarator
  (cp_parser *);
static vec<tree, va_gc> *cp_parser_new_initializer
  (cp_parser *);
static tree cp_parser_delete_expression
  (cp_parser *);
static cp_expr cp_parser_cast_expression
  (cp_parser *, bool, bool, bool, cp_id_kind *);
static cp_expr cp_parser_binary_expression
  (cp_parser *, bool, bool, enum cp_parser_prec, cp_id_kind *);
static tree cp_parser_question_colon_clause
  (cp_parser *, cp_expr);
static cp_expr cp_parser_assignment_expression
  (cp_parser *, cp_id_kind * = NULL, bool = false, bool = false);
static enum tree_code cp_parser_assignment_operator_opt
  (cp_parser *);
static cp_expr cp_parser_expression
  (cp_parser *, cp_id_kind * = NULL, bool = false, bool = false);
static cp_expr cp_parser_constant_expression
  (cp_parser *, bool = false, bool * = NULL, bool = false);
static cp_expr cp_parser_builtin_offsetof
  (cp_parser *);
static cp_expr cp_parser_lambda_expression
  (cp_parser *);
static void cp_parser_lambda_introducer
  (cp_parser *, tree);
static bool cp_parser_lambda_declarator_opt
  (cp_parser *, tree);
static void cp_parser_lambda_body
  (cp_parser *, tree);

/* Statements [gram.stmt.stmt]  */

static void cp_parser_statement
  (cp_parser *, tree, bool, bool *, vec<tree> * = NULL, location_t * = NULL);
static void cp_parser_label_for_labeled_statement
(cp_parser *, tree);
static tree cp_parser_expression_statement
  (cp_parser *, tree);
static tree cp_parser_compound_statement
  (cp_parser *, tree, int, bool);
static void cp_parser_statement_seq_opt
  (cp_parser *, tree);
static tree cp_parser_selection_statement
  (cp_parser *, bool *, vec<tree> *);
static tree cp_parser_condition
  (cp_parser *);
static tree cp_parser_iteration_statement
  (cp_parser *, bool *, bool);
static bool cp_parser_init_statement
  (cp_parser *, tree *decl);
static tree cp_parser_for
  (cp_parser *, bool);
static tree cp_parser_c_for
  (cp_parser *, tree, tree, bool);
static tree cp_parser_range_for
  (cp_parser *, tree, tree, tree, bool);
static void do_range_for_auto_deduction
  (tree, tree);
static tree cp_parser_perform_range_for_lookup
  (tree, tree *, tree *);
static tree cp_parser_range_for_member_function
  (tree, tree);
static tree cp_parser_jump_statement
  (cp_parser *);
static void cp_parser_declaration_statement
  (cp_parser *);

static tree cp_parser_implicitly_scoped_statement
  (cp_parser *, bool *, const token_indent_info &, vec<tree> * = NULL);
static void cp_parser_already_scoped_statement
  (cp_parser *, bool *, const token_indent_info &);

/* Declarations [gram.dcl.dcl] */

static void cp_parser_declaration_seq_opt
  (cp_parser *);
static void cp_parser_declaration
  (cp_parser *);
static void cp_parser_block_declaration
  (cp_parser *, bool);
static void cp_parser_simple_declaration
  (cp_parser *, bool, tree *);
static void cp_parser_decl_specifier_seq
  (cp_parser *, cp_parser_flags, cp_decl_specifier_seq *, int *);
static tree cp_parser_storage_class_specifier_opt
  (cp_parser *);
static tree cp_parser_function_specifier_opt
  (cp_parser *, cp_decl_specifier_seq *);
static tree cp_parser_type_specifier
  (cp_parser *, cp_parser_flags, cp_decl_specifier_seq *, bool,
   int *, bool *);
static tree cp_parser_simple_type_specifier
  (cp_parser *, cp_decl_specifier_seq *, cp_parser_flags);
static tree cp_parser_type_name
  (cp_parser *, bool);
static tree cp_parser_type_name
  (cp_parser *);
static tree cp_parser_nonclass_name 
  (cp_parser* parser);
static tree cp_parser_elaborated_type_specifier
  (cp_parser *, bool, bool);
static tree cp_parser_enum_specifier
  (cp_parser *);
static void cp_parser_enumerator_list
  (cp_parser *, tree);
static void cp_parser_enumerator_definition
  (cp_parser *, tree);
static tree cp_parser_namespace_name
  (cp_parser *);
static void cp_parser_namespace_definition
  (cp_parser *);
static void cp_parser_namespace_body
  (cp_parser *);
static tree cp_parser_qualified_namespace_specifier
  (cp_parser *);
static void cp_parser_namespace_alias_definition
  (cp_parser *);
static bool cp_parser_using_declaration
  (cp_parser *, bool);
static void cp_parser_using_directive
  (cp_parser *);
static tree cp_parser_alias_declaration
  (cp_parser *);
static void cp_parser_asm_definition
  (cp_parser *);
static void cp_parser_linkage_specification
  (cp_parser *);
static void cp_parser_static_assert
  (cp_parser *, bool);
static tree cp_parser_decltype
  (cp_parser *);
static tree cp_parser_decomposition_declaration
  (cp_parser *, cp_decl_specifier_seq *, tree *, location_t *);

/* Declarators [gram.dcl.decl] */

static tree cp_parser_init_declarator
  (cp_parser *, cp_decl_specifier_seq *, vec<deferred_access_check, va_gc> *,
   bool, bool, int, bool *, tree *, location_t *, tree *);
static cp_declarator *cp_parser_declarator
  (cp_parser *, cp_parser_declarator_kind, int *, bool *, bool, bool);
static cp_declarator *cp_parser_direct_declarator
  (cp_parser *, cp_parser_declarator_kind, int *, bool, bool);
static enum tree_code cp_parser_ptr_operator
  (cp_parser *, tree *, cp_cv_quals *, tree *);
static cp_cv_quals cp_parser_cv_qualifier_seq_opt
  (cp_parser *);
static cp_virt_specifiers cp_parser_virt_specifier_seq_opt
  (cp_parser *);
static cp_ref_qualifier cp_parser_ref_qualifier_opt
  (cp_parser *);
static tree cp_parser_tx_qualifier_opt
  (cp_parser *);
static tree cp_parser_late_return_type_opt
  (cp_parser *, cp_declarator *, tree &, cp_cv_quals);
static tree cp_parser_declarator_id
  (cp_parser *, bool);
static tree cp_parser_type_id
  (cp_parser *);
static tree cp_parser_template_type_arg
  (cp_parser *);
static tree cp_parser_trailing_type_id (cp_parser *);
static tree cp_parser_type_id_1
  (cp_parser *, bool, bool);
static void cp_parser_type_specifier_seq
  (cp_parser *, bool, bool, cp_decl_specifier_seq *);
static tree cp_parser_parameter_declaration_clause
  (cp_parser *);
static tree cp_parser_parameter_declaration_list
  (cp_parser *, bool *);
static cp_parameter_declarator *cp_parser_parameter_declaration
  (cp_parser *, bool, bool *);
static tree cp_parser_default_argument 
  (cp_parser *, bool);
static void cp_parser_function_body
  (cp_parser *, bool);
static tree cp_parser_initializer
  (cp_parser *, bool *, bool *);
static cp_expr cp_parser_initializer_clause
  (cp_parser *, bool *);
static cp_expr cp_parser_braced_list
  (cp_parser*, bool*);
static vec<constructor_elt, va_gc> *cp_parser_initializer_list
  (cp_parser *, bool *);

static void cp_parser_ctor_initializer_opt_and_function_body
  (cp_parser *, bool);

static tree cp_parser_late_parsing_omp_declare_simd
  (cp_parser *, tree);

static tree cp_parser_late_parsing_cilk_simd_fn_info
  (cp_parser *, tree);

static tree cp_parser_late_parsing_oacc_routine
  (cp_parser *, tree);

static tree synthesize_implicit_template_parm
  (cp_parser *, tree);
static tree finish_fully_implicit_template
  (cp_parser *, tree);

/* Classes [gram.class] */

static tree cp_parser_class_name
  (cp_parser *, bool, bool, enum tag_types, bool, bool, bool, bool = false);
static tree cp_parser_class_specifier
  (cp_parser *);
static tree cp_parser_class_head
  (cp_parser *, bool *);
static enum tag_types cp_parser_class_key
  (cp_parser *);
static void cp_parser_type_parameter_key
  (cp_parser* parser);
static void cp_parser_member_specification_opt
  (cp_parser *);
static void cp_parser_member_declaration
  (cp_parser *);
static tree cp_parser_pure_specifier
  (cp_parser *);
static tree cp_parser_constant_initializer
  (cp_parser *);

/* Derived classes [gram.class.derived] */

static tree cp_parser_base_clause
  (cp_parser *);
static tree cp_parser_base_specifier
  (cp_parser *);

/* Special member functions [gram.special] */

static tree cp_parser_conversion_function_id
  (cp_parser *);
static tree cp_parser_conversion_type_id
  (cp_parser *);
static cp_declarator *cp_parser_conversion_declarator_opt
  (cp_parser *);
static void cp_parser_ctor_initializer_opt
  (cp_parser *);
static void cp_parser_mem_initializer_list
  (cp_parser *);
static tree cp_parser_mem_initializer
  (cp_parser *);
static tree cp_parser_mem_initializer_id
  (cp_parser *);

/* Overloading [gram.over] */

static cp_expr cp_parser_operator_function_id
  (cp_parser *);
static cp_expr cp_parser_operator
  (cp_parser *);

/* Templates [gram.temp] */

static void cp_parser_template_declaration
  (cp_parser *, bool);
static tree cp_parser_template_parameter_list
  (cp_parser *);
static tree cp_parser_template_parameter
  (cp_parser *, bool *, bool *);
static tree cp_parser_type_parameter
  (cp_parser *, bool *);
static tree cp_parser_template_id
  (cp_parser *, bool, bool, enum tag_types, bool);
static tree cp_parser_template_name
  (cp_parser *, bool, bool, bool, enum tag_types, bool *);
static tree cp_parser_template_argument_list
  (cp_parser *);
static tree cp_parser_template_argument
  (cp_parser *);
static void cp_parser_explicit_instantiation
  (cp_parser *);
static void cp_parser_explicit_specialization
  (cp_parser *);

/* Exception handling [gram.exception] */

static tree cp_parser_try_block
  (cp_parser *);
static void cp_parser_function_try_block
  (cp_parser *);
static void cp_parser_handler_seq
  (cp_parser *);
static void cp_parser_handler
  (cp_parser *);
static tree cp_parser_exception_declaration
  (cp_parser *);
static tree cp_parser_throw_expression
  (cp_parser *);
static tree cp_parser_exception_specification_opt
  (cp_parser *);
static tree cp_parser_type_id_list
  (cp_parser *);

/* GNU Extensions */

static tree cp_parser_asm_specification_opt
  (cp_parser *);
static tree cp_parser_asm_operand_list
  (cp_parser *);
static tree cp_parser_asm_clobber_list
  (cp_parser *);
static tree cp_parser_asm_label_list
  (cp_parser *);
static bool cp_next_tokens_can_be_attribute_p
  (cp_parser *);
static bool cp_next_tokens_can_be_gnu_attribute_p
  (cp_parser *);
static bool cp_next_tokens_can_be_std_attribute_p
  (cp_parser *);
static bool cp_nth_tokens_can_be_std_attribute_p
  (cp_parser *, size_t);
static bool cp_nth_tokens_can_be_gnu_attribute_p
  (cp_parser *, size_t);
static bool cp_nth_tokens_can_be_attribute_p
  (cp_parser *, size_t);
static tree cp_parser_attributes_opt
  (cp_parser *);
static tree cp_parser_gnu_attributes_opt
  (cp_parser *);
static tree cp_parser_gnu_attribute_list
  (cp_parser *);
static tree cp_parser_std_attribute
  (cp_parser *, tree);
static tree cp_parser_std_attribute_spec
  (cp_parser *);
static tree cp_parser_std_attribute_spec_seq
  (cp_parser *);
static bool cp_parser_extension_opt
  (cp_parser *, int *);
static void cp_parser_label_declaration
  (cp_parser *);

/* Concept Extensions */

static tree cp_parser_requires_clause
  (cp_parser *);
static tree cp_parser_requires_clause_opt
  (cp_parser *);
static tree cp_parser_requires_expression
  (cp_parser *);
static tree cp_parser_requirement_parameter_list
  (cp_parser *);
static tree cp_parser_requirement_body
  (cp_parser *);
static tree cp_parser_requirement_list
  (cp_parser *);
static tree cp_parser_requirement
  (cp_parser *);
static tree cp_parser_simple_requirement
  (cp_parser *);
static tree cp_parser_compound_requirement
  (cp_parser *);
static tree cp_parser_type_requirement
  (cp_parser *);
static tree cp_parser_nested_requirement
  (cp_parser *);

/* Transactional Memory Extensions */

static tree cp_parser_transaction
  (cp_parser *, cp_token *);
static tree cp_parser_transaction_expression
  (cp_parser *, enum rid);
static void cp_parser_function_transaction
  (cp_parser *, enum rid);
static tree cp_parser_transaction_cancel
  (cp_parser *);

enum pragma_context {
  pragma_external,
  pragma_member,
  pragma_objc_icode,
  pragma_stmt,
  pragma_compound
};
static bool cp_parser_pragma
  (cp_parser *, enum pragma_context, bool *);

/* Objective-C++ Productions */

static tree cp_parser_objc_message_receiver
  (cp_parser *);
static tree cp_parser_objc_message_args
  (cp_parser *);
static tree cp_parser_objc_message_expression
  (cp_parser *);
static cp_expr cp_parser_objc_encode_expression
  (cp_parser *);
static tree cp_parser_objc_defs_expression
  (cp_parser *);
static tree cp_parser_objc_protocol_expression
  (cp_parser *);
static tree cp_parser_objc_selector_expression
  (cp_parser *);
static cp_expr cp_parser_objc_expression
  (cp_parser *);
static bool cp_parser_objc_selector_p
  (enum cpp_ttype);
static tree cp_parser_objc_selector
  (cp_parser *);
static tree cp_parser_objc_protocol_refs_opt
  (cp_parser *);
static void cp_parser_objc_declaration
  (cp_parser *, tree);
static tree cp_parser_objc_statement
  (cp_parser *);
static bool cp_parser_objc_valid_prefix_attributes
  (cp_parser *, tree *);
static void cp_parser_objc_at_property_declaration 
  (cp_parser *) ;
static void cp_parser_objc_at_synthesize_declaration 
  (cp_parser *) ;
static void cp_parser_objc_at_dynamic_declaration
  (cp_parser *) ;
static tree cp_parser_objc_struct_declaration
  (cp_parser *) ;

/* Utility Routines */

static cp_expr cp_parser_lookup_name
  (cp_parser *, tree, enum tag_types, bool, bool, bool, tree *, location_t);
static tree cp_parser_lookup_name_simple
  (cp_parser *, tree, location_t);
static tree cp_parser_maybe_treat_template_as_class
  (tree, bool);
static bool cp_parser_check_declarator_template_parameters
  (cp_parser *, cp_declarator *, location_t);
static bool cp_parser_check_template_parameters
  (cp_parser *, unsigned, location_t, cp_declarator *);
static cp_expr cp_parser_simple_cast_expression
  (cp_parser *);
static tree cp_parser_global_scope_opt
  (cp_parser *, bool);
static bool cp_parser_constructor_declarator_p
  (cp_parser *, bool);
static tree cp_parser_function_definition_from_specifiers_and_declarator
  (cp_parser *, cp_decl_specifier_seq *, tree, const cp_declarator *);
static tree cp_parser_function_definition_after_declarator
  (cp_parser *, bool);
static bool cp_parser_template_declaration_after_export
  (cp_parser *, bool);
static void cp_parser_perform_template_parameter_access_checks
  (vec<deferred_access_check, va_gc> *);
static tree cp_parser_single_declaration
  (cp_parser *, vec<deferred_access_check, va_gc> *, bool, bool, bool *);
static cp_expr cp_parser_functional_cast
  (cp_parser *, tree);
static tree cp_parser_save_member_function_body
  (cp_parser *, cp_decl_specifier_seq *, cp_declarator *, tree);
static tree cp_parser_save_nsdmi
  (cp_parser *);
static tree cp_parser_enclosed_template_argument_list
  (cp_parser *);
static void cp_parser_save_default_args
  (cp_parser *, tree);
static void cp_parser_late_parsing_for_member
  (cp_parser *, tree);
static tree cp_parser_late_parse_one_default_arg
  (cp_parser *, tree, tree, tree);
static void cp_parser_late_parsing_nsdmi
  (cp_parser *, tree);
static void cp_parser_late_parsing_default_args
  (cp_parser *, tree);
static tree cp_parser_sizeof_operand
  (cp_parser *, enum rid);
static tree cp_parser_trait_expr
  (cp_parser *, enum rid);
static bool cp_parser_declares_only_class_p
  (cp_parser *);
static void cp_parser_set_storage_class
  (cp_parser *, cp_decl_specifier_seq *, enum rid, cp_token *);
static void cp_parser_set_decl_spec_type
  (cp_decl_specifier_seq *, tree, cp_token *, bool);
static void set_and_check_decl_spec_loc
  (cp_decl_specifier_seq *decl_specs,
   cp_decl_spec ds, cp_token *);
static bool cp_parser_friend_p
  (const cp_decl_specifier_seq *);
static void cp_parser_required_error
  (cp_parser *, required_token, bool, location_t);
static cp_token *cp_parser_require
  (cp_parser *, enum cpp_ttype, required_token, location_t = UNKNOWN_LOCATION);
static cp_token *cp_parser_require_keyword
  (cp_parser *, enum rid, required_token);
static bool cp_parser_token_starts_function_definition_p
  (cp_token *);
static bool cp_parser_next_token_starts_class_definition_p
  (cp_parser *);
static bool cp_parser_next_token_ends_template_argument_p
  (cp_parser *);
static bool cp_parser_nth_token_starts_template_argument_list_p
  (cp_parser *, size_t);
static enum tag_types cp_parser_token_is_class_key
  (cp_token *);
static enum tag_types cp_parser_token_is_type_parameter_key
  (cp_token *);
static void cp_parser_check_class_key
  (enum tag_types, tree type);
static void cp_parser_check_access_in_redeclaration
  (tree type, location_t location);
static bool cp_parser_optional_template_keyword
  (cp_parser *);
static void cp_parser_pre_parsed_nested_name_specifier
  (cp_parser *);
static bool cp_parser_cache_group
  (cp_parser *, enum cpp_ttype, unsigned);
static tree cp_parser_cache_defarg
  (cp_parser *parser, bool nsdmi);
static void cp_parser_parse_tentatively
  (cp_parser *);
static void cp_parser_commit_to_tentative_parse
  (cp_parser *);
static void cp_parser_commit_to_topmost_tentative_parse
  (cp_parser *);
static void cp_parser_abort_tentative_parse
  (cp_parser *);
static bool cp_parser_parse_definitely
  (cp_parser *);
static inline bool cp_parser_parsing_tentatively
  (cp_parser *);
static bool cp_parser_uncommitted_to_tentative_parse_p
  (cp_parser *);
static void cp_parser_error
  (cp_parser *, const char *);
static void cp_parser_name_lookup_error
  (cp_parser *, tree, tree, name_lookup_error, location_t);
static bool cp_parser_simulate_error
  (cp_parser *);
static bool cp_parser_check_type_definition
  (cp_parser *);
static void cp_parser_check_for_definition_in_return_type
  (cp_declarator *, tree, location_t type_location);
static void cp_parser_check_for_invalid_template_id
  (cp_parser *, tree, enum tag_types, location_t location);
static bool cp_parser_non_integral_constant_expression
  (cp_parser *, non_integral_constant);
static void cp_parser_diagnose_invalid_type_name
  (cp_parser *, tree, location_t);
static bool cp_parser_parse_and_diagnose_invalid_type_name
  (cp_parser *);
static int cp_parser_skip_to_closing_parenthesis
  (cp_parser *, bool, bool, bool);
static void cp_parser_skip_to_end_of_statement
  (cp_parser *);
static void cp_parser_consume_semicolon_at_end_of_statement
  (cp_parser *);
static void cp_parser_skip_to_end_of_block_or_statement
  (cp_parser *);
static bool cp_parser_skip_to_closing_brace
  (cp_parser *);
static void cp_parser_skip_to_end_of_template_parameter_list
  (cp_parser *);
static void cp_parser_skip_to_pragma_eol
  (cp_parser*, cp_token *);
static bool cp_parser_error_occurred
  (cp_parser *);
static bool cp_parser_allow_gnu_extensions_p
  (cp_parser *);
static bool cp_parser_is_pure_string_literal
  (cp_token *);
static bool cp_parser_is_string_literal
  (cp_token *);
static bool cp_parser_is_keyword
  (cp_token *, enum rid);
static tree cp_parser_make_typename_type
  (cp_parser *, tree, location_t location);
static cp_declarator * cp_parser_make_indirect_declarator
  (enum tree_code, tree, cp_cv_quals, cp_declarator *, tree);
static bool cp_parser_compound_literal_p
  (cp_parser *);
static bool cp_parser_array_designator_p
  (cp_parser *);
static bool cp_parser_init_statement_p
  (cp_parser *);
static bool cp_parser_skip_to_closing_square_bracket
  (cp_parser *);

/* Concept-related syntactic transformations */

static tree cp_parser_maybe_concept_name       (cp_parser *, tree);
static tree cp_parser_maybe_partial_concept_id (cp_parser *, tree, tree);

// -------------------------------------------------------------------------- //
// Unevaluated Operand Guard
//
// Implementation of an RAII helper for unevaluated operand parsing.
cp_unevaluated::cp_unevaluated ()
{
  ++cp_unevaluated_operand;
  ++c_inhibit_evaluation_warnings;
}

cp_unevaluated::~cp_unevaluated ()
{
  --c_inhibit_evaluation_warnings;
  --cp_unevaluated_operand;
}

// -------------------------------------------------------------------------- //
// Tentative Parsing

/* Returns nonzero if we are parsing tentatively.  */

static inline bool
cp_parser_parsing_tentatively (cp_parser* parser)
{
  return parser->context->next != NULL;
}

/* Returns nonzero if TOKEN is a string literal.  */

static bool
cp_parser_is_pure_string_literal (cp_token* token)
{
  return (token->type == CPP_STRING ||
	  token->type == CPP_STRING16 ||
	  token->type == CPP_STRING32 ||
	  token->type == CPP_WSTRING ||
	  token->type == CPP_UTF8STRING);
}

/* Returns nonzero if TOKEN is a string literal
   of a user-defined string literal.  */

static bool
cp_parser_is_string_literal (cp_token* token)
{
  return (cp_parser_is_pure_string_literal (token) ||
	  token->type == CPP_STRING_USERDEF ||
	  token->type == CPP_STRING16_USERDEF ||
	  token->type == CPP_STRING32_USERDEF ||
	  token->type == CPP_WSTRING_USERDEF ||
	  token->type == CPP_UTF8STRING_USERDEF);
}

/* Returns nonzero if TOKEN is the indicated KEYWORD.  */

static bool
cp_parser_is_keyword (cp_token* token, enum rid keyword)
{
  return token->keyword == keyword;
}

/* Return TOKEN's pragma_kind if it is CPP_PRAGMA, otherwise
   PRAGMA_NONE.  */

static enum pragma_kind
cp_parser_pragma_kind (cp_token *token)
{
  if (token->type != CPP_PRAGMA)
    return PRAGMA_NONE;
  /* We smuggled the cpp_token->u.pragma value in an INTEGER_CST.  */
  return (enum pragma_kind) TREE_INT_CST_LOW (token->u.value);
}

/* Helper function for cp_parser_error.
   Having peeked a token of kind TOK1_KIND that might signify
   a conflict marker, peek successor tokens to determine
   if we actually do have a conflict marker.
   Specifically, we consider a run of 7 '<', '=' or '>' characters
   at the start of a line as a conflict marker.
   These come through the lexer as three pairs and a single,
   e.g. three CPP_LSHIFT tokens ("<<") and a CPP_LESS token ('<').
   If it returns true, *OUT_LOC is written to with the location/range
   of the marker.  */

static bool
cp_lexer_peek_conflict_marker (cp_lexer *lexer, enum cpp_ttype tok1_kind,
			       location_t *out_loc)
{
  cp_token *token2 = cp_lexer_peek_nth_token (lexer, 2);
  if (token2->type != tok1_kind)
    return false;
  cp_token *token3 = cp_lexer_peek_nth_token (lexer, 3);
  if (token3->type != tok1_kind)
    return false;
  cp_token *token4 = cp_lexer_peek_nth_token (lexer, 4);
  if (token4->type != conflict_marker_get_final_tok_kind (tok1_kind))
    return false;

  /* It must be at the start of the line.  */
  location_t start_loc = cp_lexer_peek_token (lexer)->location;
  if (LOCATION_COLUMN (start_loc) != 1)
    return false;

  /* We have a conflict marker.  Construct a location of the form:
       <<<<<<<
       ^~~~~~~
     with start == caret, finishing at the end of the marker.  */
  location_t finish_loc = get_finish (token4->location);
  *out_loc = make_location (start_loc, start_loc, finish_loc);

  return true;
}

/* Get a description of the matching symbol to TOKEN_DESC e.g. "(" for
   RT_CLOSE_PAREN.  */

static const char *
get_matching_symbol (required_token token_desc)
{
  switch (token_desc)
    {
    default:
      gcc_unreachable ();
      return "";
    case RT_CLOSE_BRACE:
      return "{";
    case RT_CLOSE_PAREN:
      return "(";
    }
}

/* Attempt to convert TOKEN_DESC from a required_token to an
   enum cpp_ttype, returning CPP_EOF if there is no good conversion.  */

static enum cpp_ttype
get_required_cpp_ttype (required_token token_desc)
{
  switch (token_desc)
    {
    case RT_SEMICOLON:
      return CPP_SEMICOLON;
    case RT_OPEN_PAREN:
      return CPP_OPEN_PAREN;
    case RT_CLOSE_BRACE:
      return CPP_CLOSE_BRACE;
    case RT_OPEN_BRACE:
      return CPP_OPEN_BRACE;
    case RT_CLOSE_SQUARE:
      return CPP_CLOSE_SQUARE;
    case RT_OPEN_SQUARE:
      return CPP_OPEN_SQUARE;
    case RT_COMMA:
      return CPP_COMMA;
    case RT_COLON:
      return CPP_COLON;
    case RT_CLOSE_PAREN:
      return CPP_CLOSE_PAREN;

    default:
      /* Use CPP_EOF as a "no completions possible" code.  */
      return CPP_EOF;
    }
}


/* Subroutine of cp_parser_error and cp_parser_required_error.

   Issue a diagnostic of the form
      FILE:LINE: MESSAGE before TOKEN
   where TOKEN is the next token in the input stream.  MESSAGE
   (specified by the caller) is usually of the form "expected
   OTHER-TOKEN".

   This bypasses the check for tentative passing, and potentially
   adds material needed by cp_parser_required_error.

   If MISSING_TOKEN_DESC is not RT_NONE, then potentially add fix-it hints
   suggesting insertion of the missing token.

   Additionally, if MATCHING_LOCATION is not UNKNOWN_LOCATION, then we
   have an unmatched symbol at MATCHING_LOCATION; highlight this secondary
   location.  */

static void
cp_parser_error_1 (cp_parser* parser, const char* gmsgid,
		   required_token missing_token_desc,
		   location_t matching_location)
{
  cp_token *token = cp_lexer_peek_token (parser->lexer);
  /* This diagnostic makes more sense if it is tagged to the line
     of the token we just peeked at.  */
  cp_lexer_set_source_position_from_token (token);

  if (token->type == CPP_PRAGMA)
    {
      error_at (token->location,
		"%<#pragma%> is not allowed here");
      cp_parser_skip_to_pragma_eol (parser, token);
      return;
    }

  /* If this is actually a conflict marker, report it as such.  */
  if (token->type == CPP_LSHIFT
      || token->type == CPP_RSHIFT
      || token->type == CPP_EQ_EQ)
    {
      location_t loc;
      if (cp_lexer_peek_conflict_marker (parser->lexer, token->type, &loc))
	{
	  error_at (loc, "version control conflict marker in file");
	  return;
	}
    }

  gcc_rich_location richloc (input_location);

  bool added_matching_location = false;

  if (missing_token_desc != RT_NONE)
    {
      /* Potentially supply a fix-it hint, suggesting to add the
	 missing token immediately after the *previous* token.
	 This may move the primary location within richloc.  */
      enum cpp_ttype ttype = get_required_cpp_ttype (missing_token_desc);
      location_t prev_token_loc
	= cp_lexer_previous_token (parser->lexer)->location;
      maybe_suggest_missing_token_insertion (&richloc, ttype, prev_token_loc);

      /* If matching_location != UNKNOWN_LOCATION, highlight it.
	 Attempt to consolidate diagnostics by printing it as a
	secondary range within the main diagnostic.  */
      if (matching_location != UNKNOWN_LOCATION)
	added_matching_location
	  = richloc.add_location_if_nearby (matching_location);
    }

  /* Actually emit the error.  */
  c_parse_error (gmsgid,
		 /* Because c_parser_error does not understand
		    CPP_KEYWORD, keywords are treated like
		    identifiers.  */
		 (token->type == CPP_KEYWORD ? CPP_NAME : token->type),
		 token->u.value, token->flags, &richloc);

  if (missing_token_desc != RT_NONE)
    {
      /* If we weren't able to consolidate matching_location, then
	 print it as a secondary diagnostic.  */
      if (matching_location != UNKNOWN_LOCATION
	  && !added_matching_location)
	inform (matching_location, "to match this %qs",
		get_matching_symbol (missing_token_desc));
    }
}

/* If not parsing tentatively, issue a diagnostic of the form
      FILE:LINE: MESSAGE before TOKEN
   where TOKEN is the next token in the input stream.  MESSAGE
   (specified by the caller) is usually of the form "expected
   OTHER-TOKEN".  */

static void
cp_parser_error (cp_parser* parser, const char* gmsgid)
{
  if (!cp_parser_simulate_error (parser))
    cp_parser_error_1 (parser, gmsgid, RT_NONE, UNKNOWN_LOCATION);
}

/* Issue an error about name-lookup failing.  NAME is the
   IDENTIFIER_NODE DECL is the result of
   the lookup (as returned from cp_parser_lookup_name).  DESIRED is
   the thing that we hoped to find.  */

static void
cp_parser_name_lookup_error (cp_parser* parser,
			     tree name,
			     tree decl,
			     name_lookup_error desired,
			     location_t location)
{
  /* If name lookup completely failed, tell the user that NAME was not
     declared.  */
  if (decl == error_mark_node)
    {
      if (parser->scope && parser->scope != global_namespace)
	error_at (location, "%<%E::%E%> has not been declared",
		  parser->scope, name);
      else if (parser->scope == global_namespace)
	error_at (location, "%<::%E%> has not been declared", name);
      else if (parser->object_scope
	       && !CLASS_TYPE_P (parser->object_scope))
	error_at (location, "request for member %qE in non-class type %qT",
		  name, parser->object_scope);
      else if (parser->object_scope)
	error_at (location, "%<%T::%E%> has not been declared",
		  parser->object_scope, name);
      else
	error_at (location, "%qE has not been declared", name);
    }
  else if (parser->scope && parser->scope != global_namespace)
    {
      switch (desired)
	{
	  case NLE_TYPE:
	    error_at (location, "%<%E::%E%> is not a type",
	    			parser->scope, name);
	    break;
	  case NLE_CXX98:
	    error_at (location, "%<%E::%E%> is not a class or namespace",
	    			parser->scope, name);
	    break;
	  case NLE_NOT_CXX98:
	    error_at (location,
	    	      "%<%E::%E%> is not a class, namespace, or enumeration",
		      parser->scope, name);
	    break;
	  default:
	    gcc_unreachable ();
	    
	}
    }
  else if (parser->scope == global_namespace)
    {
      switch (desired)
	{
	  case NLE_TYPE:
	    error_at (location, "%<::%E%> is not a type", name);
	    break;
	  case NLE_CXX98:
	    error_at (location, "%<::%E%> is not a class or namespace", name);
	    break;
	  case NLE_NOT_CXX98:
	    error_at (location,
		      "%<::%E%> is not a class, namespace, or enumeration",
		      name);
	    break;
	  default:
	    gcc_unreachable ();
	}
    }
  else
    {
      switch (desired)
	{
	  case NLE_TYPE:
	    error_at (location, "%qE is not a type", name);
	    break;
	  case NLE_CXX98:
	    error_at (location, "%qE is not a class or namespace", name);
	    break;
	  case NLE_NOT_CXX98:
	    error_at (location,
		      "%qE is not a class, namespace, or enumeration", name);
	    break;
	  default:
	    gcc_unreachable ();
	}
    }
}

/* If we are parsing tentatively, remember that an error has occurred
   during this tentative parse.  Returns true if the error was
   simulated; false if a message should be issued by the caller.  */

static bool
cp_parser_simulate_error (cp_parser* parser)
{
  if (cp_parser_uncommitted_to_tentative_parse_p (parser))
    {
      parser->context->status = CP_PARSER_STATUS_KIND_ERROR;
      return true;
    }
  return false;
}

/* This function is called when a type is defined.  If type
   definitions are forbidden at this point, an error message is
   issued.  */

static bool
cp_parser_check_type_definition (cp_parser* parser)
{
  /* If types are forbidden here, issue a message.  */
  if (parser->type_definition_forbidden_message)
    {
      /* Don't use `%s' to print the string, because quotations (`%<', `%>')
	 in the message need to be interpreted.  */
      error (parser->type_definition_forbidden_message);
      return false;
    }
  return true;
}

/* This function is called when the DECLARATOR is processed.  The TYPE
   was a type defined in the decl-specifiers.  If it is invalid to
   define a type in the decl-specifiers for DECLARATOR, an error is
   issued. TYPE_LOCATION is the location of TYPE and is used
   for error reporting.  */

static void
cp_parser_check_for_definition_in_return_type (cp_declarator *declarator,
					       tree type, location_t type_location)
{
  /* [dcl.fct] forbids type definitions in return types.
     Unfortunately, it's not easy to know whether or not we are
     processing a return type until after the fact.  */
  while (declarator
	 && (declarator->kind == cdk_pointer
	     || declarator->kind == cdk_reference
	     || declarator->kind == cdk_ptrmem))
    declarator = declarator->declarator;
  if (declarator
      && declarator->kind == cdk_function)
    {
      error_at (type_location,
		"new types may not be defined in a return type");
      inform (type_location, 
	      "(perhaps a semicolon is missing after the definition of %qT)",
	      type);
    }
}

/* A type-specifier (TYPE) has been parsed which cannot be followed by
   "<" in any valid C++ program.  If the next token is indeed "<",
   issue a message warning the user about what appears to be an
   invalid attempt to form a template-id. LOCATION is the location
   of the type-specifier (TYPE) */

static void
cp_parser_check_for_invalid_template_id (cp_parser* parser,
					 tree type,
					 enum tag_types tag_type,
					 location_t location)
{
  cp_token_position start = 0;

  if (cp_lexer_next_token_is (parser->lexer, CPP_LESS))
    {
      if (TREE_CODE (type) == TYPE_DECL)
	type = TREE_TYPE (type);
      if (TYPE_P (type) && !template_placeholder_p (type))
	error_at (location, "%qT is not a template", type);
      else if (identifier_p (type))
	{
	  if (tag_type != none_type)
	    error_at (location, "%qE is not a class template", type);
	  else
	    error_at (location, "%qE is not a template", type);
	}
      else
	error_at (location, "invalid template-id");
      /* Remember the location of the invalid "<".  */
      if (cp_parser_uncommitted_to_tentative_parse_p (parser))
	start = cp_lexer_token_position (parser->lexer, true);
      /* Consume the "<".  */
      cp_lexer_consume_token (parser->lexer);
      /* Parse the template arguments.  */
      cp_parser_enclosed_template_argument_list (parser);
      /* Permanently remove the invalid template arguments so that
	 this error message is not issued again.  */
      if (start)
	cp_lexer_purge_tokens_after (parser->lexer, start);
    }
}

/* If parsing an integral constant-expression, issue an error message
   about the fact that THING appeared and return true.  Otherwise,
   return false.  In either case, set
   PARSER->NON_INTEGRAL_CONSTANT_EXPRESSION_P.  */

static bool
cp_parser_non_integral_constant_expression (cp_parser  *parser,
					    non_integral_constant thing)
{
  parser->non_integral_constant_expression_p = true;
  if (parser->integral_constant_expression_p)
    {
      if (!parser->allow_non_integral_constant_expression_p)
	{
	  const char *msg = NULL;
	  switch (thing)
	    {
  	      case NIC_FLOAT:
		pedwarn (input_location, OPT_Wpedantic,
			 "ISO C++ forbids using a floating-point literal "
			 "in a constant-expression");
		return true;
	      case NIC_CAST:
		error ("a cast to a type other than an integral or "
		       "enumeration type cannot appear in a "
		       "constant-expression");
		return true;
	      case NIC_TYPEID:
		error ("%<typeid%> operator "
		       "cannot appear in a constant-expression");
		return true;
	      case NIC_NCC:
		error ("non-constant compound literals "
		       "cannot appear in a constant-expression");
		return true;
	      case NIC_FUNC_CALL:
		error ("a function call "
		       "cannot appear in a constant-expression");
		return true;
	      case NIC_INC:
		error ("an increment "
		       "cannot appear in a constant-expression");
		return true;
	      case NIC_DEC:
		error ("an decrement "
		       "cannot appear in a constant-expression");
		return true;
	      case NIC_ARRAY_REF:
		error ("an array reference "
		       "cannot appear in a constant-expression");
		return true;
	      case NIC_ADDR_LABEL:
		error ("the address of a label "
		       "cannot appear in a constant-expression");
		return true;
	      case NIC_OVERLOADED:
		error ("calls to overloaded operators "
		       "cannot appear in a constant-expression");
		return true;
	      case NIC_ASSIGNMENT:
		error ("an assignment cannot appear in a constant-expression");
		return true;
	      case NIC_COMMA:
		error ("a comma operator "
		       "cannot appear in a constant-expression");
		return true;
	      case NIC_CONSTRUCTOR:
		error ("a call to a constructor "
		       "cannot appear in a constant-expression");
		return true;
	      case NIC_TRANSACTION:
		error ("a transaction expression "
		       "cannot appear in a constant-expression");
		return true;
	      case NIC_THIS:
		msg = "this";
		break;
	      case NIC_FUNC_NAME:
		msg = "__FUNCTION__";
		break;
  	      case NIC_PRETTY_FUNC:
		msg = "__PRETTY_FUNCTION__";
		break;
	      case NIC_C99_FUNC:
		msg = "__func__";
		break;
	      case NIC_VA_ARG:
		msg = "va_arg";
		break;
	      case NIC_ARROW:
		msg = "->";
		break;
	      case NIC_POINT:
		msg = ".";
		break;
	      case NIC_STAR:
		msg = "*";
		break;
	      case NIC_ADDR:
		msg = "&";
		break;
	      case NIC_PREINCREMENT:
		msg = "++";
		break;
	      case NIC_PREDECREMENT:
		msg = "--";
		break;
	      case NIC_NEW:
		msg = "new";
		break;
	      case NIC_DEL:
		msg = "delete";
		break;
	      default:
		gcc_unreachable ();
	    }
	  if (msg)
	    error ("%qs cannot appear in a constant-expression", msg);
	  return true;
	}
    }
  return false;
}

/* Emit a diagnostic for an invalid type name.  This function commits
   to the current active tentative parse, if any.  (Otherwise, the
   problematic construct might be encountered again later, resulting
   in duplicate error messages.) LOCATION is the location of ID.  */

static void
cp_parser_diagnose_invalid_type_name (cp_parser *parser, tree id,
				      location_t location)
{
  tree decl, ambiguous_decls;
  cp_parser_commit_to_tentative_parse (parser);
  /* Try to lookup the identifier.  */
  decl = cp_parser_lookup_name (parser, id, none_type,
				/*is_template=*/false,
				/*is_namespace=*/false,
				/*check_dependency=*/true,
				&ambiguous_decls, location);
  if (ambiguous_decls)
    /* If the lookup was ambiguous, an error will already have
       been issued.  */
    return;
  /* If the lookup found a template-name, it means that the user forgot
  to specify an argument list. Emit a useful error message.  */
  if (DECL_TYPE_TEMPLATE_P (decl))
    {
      error_at (location,
		"invalid use of template-name %qE without an argument list",
		decl);
      if (DECL_CLASS_TEMPLATE_P (decl) && cxx_dialect < cxx17)
	inform (location, "class template argument deduction is only available "
		"with -std=c++17 or -std=gnu++17");
      inform (DECL_SOURCE_LOCATION (decl), "%qD declared here", decl);
    }
  else if (TREE_CODE (id) == BIT_NOT_EXPR)
    error_at (location, "invalid use of destructor %qD as a type", id);
  else if (TREE_CODE (decl) == TYPE_DECL)
    /* Something like 'unsigned A a;'  */
    error_at (location, "invalid combination of multiple type-specifiers");
  else if (!parser->scope)
    {
      /* Issue an error message.  */
      const char *suggestion = NULL;
      if (TREE_CODE (id) == IDENTIFIER_NODE)
        suggestion = lookup_name_fuzzy (id, FUZZY_LOOKUP_TYPENAME);
      if (suggestion)
	{
	  gcc_rich_location richloc (location);
	  richloc.add_fixit_replace (suggestion);
	  error_at_rich_loc (&richloc,
			     "%qE does not name a type; did you mean %qs?",
			     id, suggestion);
	}
      else
	error_at (location, "%qE does not name a type", id);
      /* If we're in a template class, it's possible that the user was
	 referring to a type from a base class.  For example:

	   template <typename T> struct A { typedef T X; };
	   template <typename T> struct B : public A<T> { X x; };

	 The user should have said "typename A<T>::X".  */
      if (cxx_dialect < cxx11 && id == ridpointers[(int)RID_CONSTEXPR])
	inform (location, "C++11 %<constexpr%> only available with "
		"-std=c++11 or -std=gnu++11");
      else if (cxx_dialect < cxx11 && id == ridpointers[(int)RID_NOEXCEPT])
	inform (location, "C++11 %<noexcept%> only available with "
		"-std=c++11 or -std=gnu++11");
      else if (cxx_dialect < cxx11
	       && TREE_CODE (id) == IDENTIFIER_NODE
	       && id_equal (id, "thread_local"))
	inform (location, "C++11 %<thread_local%> only available with "
		"-std=c++11 or -std=gnu++11");
      else if (!flag_concepts && id == ridpointers[(int)RID_CONCEPT])
	inform (location, "%<concept%> only available with -fconcepts");
      else if (processing_template_decl && current_class_type
	       && TYPE_BINFO (current_class_type))
	{
	  tree b;

	  for (b = TREE_CHAIN (TYPE_BINFO (current_class_type));
	       b;
	       b = TREE_CHAIN (b))
	    {
	      tree base_type = BINFO_TYPE (b);
	      if (CLASS_TYPE_P (base_type)
		  && dependent_type_p (base_type))
		{
		  tree field;
		  /* Go from a particular instantiation of the
		     template (which will have an empty TYPE_FIELDs),
		     to the main version.  */
		  base_type = CLASSTYPE_PRIMARY_TEMPLATE_TYPE (base_type);
		  for (field = TYPE_FIELDS (base_type);
		       field;
		       field = DECL_CHAIN (field))
		    if (TREE_CODE (field) == TYPE_DECL
			&& DECL_NAME (field) == id)
		      {
			inform (location, 
				"(perhaps %<typename %T::%E%> was intended)",
				BINFO_TYPE (b), id);
			break;
		      }
		  if (field)
		    break;
		}
	    }
	}
    }
  /* Here we diagnose qualified-ids where the scope is actually correct,
     but the identifier does not resolve to a valid type name.  */
  else if (parser->scope != error_mark_node)
    {
      if (TREE_CODE (parser->scope) == NAMESPACE_DECL)
	{
	  if (cp_lexer_next_token_is (parser->lexer, CPP_LESS))
	    error_at (location_of (id),
		      "%qE in namespace %qE does not name a template type",
		      id, parser->scope);
	  else if (TREE_CODE (id) == TEMPLATE_ID_EXPR)
	    error_at (location_of (id),
		      "%qE in namespace %qE does not name a template type",
		      TREE_OPERAND (id, 0), parser->scope);
	  else
	    error_at (location_of (id),
		      "%qE in namespace %qE does not name a type",
		      id, parser->scope);
	  if (DECL_P (decl))
	    inform (DECL_SOURCE_LOCATION (decl), "%qD declared here", decl);
	}
      else if (CLASS_TYPE_P (parser->scope)
	       && constructor_name_p (id, parser->scope))
	{
	  /* A<T>::A<T>() */
	  error_at (location, "%<%T::%E%> names the constructor, not"
		    " the type", parser->scope, id);
	  if (cp_lexer_next_token_is (parser->lexer, CPP_LESS))
	    error_at (location, "and %qT has no template constructors",
		      parser->scope);
	}
      else if (TYPE_P (parser->scope)
	       && dependent_scope_p (parser->scope))
	{
	  if (TREE_CODE (parser->scope) == TYPENAME_TYPE)
	    error_at (location,
		      "need %<typename%> before %<%T::%D::%E%> because "
		      "%<%T::%D%> is a dependent scope",
		      TYPE_CONTEXT (parser->scope),
		      TYPENAME_TYPE_FULLNAME (parser->scope),
		      id,
		      TYPE_CONTEXT (parser->scope),
		      TYPENAME_TYPE_FULLNAME (parser->scope));
	  else
	    error_at (location, "need %<typename%> before %<%T::%E%> because "
		      "%qT is a dependent scope",
		      parser->scope, id, parser->scope);
	}
      else if (TYPE_P (parser->scope))
	{
	  if (!COMPLETE_TYPE_P (parser->scope))
	    cxx_incomplete_type_error (location_of (id), NULL_TREE,
				       parser->scope);
	  else if (cp_lexer_next_token_is (parser->lexer, CPP_LESS))
	    error_at (location_of (id),
		      "%qE in %q#T does not name a template type",
		      id, parser->scope);
	  else if (TREE_CODE (id) == TEMPLATE_ID_EXPR)
	    error_at (location_of (id),
		      "%qE in %q#T does not name a template type",
		      TREE_OPERAND (id, 0), parser->scope);
	  else
	    error_at (location_of (id),
		      "%qE in %q#T does not name a type",
		      id, parser->scope);
	  if (DECL_P (decl))
	    inform (DECL_SOURCE_LOCATION (decl), "%qD declared here", decl);
	}
      else
	gcc_unreachable ();
    }
}

/* Check for a common situation where a type-name should be present,
   but is not, and issue a sensible error message.  Returns true if an
   invalid type-name was detected.

   The situation handled by this function are variable declarations of the
   form `ID a', where `ID' is an id-expression and `a' is a plain identifier.
   Usually, `ID' should name a type, but if we got here it means that it
   does not. We try to emit the best possible error message depending on
   how exactly the id-expression looks like.  */

static bool
cp_parser_parse_and_diagnose_invalid_type_name (cp_parser *parser)
{
  tree id;
  cp_token *token = cp_lexer_peek_token (parser->lexer);

  /* Avoid duplicate error about ambiguous lookup.  */
  if (token->type == CPP_NESTED_NAME_SPECIFIER)
    {
      cp_token *next = cp_lexer_peek_nth_token (parser->lexer, 2);
      if (next->type == CPP_NAME && next->error_reported)
	goto out;
    }

  cp_parser_parse_tentatively (parser);
  id = cp_parser_id_expression (parser,
				/*template_keyword_p=*/false,
				/*check_dependency_p=*/true,
				/*template_p=*/NULL,
				/*declarator_p=*/true,
				/*optional_p=*/false);
  /* If the next token is a (, this is a function with no explicit return
     type, i.e. constructor, destructor or conversion op.  */
  if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_PAREN)
      || TREE_CODE (id) == TYPE_DECL)
    {
      cp_parser_abort_tentative_parse (parser);
      return false;
    }
  if (!cp_parser_parse_definitely (parser))
    return false;

  /* Emit a diagnostic for the invalid type.  */
  cp_parser_diagnose_invalid_type_name (parser, id, token->location);
 out:
  /* If we aren't in the middle of a declarator (i.e. in a
     parameter-declaration-clause), skip to the end of the declaration;
     there's no point in trying to process it.  */
  if (!parser->in_declarator_p)
    cp_parser_skip_to_end_of_block_or_statement (parser);
  return true;
}

/* Consume tokens up to, and including, the next non-nested closing `)'.
   Returns 1 iff we found a closing `)'.  RECOVERING is true, if we
   are doing error recovery. Returns -1 if OR_TTYPE is not CPP_EOF and we
   found an unnested token of that type.  */

static int
cp_parser_skip_to_closing_parenthesis_1 (cp_parser *parser,
					 bool recovering,
					 cpp_ttype or_ttype,
					 bool consume_paren)
{
  unsigned paren_depth = 0;
  unsigned brace_depth = 0;
  unsigned square_depth = 0;

  if (recovering && or_ttype == CPP_EOF
      && cp_parser_uncommitted_to_tentative_parse_p (parser))
    return 0;

  while (true)
    {
      cp_token * token = cp_lexer_peek_token (parser->lexer);

      /* Have we found what we're looking for before the closing paren?  */
      if (token->type == or_ttype && or_ttype != CPP_EOF
	  && !brace_depth && !paren_depth && !square_depth)
	return -1;

      switch (token->type)
	{
	case CPP_EOF:
	case CPP_PRAGMA_EOL:
	  /* If we've run out of tokens, then there is no closing `)'.  */
	  return 0;

        /* This is good for lambda expression capture-lists.  */
        case CPP_OPEN_SQUARE:
          ++square_depth;
          break;
        case CPP_CLOSE_SQUARE:
          if (!square_depth--)
            return 0;
          break;

	case CPP_SEMICOLON:
	  /* This matches the processing in skip_to_end_of_statement.  */
	  if (!brace_depth)
	    return 0;
	  break;

	case CPP_OPEN_BRACE:
	  ++brace_depth;
	  break;
	case CPP_CLOSE_BRACE:
	  if (!brace_depth--)
	    return 0;
	  break;

	case CPP_OPEN_PAREN:
	  if (!brace_depth)
	    ++paren_depth;
	  break;

	case CPP_CLOSE_PAREN:
	  if (!brace_depth && !paren_depth--)
	    {
	      if (consume_paren)
		cp_lexer_consume_token (parser->lexer);
	      return 1;
	    }
	  break;

	default:
	  break;
	}

      /* Consume the token.  */
      cp_lexer_consume_token (parser->lexer);
    }
}

/* Consume tokens up to, and including, the next non-nested closing `)'.
   Returns 1 iff we found a closing `)'.  RECOVERING is true, if we
   are doing error recovery. Returns -1 if OR_COMMA is true and we
   found an unnested token of that type.  */

static int
cp_parser_skip_to_closing_parenthesis (cp_parser *parser,
				       bool recovering,
				       bool or_comma,
				       bool consume_paren)
{
  cpp_ttype ttype = or_comma ? CPP_COMMA : CPP_EOF;
  return cp_parser_skip_to_closing_parenthesis_1 (parser, recovering,
						  ttype, consume_paren);
}

/* Consume tokens until we reach the end of the current statement.
   Normally, that will be just before consuming a `;'.  However, if a
   non-nested `}' comes first, then we stop before consuming that.  */

static void
cp_parser_skip_to_end_of_statement (cp_parser* parser)
{
  unsigned nesting_depth = 0;

  /* Unwind generic function template scope if necessary.  */
  if (parser->fully_implicit_function_template_p)
    finish_fully_implicit_template (parser, /*member_decl_opt=*/0);

  while (true)
    {
      cp_token *token = cp_lexer_peek_token (parser->lexer);

      switch (token->type)
	{
	case CPP_EOF:
	case CPP_PRAGMA_EOL:
	  /* If we've run out of tokens, stop.  */
	  return;

	case CPP_SEMICOLON:
	  /* If the next token is a `;', we have reached the end of the
	     statement.  */
	  if (!nesting_depth)
	    return;
	  break;

	case CPP_CLOSE_BRACE:
	  /* If this is a non-nested '}', stop before consuming it.
	     That way, when confronted with something like:

	       { 3 + }

	     we stop before consuming the closing '}', even though we
	     have not yet reached a `;'.  */
	  if (nesting_depth == 0)
	    return;

	  /* If it is the closing '}' for a block that we have
	     scanned, stop -- but only after consuming the token.
	     That way given:

		void f g () { ... }
		typedef int I;

	     we will stop after the body of the erroneously declared
	     function, but before consuming the following `typedef'
	     declaration.  */
	  if (--nesting_depth == 0)
	    {
	      cp_lexer_consume_token (parser->lexer);
	      return;
	    }
	  break;

	case CPP_OPEN_BRACE:
	  ++nesting_depth;
	  break;

	default:
	  break;
	}

      /* Consume the token.  */
      cp_lexer_consume_token (parser->lexer);
    }
}

/* This function is called at the end of a statement or declaration.
   If the next token is a semicolon, it is consumed; otherwise, error
   recovery is attempted.  */

static void
cp_parser_consume_semicolon_at_end_of_statement (cp_parser *parser)
{
  /* Look for the trailing `;'.  */
  if (!cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON))
    {
      /* If there is additional (erroneous) input, skip to the end of
	 the statement.  */
      cp_parser_skip_to_end_of_statement (parser);
      /* If the next token is now a `;', consume it.  */
      if (cp_lexer_next_token_is (parser->lexer, CPP_SEMICOLON))
	cp_lexer_consume_token (parser->lexer);
    }
}

/* Skip tokens until we have consumed an entire block, or until we
   have consumed a non-nested `;'.  */

static void
cp_parser_skip_to_end_of_block_or_statement (cp_parser* parser)
{
  int nesting_depth = 0;

  /* Unwind generic function template scope if necessary.  */
  if (parser->fully_implicit_function_template_p)
    finish_fully_implicit_template (parser, /*member_decl_opt=*/0);

  while (nesting_depth >= 0)
    {
      cp_token *token = cp_lexer_peek_token (parser->lexer);

      switch (token->type)
	{
	case CPP_EOF:
	case CPP_PRAGMA_EOL:
	  /* If we've run out of tokens, stop.  */
	  return;

	case CPP_SEMICOLON:
	  /* Stop if this is an unnested ';'. */
	  if (!nesting_depth)
	    nesting_depth = -1;
	  break;

	case CPP_CLOSE_BRACE:
	  /* Stop if this is an unnested '}', or closes the outermost
	     nesting level.  */
	  nesting_depth--;
	  if (nesting_depth < 0)
	    return;
	  if (!nesting_depth)
	    nesting_depth = -1;
	  break;

	case CPP_OPEN_BRACE:
	  /* Nest. */
	  nesting_depth++;
	  break;

	default:
	  break;
	}

      /* Consume the token.  */
      cp_lexer_consume_token (parser->lexer);
    }
}

/* Skip tokens until a non-nested closing curly brace is the next
   token, or there are no more tokens. Return true in the first case,
   false otherwise.  */

static bool
cp_parser_skip_to_closing_brace (cp_parser *parser)
{
  unsigned nesting_depth = 0;

  while (true)
    {
      cp_token *token = cp_lexer_peek_token (parser->lexer);

      switch (token->type)
	{
	case CPP_EOF:
	case CPP_PRAGMA_EOL:
	  /* If we've run out of tokens, stop.  */
	  return false;

	case CPP_CLOSE_BRACE:
	  /* If the next token is a non-nested `}', then we have reached
	     the end of the current block.  */
	  if (nesting_depth-- == 0)
	    return true;
	  break;

	case CPP_OPEN_BRACE:
	  /* If it the next token is a `{', then we are entering a new
	     block.  Consume the entire block.  */
	  ++nesting_depth;
	  break;

	default:
	  break;
	}

      /* Consume the token.  */
      cp_lexer_consume_token (parser->lexer);
    }
}

/* Consume tokens until we reach the end of the pragma.  The PRAGMA_TOK
   parameter is the PRAGMA token, allowing us to purge the entire pragma
   sequence.  */

static void
cp_parser_skip_to_pragma_eol (cp_parser* parser, cp_token *pragma_tok)
{
  cp_token *token;

  parser->lexer->in_pragma = false;

  do
    token = cp_lexer_consume_token (parser->lexer);
  while (token->type != CPP_PRAGMA_EOL && token->type != CPP_EOF);

  /* Ensure that the pragma is not parsed again.  */
  cp_lexer_purge_tokens_after (parser->lexer, pragma_tok);
}

/* Require pragma end of line, resyncing with it as necessary.  The
   arguments are as for cp_parser_skip_to_pragma_eol.  */

static void
cp_parser_require_pragma_eol (cp_parser *parser, cp_token *pragma_tok)
{
  parser->lexer->in_pragma = false;
  if (!cp_parser_require (parser, CPP_PRAGMA_EOL, RT_PRAGMA_EOL))
    cp_parser_skip_to_pragma_eol (parser, pragma_tok);
}

/* This is a simple wrapper around make_typename_type. When the id is
   an unresolved identifier node, we can provide a superior diagnostic
   using cp_parser_diagnose_invalid_type_name.  */

static tree
cp_parser_make_typename_type (cp_parser *parser, tree id,
			      location_t id_location)
{
  tree result;
  if (identifier_p (id))
    {
      result = make_typename_type (parser->scope, id, typename_type,
				   /*complain=*/tf_none);
      if (result == error_mark_node)
	cp_parser_diagnose_invalid_type_name (parser, id, id_location);
      return result;
    }
  return make_typename_type (parser->scope, id, typename_type, tf_error);
}

/* This is a wrapper around the
   make_{pointer,ptrmem,reference}_declarator functions that decides
   which one to call based on the CODE and CLASS_TYPE arguments. The
   CODE argument should be one of the values returned by
   cp_parser_ptr_operator.  ATTRIBUTES represent the attributes that
   appertain to the pointer or reference.  */

static cp_declarator *
cp_parser_make_indirect_declarator (enum tree_code code, tree class_type,
				    cp_cv_quals cv_qualifiers,
				    cp_declarator *target,
				    tree attributes)
{
  if (code == ERROR_MARK)
    return cp_error_declarator;

  if (code == INDIRECT_REF)
    if (class_type == NULL_TREE)
      return make_pointer_declarator (cv_qualifiers, target, attributes);
    else
      return make_ptrmem_declarator (cv_qualifiers, class_type,
				     target, attributes);
  else if (code == ADDR_EXPR && class_type == NULL_TREE)
    return make_reference_declarator (cv_qualifiers, target,
				      false, attributes);
  else if (code == NON_LVALUE_EXPR && class_type == NULL_TREE)
    return make_reference_declarator (cv_qualifiers, target,
				      true, attributes);
  gcc_unreachable ();
}

/* Create a new C++ parser.  */

static cp_parser *
cp_parser_new (void)
{
  cp_parser *parser;
  cp_lexer *lexer;
  unsigned i;

  /* cp_lexer_new_main is called before doing GC allocation because
     cp_lexer_new_main might load a PCH file.  */
  lexer = cp_lexer_new_main ();

  /* Initialize the binops_by_token so that we can get the tree
     directly from the token.  */
  for (i = 0; i < sizeof (binops) / sizeof (binops[0]); i++)
    binops_by_token[binops[i].token_type] = binops[i];

  parser = ggc_cleared_alloc<cp_parser> ();
  parser->lexer = lexer;
  parser->context = cp_parser_context_new (NULL);

  /* For now, we always accept GNU extensions.  */
  parser->allow_gnu_extensions_p = 1;

  /* The `>' token is a greater-than operator, not the end of a
     template-id.  */
  parser->greater_than_is_operator_p = true;

  parser->default_arg_ok_p = true;

  /* We are not parsing a constant-expression.  */
  parser->integral_constant_expression_p = false;
  parser->allow_non_integral_constant_expression_p = false;
  parser->non_integral_constant_expression_p = false;

  /* Local variable names are not forbidden.  */
  parser->local_variables_forbidden_p = false;

  /* We are not processing an `extern "C"' declaration.  */
  parser->in_unbraced_linkage_specification_p = false;

  /* We are not processing a declarator.  */
  parser->in_declarator_p = false;

  /* We are not processing a template-argument-list.  */
  parser->in_template_argument_list_p = false;

  /* We are not in an iteration statement.  */
  parser->in_statement = 0;

  /* We are not in a switch statement.  */
  parser->in_switch_statement_p = false;

  /* We are not parsing a type-id inside an expression.  */
  parser->in_type_id_in_expr_p = false;

  /* Declarations aren't implicitly extern "C".  */
  parser->implicit_extern_c = false;

  /* String literals should be translated to the execution character set.  */
  parser->translate_strings_p = true;

  /* We are not parsing a function body.  */
  parser->in_function_body = false;

  /* We can correct until told otherwise.  */
  parser->colon_corrects_to_scope_p = true;

  /* The unparsed function queue is empty.  */
  push_unparsed_function_queues (parser);

  /* There are no classes being defined.  */
  parser->num_classes_being_defined = 0;

  /* No template parameters apply.  */
  parser->num_template_parameter_lists = 0;

  /* Special parsing data structures.  */
  parser->omp_declare_simd = NULL;
  parser->cilk_simd_fn_info = NULL;
  parser->oacc_routine = NULL;

  /* Not declaring an implicit function template.  */
  parser->auto_is_implicit_function_template_parm_p = false;
  parser->fully_implicit_function_template_p = false;
  parser->implicit_template_parms = 0;
  parser->implicit_template_scope = 0;

  /* Allow constrained-type-specifiers. */
  parser->prevent_constrained_type_specifiers = 0;

  /* We haven't yet seen an 'extern "C"'.  */
  parser->innermost_linkage_specification_location = UNKNOWN_LOCATION;

  return parser;
}

/* Create a cp_lexer structure which will emit the tokens in CACHE
   and push it onto the parser's lexer stack.  This is used for delayed
   parsing of in-class method bodies and default arguments, and should
   not be confused with tentative parsing.  */
static void
cp_parser_push_lexer_for_tokens (cp_parser *parser, cp_token_cache *cache)
{
  cp_lexer *lexer = cp_lexer_new_from_tokens (cache);
  lexer->next = parser->lexer;
  parser->lexer = lexer;

  /* Move the current source position to that of the first token in the
     new lexer.  */
  cp_lexer_set_source_position_from_token (lexer->next_token);
}

/* Pop the top lexer off the parser stack.  This is never used for the
   "main" lexer, only for those pushed by cp_parser_push_lexer_for_tokens.  */
static void
cp_parser_pop_lexer (cp_parser *parser)
{
  cp_lexer *lexer = parser->lexer;
  parser->lexer = lexer->next;
  cp_lexer_destroy (lexer);

  /* Put the current source position back where it was before this
     lexer was pushed.  */
  cp_lexer_set_source_position_from_token (parser->lexer->next_token);
}

/* Lexical conventions [gram.lex]  */

/* Parse an identifier.  Returns an IDENTIFIER_NODE representing the
   identifier.  */

static cp_expr
cp_parser_identifier (cp_parser* parser)
{
  cp_token *token;

  /* Look for the identifier.  */
  token = cp_parser_require (parser, CPP_NAME, RT_NAME);
  /* Return the value.  */
  if (token)
    return cp_expr (token->u.value, token->location);
  else
    return error_mark_node;
}

/* Parse a sequence of adjacent string constants.  Returns a
   TREE_STRING representing the combined, nul-terminated string
   constant.  If TRANSLATE is true, translate the string to the
   execution character set.  If WIDE_OK is true, a wide string is
   invalid here.

   C++98 [lex.string] says that if a narrow string literal token is
   adjacent to a wide string literal token, the behavior is undefined.
   However, C99 6.4.5p4 says that this results in a wide string literal.
   We follow C99 here, for consistency with the C front end.

   This code is largely lifted from lex_string() in c-lex.c.

   FUTURE: ObjC++ will need to handle @-strings here.  */
static cp_expr
cp_parser_string_literal (cp_parser *parser, bool translate, bool wide_ok,
			  bool lookup_udlit = true)
{
  tree value;
  size_t count;
  struct obstack str_ob;
  cpp_string str, istr, *strs;
  cp_token *tok;
  enum cpp_ttype type, curr_type;
  int have_suffix_p = 0;
  tree string_tree;
  tree suffix_id = NULL_TREE;
  bool curr_tok_is_userdef_p = false;

  tok = cp_lexer_peek_token (parser->lexer);
  if (!cp_parser_is_string_literal (tok))
    {
      cp_parser_error (parser, "expected string-literal");
      return error_mark_node;
    }

  location_t loc = tok->location;

  if (cpp_userdef_string_p (tok->type))
    {
      string_tree = USERDEF_LITERAL_VALUE (tok->u.value);
      curr_type = cpp_userdef_string_remove_type (tok->type);
      curr_tok_is_userdef_p = true;
    }
  else
    {
      string_tree = tok->u.value;
      curr_type = tok->type;
    }
  type = curr_type;

  /* Try to avoid the overhead of creating and destroying an obstack
     for the common case of just one string.  */
  if (!cp_parser_is_string_literal
      (cp_lexer_peek_nth_token (parser->lexer, 2)))
    {
      cp_lexer_consume_token (parser->lexer);

      str.text = (const unsigned char *)TREE_STRING_POINTER (string_tree);
      str.len = TREE_STRING_LENGTH (string_tree);
      count = 1;

      if (curr_tok_is_userdef_p)
	{
	  suffix_id = USERDEF_LITERAL_SUFFIX_ID (tok->u.value);
	  have_suffix_p = 1;
	  curr_type = cpp_userdef_string_remove_type (tok->type);
	}
      else
	curr_type = tok->type;

      strs = &str;
    }
  else
    {
      location_t last_tok_loc = tok->location;
      gcc_obstack_init (&str_ob);
      count = 0;

      do
	{
	  cp_lexer_consume_token (parser->lexer);
	  count++;
	  str.text = (const unsigned char *)TREE_STRING_POINTER (string_tree);
	  str.len = TREE_STRING_LENGTH (string_tree);

	  if (curr_tok_is_userdef_p)
	    {
	      tree curr_suffix_id = USERDEF_LITERAL_SUFFIX_ID (tok->u.value);
	      if (have_suffix_p == 0)
		{
		  suffix_id = curr_suffix_id;
		  have_suffix_p = 1;
		}
	      else if (have_suffix_p == 1
		       && curr_suffix_id != suffix_id)
		{
		  error ("inconsistent user-defined literal suffixes"
			 " %qD and %qD in string literal",
			 suffix_id, curr_suffix_id);
		  have_suffix_p = -1;
		}
	      curr_type = cpp_userdef_string_remove_type (tok->type);
	    }
	  else
	    curr_type = tok->type;

	  if (type != curr_type)
	    {
	      if (type == CPP_STRING)
		type = curr_type;
	      else if (curr_type != CPP_STRING)
		{
		  rich_location rich_loc (line_table, tok->location);
		  rich_loc.add_range (last_tok_loc, false);
		  error_at_rich_loc (&rich_loc,
				     "unsupported non-standard concatenation "
				     "of string literals");
		}
	    }

	  obstack_grow (&str_ob, &str, sizeof (cpp_string));

	  last_tok_loc = tok->location;

	  tok = cp_lexer_peek_token (parser->lexer);
	  if (cpp_userdef_string_p (tok->type))
	    {
	      string_tree = USERDEF_LITERAL_VALUE (tok->u.value);
	      curr_type = cpp_userdef_string_remove_type (tok->type);
	      curr_tok_is_userdef_p = true;
	    }
	  else
	    {
	      string_tree = tok->u.value;
	      curr_type = tok->type;
	      curr_tok_is_userdef_p = false;
	    }
	}
      while (cp_parser_is_string_literal (tok));

      /* A string literal built by concatenation has its caret=start at
	 the start of the initial string, and its finish at the finish of
	 the final string literal.  */
      loc = make_location (loc, loc, get_finish (last_tok_loc));

      strs = (cpp_string *) obstack_finish (&str_ob);
    }

  if (type != CPP_STRING && !wide_ok)
    {
      cp_parser_error (parser, "a wide string is invalid in this context");
      type = CPP_STRING;
    }

  if ((translate ? cpp_interpret_string : cpp_interpret_string_notranslate)
      (parse_in, strs, count, &istr, type))
    {
      value = build_string (istr.len, (const char *)istr.text);
      free (CONST_CAST (unsigned char *, istr.text));

      switch (type)
	{
	default:
	case CPP_STRING:
	case CPP_UTF8STRING:
	  TREE_TYPE (value) = char_array_type_node;
	  break;
	case CPP_STRING16:
	  TREE_TYPE (value) = char16_array_type_node;
	  break;
	case CPP_STRING32:
	  TREE_TYPE (value) = char32_array_type_node;
	  break;
	case CPP_WSTRING:
	  TREE_TYPE (value) = wchar_array_type_node;
	  break;
	}

      value = fix_string_type (value);

      if (have_suffix_p)
	{
	  tree literal = build_userdef_literal (suffix_id, value,
						OT_NONE, NULL_TREE);
	  if (lookup_udlit)
	    value = cp_parser_userdef_string_literal (literal);
	  else
	    value = literal;
	}
    }
  else
    /* cpp_interpret_string has issued an error.  */
    value = error_mark_node;

  if (count > 1)
    obstack_free (&str_ob, 0);

  return cp_expr (value, loc);
}

/* Look up a literal operator with the name and the exact arguments.  */

static tree
lookup_literal_operator (tree name, vec<tree, va_gc> *args)
{
  tree decl;
  decl = lookup_name (name);
  if (!decl || !is_overloaded_fn (decl))
    return error_mark_node;

  for (lkp_iterator iter (decl); iter; ++iter)
    {
      unsigned int ix;
      bool found = true;
      tree fn = *iter;
      tree parmtypes = TYPE_ARG_TYPES (TREE_TYPE (fn));
      if (parmtypes != NULL_TREE)
	{
	  for (ix = 0; ix < vec_safe_length (args) && parmtypes != NULL_TREE;
	       ++ix, parmtypes = TREE_CHAIN (parmtypes))
	    {
	      tree tparm = TREE_VALUE (parmtypes);
	      tree targ = TREE_TYPE ((*args)[ix]);
	      bool ptr = TYPE_PTR_P (tparm);
	      bool arr = TREE_CODE (targ) == ARRAY_TYPE;
	      if ((ptr || arr || !same_type_p (tparm, targ))
		  && (!ptr || !arr
		      || !same_type_p (TREE_TYPE (tparm),
				       TREE_TYPE (targ))))
		found = false;
	    }
	  if (found
	      && ix == vec_safe_length (args)
	      /* May be this should be sufficient_parms_p instead,
		 depending on how exactly should user-defined literals
		 work in presence of default arguments on the literal
		 operator parameters.  */
	      && parmtypes == void_list_node)
	    return decl;
	}
    }

  return error_mark_node;
}

/* Parse a user-defined char constant.  Returns a call to a user-defined
   literal operator taking the character as an argument.  */

static cp_expr
cp_parser_userdef_char_literal (cp_parser *parser)
{
  cp_token *token = cp_lexer_consume_token (parser->lexer);
  tree literal = token->u.value;
  tree suffix_id = USERDEF_LITERAL_SUFFIX_ID (literal);
  tree value = USERDEF_LITERAL_VALUE (literal);
  tree name = cp_literal_operator_id (IDENTIFIER_POINTER (suffix_id));
  tree decl, result;

  /* Build up a call to the user-defined operator  */
  /* Lookup the name we got back from the id-expression.  */
  vec<tree, va_gc> *args = make_tree_vector ();
  vec_safe_push (args, value);
  decl = lookup_literal_operator (name, args);
  if (!decl || decl == error_mark_node)
    {
      error ("unable to find character literal operator %qD with %qT argument",
	     name, TREE_TYPE (value));
      release_tree_vector (args);
      return error_mark_node;
    }
  result = finish_call_expr (decl, &args, false, true, tf_warning_or_error);
  release_tree_vector (args);
  return result;
}

/* A subroutine of cp_parser_userdef_numeric_literal to
   create a char... template parameter pack from a string node.  */

static tree
make_char_string_pack (tree value)
{
  tree charvec;
  tree argpack = make_node (NONTYPE_ARGUMENT_PACK);
  const char *str = TREE_STRING_POINTER (value);
  int i, len = TREE_STRING_LENGTH (value) - 1;
  tree argvec = make_tree_vec (1);

  /* Fill in CHARVEC with all of the parameters.  */
  charvec = make_tree_vec (len);
  for (i = 0; i < len; ++i)
    TREE_VEC_ELT (charvec, i) = build_int_cst (char_type_node, str[i]);

  /* Build the argument packs.  */
  SET_ARGUMENT_PACK_ARGS (argpack, charvec);

  TREE_VEC_ELT (argvec, 0) = argpack;

  return argvec;
}

/* A subroutine of cp_parser_userdef_numeric_literal to
   create a char... template parameter pack from a string node.  */

static tree
make_string_pack (tree value)
{
  tree charvec;
  tree argpack = make_node (NONTYPE_ARGUMENT_PACK);
  const unsigned char *str
    = (const unsigned char *) TREE_STRING_POINTER (value);
  int sz = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (value))));
  int len = TREE_STRING_LENGTH (value) / sz - 1;
  tree argvec = make_tree_vec (2);

  tree str_char_type_node = TREE_TYPE (TREE_TYPE (value));
  str_char_type_node = TYPE_MAIN_VARIANT (str_char_type_node);

  /* First template parm is character type.  */
  TREE_VEC_ELT (argvec, 0) = str_char_type_node;

  /* Fill in CHARVEC with all of the parameters.  */
  charvec = make_tree_vec (len);
  for (int i = 0; i < len; ++i)
    TREE_VEC_ELT (charvec, i)
      = double_int_to_tree (str_char_type_node,
			    double_int::from_buffer (str + i * sz, sz));

  /* Build the argument packs.  */
  SET_ARGUMENT_PACK_ARGS (argpack, charvec);

  TREE_VEC_ELT (argvec, 1) = argpack;

  return argvec;
}

/* Parse a user-defined numeric constant.  returns a call to a user-defined
   literal operator.  */

static cp_expr
cp_parser_userdef_numeric_literal (cp_parser *parser)
{
  cp_token *token = cp_lexer_consume_token (parser->lexer);
  tree literal = token->u.value;
  tree suffix_id = USERDEF_LITERAL_SUFFIX_ID (literal);
  tree value = USERDEF_LITERAL_VALUE (literal);
  int overflow = USERDEF_LITERAL_OVERFLOW (literal);
  tree num_string = USERDEF_LITERAL_NUM_STRING (literal);
  tree name = cp_literal_operator_id (IDENTIFIER_POINTER (suffix_id));
  tree decl, result;
  vec<tree, va_gc> *args;

  /* Look for a literal operator taking the exact type of numeric argument
     as the literal value.  */
  args = make_tree_vector ();
  vec_safe_push (args, value);
  decl = lookup_literal_operator (name, args);
  if (decl && decl != error_mark_node)
    {
      result = finish_call_expr (decl, &args, false, true,
				 tf_warning_or_error);

      if (TREE_CODE (TREE_TYPE (value)) == INTEGER_TYPE && overflow > 0)
	{
	  warning_at (token->location, OPT_Woverflow,
		      "integer literal exceeds range of %qT type",
		      long_long_unsigned_type_node);
	}
      else
	{
	  if (overflow > 0)
	    warning_at (token->location, OPT_Woverflow,
			"floating literal exceeds range of %qT type",
			long_double_type_node);
	  else if (overflow < 0)
	    warning_at (token->location, OPT_Woverflow,
			"floating literal truncated to zero");
	}

      release_tree_vector (args);
      return result;
    }
  release_tree_vector (args);

  /* If the numeric argument didn't work, look for a raw literal
     operator taking a const char* argument consisting of the number
     in string format.  */
  args = make_tree_vector ();
  vec_safe_push (args, num_string);
  decl = lookup_literal_operator (name, args);
  if (decl && decl != error_mark_node)
    {
      result = finish_call_expr (decl, &args, false, true,
				 tf_warning_or_error);
      release_tree_vector (args);
      return result;
    }
  release_tree_vector (args);

  /* If the raw literal didn't work, look for a non-type template
     function with parameter pack char....  Call the function with
     template parameter characters representing the number.  */
  args = make_tree_vector ();
  decl = lookup_literal_operator (name, args);
  if (decl && decl != error_mark_node)
    {
      tree tmpl_args = make_char_string_pack (num_string);
      decl = lookup_template_function (decl, tmpl_args);
      result = finish_call_expr (decl, &args, false, true,
				 tf_warning_or_error);
      release_tree_vector (args);
      return result;
    }

  release_tree_vector (args);

  error ("unable to find numeric literal operator %qD", name);
  if (!cpp_get_options (parse_in)->ext_numeric_literals)
    inform (token->location, "use -std=gnu++11 or -fext-numeric-literals "
	    "to enable more built-in suffixes");
  return error_mark_node;
}

/* Parse a user-defined string constant.  Returns a call to a user-defined
   literal operator taking a character pointer and the length of the string
   as arguments.  */

static tree
cp_parser_userdef_string_literal (tree literal)
{
  tree suffix_id = USERDEF_LITERAL_SUFFIX_ID (literal);
  tree name = cp_literal_operator_id (IDENTIFIER_POINTER (suffix_id));
  tree value = USERDEF_LITERAL_VALUE (literal);
  int len = TREE_STRING_LENGTH (value)
	/ TREE_INT_CST_LOW (TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (value)))) - 1;
  tree decl, result;
  vec<tree, va_gc> *args;

  /* Build up a call to the user-defined operator.  */
  /* Lookup the name we got back from the id-expression.  */
  args = make_tree_vector ();
  vec_safe_push (args, value);
  vec_safe_push (args, build_int_cst (size_type_node, len));
  decl = lookup_literal_operator (name, args);

  if (decl && decl != error_mark_node)
    {
      result = finish_call_expr (decl, &args, false, true,
				 tf_warning_or_error);
      release_tree_vector (args);
      return result;
    }
  release_tree_vector (args);

  /* Look for a template function with typename parameter CharT
     and parameter pack CharT...  Call the function with
     template parameter characters representing the string.  */
  args = make_tree_vector ();
  decl = lookup_literal_operator (name, args);
  if (decl && decl != error_mark_node)
    {
      tree tmpl_args = make_string_pack (value);
      decl = lookup_template_function (decl, tmpl_args);
      result = finish_call_expr (decl, &args, false, true,
				 tf_warning_or_error);
      release_tree_vector (args);
      return result;
    }
  release_tree_vector (args);

  error ("unable to find string literal operator %qD with %qT, %qT arguments",
	 name, TREE_TYPE (value), size_type_node);
  return error_mark_node;
}


/* Basic concepts [gram.basic]  */

/* Parse a translation-unit.

   translation-unit:
     declaration-seq [opt]

   Returns TRUE if all went well.  */

static bool
cp_parser_translation_unit (cp_parser* parser)
{
  /* The address of the first non-permanent object on the declarator
     obstack.  */
  static void *declarator_obstack_base;

  bool success;

  /* Create the declarator obstack, if necessary.  */
  if (!cp_error_declarator)
    {
      gcc_obstack_init (&declarator_obstack);
      /* Create the error declarator.  */
      cp_error_declarator = make_declarator (cdk_error);
      /* Create the empty parameter list.  */
      no_parameters = make_parameter_declarator (NULL, NULL, NULL_TREE,
						 UNKNOWN_LOCATION);
      /* Remember where the base of the declarator obstack lies.  */
      declarator_obstack_base = obstack_next_free (&declarator_obstack);
    }

  cp_parser_declaration_seq_opt (parser);

  /* If there are no tokens left then all went well.  */
  if (cp_lexer_next_token_is (parser->lexer, CPP_EOF))
    {
      /* Get rid of the token array; we don't need it any more.  */
      cp_lexer_destroy (parser->lexer);
      parser->lexer = NULL;

      /* This file might have been a context that's implicitly extern
	 "C".  If so, pop the lang context.  (Only relevant for PCH.) */
      if (parser->implicit_extern_c)
	{
	  pop_lang_context ();
	  parser->implicit_extern_c = false;
	}

      /* Finish up.  */
      finish_translation_unit ();

      success = true;
    }
  else
    {
      cp_parser_error (parser, "expected declaration");
      success = false;
    }

  /* Make sure the declarator obstack was fully cleaned up.  */
  gcc_assert (obstack_next_free (&declarator_obstack)
	      == declarator_obstack_base);

  /* All went well.  */
  return success;
}

/* Return the appropriate tsubst flags for parsing, possibly in N3276
   decltype context.  */

static inline tsubst_flags_t
complain_flags (bool decltype_p)
{
  tsubst_flags_t complain = tf_warning_or_error;
  if (decltype_p)
    complain |= tf_decltype;
  return complain;
}

/* We're about to parse a collection of statements.  If we're currently
   parsing tentatively, set up a firewall so that any nested
   cp_parser_commit_to_tentative_parse won't affect the current context.  */

static cp_token_position
cp_parser_start_tentative_firewall (cp_parser *parser)
{
  if (!cp_parser_uncommitted_to_tentative_parse_p (parser))
    return 0;

  cp_parser_parse_tentatively (parser);
  cp_parser_commit_to_topmost_tentative_parse (parser);
  return cp_lexer_token_position (parser->lexer, false);
}

/* We've finished parsing the collection of statements.  Wrap up the
   firewall and replace the relevant tokens with the parsed form.  */

static void
cp_parser_end_tentative_firewall (cp_parser *parser, cp_token_position start,
				  tree expr)
{
  if (!start)
    return;

  /* Finish the firewall level.  */
  cp_parser_parse_definitely (parser);
  /* And remember the result of the parse for when we try again.  */
  cp_token *token = cp_lexer_token_at (parser->lexer, start);
  token->type = CPP_PREPARSED_EXPR;
  token->u.value = expr;
  token->keyword = RID_MAX;
  cp_lexer_purge_tokens_after (parser->lexer, start);
}

/* Like the above functions, but let the user modify the tokens.  Used by
   CPP_DECLTYPE and CPP_TEMPLATE_ID, where we are saving the side-effects for
   later parses, so it makes sense to localize the effects of
   cp_parser_commit_to_tentative_parse.  */

struct tentative_firewall
{
  cp_parser *parser;
  bool set;

  tentative_firewall (cp_parser *p): parser(p)
  {
    /* If we're currently parsing tentatively, start a committed level as a
       firewall and then an inner tentative parse.  */
    if ((set = cp_parser_uncommitted_to_tentative_parse_p (parser)))
      {
	cp_parser_parse_tentatively (parser);
	cp_parser_commit_to_topmost_tentative_parse (parser);
	cp_parser_parse_tentatively (parser);
      }
  }

  ~tentative_firewall()
  {
    if (set)
      {
	/* Finish the inner tentative parse and the firewall, propagating any
	   uncommitted error state to the outer tentative parse.  */
	bool err = cp_parser_error_occurred (parser);
	cp_parser_parse_definitely (parser);
	cp_parser_parse_definitely (parser);
	if (err)
	  cp_parser_simulate_error (parser);
      }
  }
};

/* Some tokens naturally come in pairs e.g.'(' and ')'.
   This class is for tracking such a matching pair of symbols.
   In particular, it tracks the location of the first token,
   so that if the second token is missing, we can highlight the
   location of the first token when notifying the user about the
   problem.  */

template <typename traits_t>
class token_pair
{
 public:
  /* token_pair's ctor.  */
  token_pair () : m_open_loc (UNKNOWN_LOCATION) {}

  /* If the next token is the opening symbol for this pair, consume it and
     return true.
     Otherwise, issue an error and return false.
     In either case, record the location of the opening token.  */

  bool require_open (cp_parser *parser)
  {
    m_open_loc = cp_lexer_peek_token (parser->lexer)->location;
    return cp_parser_require (parser, traits_t::open_token_type,
			      traits_t::required_token_open);
  }

  /* Consume the next token from PARSER, recording its location as
     that of the opening token within the pair.  */

  cp_token * consume_open (cp_parser *parser)
  {
    cp_token *tok = cp_lexer_consume_token (parser->lexer);
    gcc_assert (tok->type == traits_t::open_token_type);
    m_open_loc = tok->location;
    return tok;
  }

  /* If the next token is the closing symbol for this pair, consume it
     and return it.
     Otherwise, issue an error, highlighting the location of the
     corresponding opening token, and return NULL.  */

  cp_token *require_close (cp_parser *parser) const
  {
    return cp_parser_require (parser, traits_t::close_token_type,
			      traits_t::required_token_close,
			      m_open_loc);
  }

 private:
  location_t m_open_loc;
};

/* Traits for token_pair<T> for tracking matching pairs of parentheses.  */

struct matching_paren_traits
{
  static const enum cpp_ttype open_token_type = CPP_OPEN_PAREN;
  static const enum required_token required_token_open  = RT_OPEN_PAREN;
  static const enum cpp_ttype close_token_type = CPP_CLOSE_PAREN;
  static const enum required_token required_token_close = RT_CLOSE_PAREN;
};

/* "matching_parens" is a token_pair<T> class for tracking matching
   pairs of parentheses.  */

typedef token_pair<matching_paren_traits> matching_parens;

/* Traits for token_pair<T> for tracking matching pairs of braces.  */

struct matching_brace_traits
{
  static const enum cpp_ttype open_token_type = CPP_OPEN_BRACE;
  static const enum required_token required_token_open = RT_OPEN_BRACE;
  static const enum cpp_ttype close_token_type = CPP_CLOSE_BRACE;
  static const enum required_token required_token_close = RT_CLOSE_BRACE;
};

/* "matching_braces" is a token_pair<T> class for tracking matching
   pairs of braces.  */

typedef token_pair<matching_brace_traits> matching_braces;


/* Parse a GNU statement-expression, i.e. ({ stmts }), except for the
   enclosing parentheses.  */

static cp_expr
cp_parser_statement_expr (cp_parser *parser)
{
  cp_token_position start = cp_parser_start_tentative_firewall (parser);

  /* Consume the '('.  */
  location_t start_loc = cp_lexer_peek_token (parser->lexer)->location;
  matching_parens parens;
  parens.consume_open (parser);
  /* Start the statement-expression.  */
  tree expr = begin_stmt_expr ();
  /* Parse the compound-statement.  */
  cp_parser_compound_statement (parser, expr, BCS_NORMAL, false);
  /* Finish up.  */
  expr = finish_stmt_expr (expr, false);
  /* Consume the ')'.  */
  location_t finish_loc = cp_lexer_peek_token (parser->lexer)->location;
  if (!parens.require_close (parser))
    cp_parser_skip_to_end_of_statement (parser);

  cp_parser_end_tentative_firewall (parser, start, expr);
  location_t combined_loc = make_location (start_loc, start_loc, finish_loc);
  return cp_expr (expr, combined_loc);
}

/* Expressions [gram.expr] */

/* Parse a fold-operator.

    fold-operator:
        -  *  /  %  ^  &  |  =  <  >  <<  >>
      =  -=  *=  /=  %=  ^=  &=  |=  <<=  >>=
      ==  !=  <=  >=  &&  ||  ,  .*  ->*

   This returns the tree code corresponding to the matched operator
   as an int. When the current token matches a compound assignment
   opertor, the resulting tree code is the negative value of the
   non-assignment operator. */

static int
cp_parser_fold_operator (cp_token *token)
{
  switch (token->type)
    {
    case CPP_PLUS: return PLUS_EXPR;
    case CPP_MINUS: return MINUS_EXPR;
    case CPP_MULT: return MULT_EXPR;
    case CPP_DIV: return TRUNC_DIV_EXPR;
    case CPP_MOD: return TRUNC_MOD_EXPR;
    case CPP_XOR: return BIT_XOR_EXPR;
    case CPP_AND: return BIT_AND_EXPR;
    case CPP_OR: return BIT_IOR_EXPR;
    case CPP_LSHIFT: return LSHIFT_EXPR;
    case CPP_RSHIFT: return RSHIFT_EXPR;

    case CPP_EQ: return -NOP_EXPR;
    case CPP_PLUS_EQ: return -PLUS_EXPR;
    case CPP_MINUS_EQ: return -MINUS_EXPR;
    case CPP_MULT_EQ: return -MULT_EXPR;
    case CPP_DIV_EQ: return -TRUNC_DIV_EXPR;
    case CPP_MOD_EQ: return -TRUNC_MOD_EXPR;
    case CPP_XOR_EQ: return -BIT_XOR_EXPR;
    case CPP_AND_EQ: return -BIT_AND_EXPR;
    case CPP_OR_EQ: return -BIT_IOR_EXPR;
    case CPP_LSHIFT_EQ: return -LSHIFT_EXPR;
    case CPP_RSHIFT_EQ: return -RSHIFT_EXPR;

    case CPP_EQ_EQ: return EQ_EXPR;
    case CPP_NOT_EQ: return NE_EXPR;
    case CPP_LESS: return LT_EXPR;
    case CPP_GREATER: return GT_EXPR;
    case CPP_LESS_EQ: return LE_EXPR;
    case CPP_GREATER_EQ: return GE_EXPR;

    case CPP_AND_AND: return TRUTH_ANDIF_EXPR;
    case CPP_OR_OR: return TRUTH_ORIF_EXPR;

    case CPP_COMMA: return COMPOUND_EXPR;

    case CPP_DOT_STAR: return DOTSTAR_EXPR;
    case CPP_DEREF_STAR: return MEMBER_REF;

    default: return ERROR_MARK;
    }
}

/* Returns true if CODE indicates a binary expression, which is not allowed in
   the LHS of a fold-expression.  More codes will need to be added to use this
   function in other contexts.  */

static bool
is_binary_op (tree_code code)
{
  switch (code)
    {
    case PLUS_EXPR:
    case POINTER_PLUS_EXPR:
    case MINUS_EXPR:
    case MULT_EXPR:
    case TRUNC_DIV_EXPR:
    case TRUNC_MOD_EXPR:
    case BIT_XOR_EXPR:
    case BIT_AND_EXPR:
    case BIT_IOR_EXPR:
    case LSHIFT_EXPR:
    case RSHIFT_EXPR:

    case MODOP_EXPR:

    case EQ_EXPR:
    case NE_EXPR:
    case LE_EXPR:
    case GE_EXPR:
    case LT_EXPR:
    case GT_EXPR:

    case TRUTH_ANDIF_EXPR:
    case TRUTH_ORIF_EXPR:

    case COMPOUND_EXPR:

    case DOTSTAR_EXPR:
    case MEMBER_REF:
      return true;

    default:
      return false;
    }
}

/* If the next token is a suitable fold operator, consume it and return as
   the function above.  */

static int
cp_parser_fold_operator (cp_parser *parser)
{
  cp_token* token = cp_lexer_peek_token (parser->lexer);
  int code = cp_parser_fold_operator (token);
  if (code != ERROR_MARK)
    cp_lexer_consume_token (parser->lexer);
  return code;
}

/* Parse a fold-expression.

     fold-expression:
       ( ... folding-operator cast-expression)
       ( cast-expression folding-operator ... )
       ( cast-expression folding operator ... folding-operator cast-expression)

   Note that the '(' and ')' are matched in primary expression. */

static cp_expr
cp_parser_fold_expression (cp_parser *parser, tree expr1)
{
  cp_id_kind pidk;

  // Left fold.
  if (cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS))
    {
      cp_lexer_consume_token (parser->lexer);
      int op = cp_parser_fold_operator (parser);
      if (op == ERROR_MARK)
        {
          cp_parser_error (parser, "expected binary operator");
          return error_mark_node;
        }

      tree expr = cp_parser_cast_expression (parser, false, false,
					     false, &pidk);
      if (expr == error_mark_node)
        return error_mark_node;
      return finish_left_unary_fold_expr (expr, op);
    }

  const cp_token* token = cp_lexer_peek_token (parser->lexer);
  int op = cp_parser_fold_operator (parser);
  if (op == ERROR_MARK)
    {
      cp_parser_error (parser, "expected binary operator");
      return error_mark_node;
    }

  if (cp_lexer_next_token_is_not (parser->lexer, CPP_ELLIPSIS))
    {
      cp_parser_error (parser, "expected ...");
      return error_mark_node;
    }
  cp_lexer_consume_token (parser->lexer);

  /* The operands of a fold-expression are cast-expressions, so binary or
     conditional expressions are not allowed.  We check this here to avoid
     tentative parsing.  */
  if (EXPR_P (expr1) && TREE_NO_WARNING (expr1))
    /* OK, the expression was parenthesized.  */;
  else if (is_binary_op (TREE_CODE (expr1)))
    error_at (location_of (expr1),
	      "binary expression in operand of fold-expression");
  else if (TREE_CODE (expr1) == COND_EXPR)
    error_at (location_of (expr1),
	      "conditional expression in operand of fold-expression");

  // Right fold.
  if (cp_lexer_next_token_is (parser->lexer, CPP_CLOSE_PAREN))
    return finish_right_unary_fold_expr (expr1, op);

  if (cp_lexer_next_token_is_not (parser->lexer, token->type))
    {
      cp_parser_error (parser, "mismatched operator in fold-expression");
      return error_mark_node;
    }
  cp_lexer_consume_token (parser->lexer);

  // Binary left or right fold.
  tree expr2 = cp_parser_cast_expression (parser, false, false, false, &pidk);
  if (expr2 == error_mark_node)
    return error_mark_node;
  return finish_binary_fold_expr (expr1, expr2, op);
}

/* Parse a primary-expression.

   primary-expression:
     literal
     this
     ( expression )
     id-expression
     lambda-expression (C++11)

   GNU Extensions:

   primary-expression:
     ( compound-statement )
     __builtin_va_arg ( assignment-expression , type-id )
     __builtin_offsetof ( type-id , offsetof-expression )

   C++ Extensions:
     __has_nothrow_assign ( type-id )   
     __has_nothrow_constructor ( type-id )
     __has_nothrow_copy ( type-id )
     __has_trivial_assign ( type-id )   
     __has_trivial_constructor ( type-id )
     __has_trivial_copy ( type-id )
     __has_trivial_destructor ( type-id )
     __has_virtual_destructor ( type-id )     
     __is_abstract ( type-id )
     __is_base_of ( type-id , type-id )
     __is_class ( type-id )
     __is_empty ( type-id )
     __is_enum ( type-id )
     __is_final ( type-id )
     __is_literal_type ( type-id )
     __is_pod ( type-id )
     __is_polymorphic ( type-id )
     __is_std_layout ( type-id )
     __is_trivial ( type-id )
     __is_union ( type-id )

   Objective-C++ Extension:

   primary-expression:
     objc-expression

   literal:
     __null

   ADDRESS_P is true iff this expression was immediately preceded by
   "&" and therefore might denote a pointer-to-member.  CAST_P is true
   iff this expression is the target of a cast.  TEMPLATE_ARG_P is
   true iff this expression is a template argument.

   Returns a representation of the expression.  Upon return, *IDK
   indicates what kind of id-expression (if any) was present.  */

static cp_expr
cp_parser_primary_expression (cp_parser *parser,
			      bool address_p,
			      bool cast_p,
			      bool template_arg_p,
			      bool decltype_p,
			      cp_id_kind *idk)
{
  cp_token *token = NULL;

  /* Assume the primary expression is not an id-expression.  */
  *idk = CP_ID_KIND_NONE;

  /* Peek at the next token.  */
  token = cp_lexer_peek_token (parser->lexer);
  switch ((int) token->type)
    {
      /* literal:
	   integer-literal
	   character-literal
	   floating-literal
	   string-literal
	   boolean-literal
	   pointer-literal
	   user-defined-literal  */
    case CPP_CHAR:
    case CPP_CHAR16:
    case CPP_CHAR32:
    case CPP_WCHAR:
    case CPP_UTF8CHAR:
    case CPP_NUMBER:
    case CPP_PREPARSED_EXPR:
      if (TREE_CODE (token->u.value) == USERDEF_LITERAL)
	return cp_parser_userdef_numeric_literal (parser);
      token = cp_lexer_consume_token (parser->lexer);
      if (TREE_CODE (token->u.value) == FIXED_CST)
	{
	  error_at (token->location,
		    "fixed-point types not supported in C++");
	  return error_mark_node;
	}
      /* Floating-point literals are only allowed in an integral
	 constant expression if they are cast to an integral or
	 enumeration type.  */
      if (TREE_CODE (token->u.value) == REAL_CST
	  && parser->integral_constant_expression_p
	  && pedantic)
	{
	  /* CAST_P will be set even in invalid code like "int(2.7 +
	     ...)".   Therefore, we have to check that the next token
	     is sure to end the cast.  */
	  if (cast_p)
	    {
	      cp_token *next_token;

	      next_token = cp_lexer_peek_token (parser->lexer);
	      if (/* The comma at the end of an
		     enumerator-definition.  */
		  next_token->type != CPP_COMMA
		  /* The curly brace at the end of an enum-specifier.  */
		  && next_token->type != CPP_CLOSE_BRACE
		  /* The end of a statement.  */
		  && next_token->type != CPP_SEMICOLON
		  /* The end of the cast-expression.  */
		  && next_token->type != CPP_CLOSE_PAREN
		  /* The end of an array bound.  */
		  && next_token->type != CPP_CLOSE_SQUARE
		  /* The closing ">" in a template-argument-list.  */
		  && (next_token->type != CPP_GREATER
		      || parser->greater_than_is_operator_p)
		  /* C++0x only: A ">>" treated like two ">" tokens,
                     in a template-argument-list.  */
		  && (next_token->type != CPP_RSHIFT
                      || (cxx_dialect == cxx98)
		      || parser->greater_than_is_operator_p))
		cast_p = false;
	    }

	  /* If we are within a cast, then the constraint that the
	     cast is to an integral or enumeration type will be
	     checked at that point.  If we are not within a cast, then
	     this code is invalid.  */
	  if (!cast_p)
	    cp_parser_non_integral_constant_expression (parser, NIC_FLOAT);
	}
      return cp_expr (token->u.value, token->location);

    case CPP_CHAR_USERDEF:
    case CPP_CHAR16_USERDEF:
    case CPP_CHAR32_USERDEF:
    case CPP_WCHAR_USERDEF:
    case CPP_UTF8CHAR_USERDEF:
      return cp_parser_userdef_char_literal (parser);

    case CPP_STRING:
    case CPP_STRING16:
    case CPP_STRING32:
    case CPP_WSTRING:
    case CPP_UTF8STRING:
    case CPP_STRING_USERDEF:
    case CPP_STRING16_USERDEF:
    case CPP_STRING32_USERDEF:
    case CPP_WSTRING_USERDEF:
    case CPP_UTF8STRING_USERDEF:
      /* ??? Should wide strings be allowed when parser->translate_strings_p
	 is false (i.e. in attributes)?  If not, we can kill the third
	 argument to cp_parser_string_literal.  */
      return cp_parser_string_literal (parser,
				       parser->translate_strings_p,
				       true);

    case CPP_OPEN_PAREN:
      /* If we see `( { ' then we are looking at the beginning of
	 a GNU statement-expression.  */
      if (cp_parser_allow_gnu_extensions_p (parser)
	  && cp_lexer_nth_token_is (parser->lexer, 2, CPP_OPEN_BRACE))
	{
	  /* Statement-expressions are not allowed by the standard.  */
	  pedwarn (token->location, OPT_Wpedantic,
		   "ISO C++ forbids braced-groups within expressions");

	  /* And they're not allowed outside of a function-body; you
	     cannot, for example, write:

	     int i = ({ int j = 3; j + 1; });

	     at class or namespace scope.  */
	  if (!parser->in_function_body
	      || parser->in_template_argument_list_p)
	    {
	      error_at (token->location,
			"statement-expressions are not allowed outside "
			"functions nor in template-argument lists");
	      cp_parser_skip_to_end_of_block_or_statement (parser);
	      if (cp_lexer_next_token_is (parser->lexer, CPP_CLOSE_PAREN))
		cp_lexer_consume_token (parser->lexer);
	      return error_mark_node;
	    }
	  else
	    return cp_parser_statement_expr (parser);
	}
      /* Otherwise it's a normal parenthesized expression.  */
      {
	cp_expr expr;
	bool saved_greater_than_is_operator_p;

	location_t open_paren_loc = token->location;

	/* Consume the `('.  */
	matching_parens parens;
	parens.consume_open (parser);
	/* Within a parenthesized expression, a `>' token is always
	   the greater-than operator.  */
	saved_greater_than_is_operator_p
	  = parser->greater_than_is_operator_p;
	parser->greater_than_is_operator_p = true;

	if (cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS))
	  /* Left fold expression. */
	  expr = NULL_TREE;
	else
	  /* Parse the parenthesized expression.  */
	  expr = cp_parser_expression (parser, idk, cast_p, decltype_p);

	token = cp_lexer_peek_token (parser->lexer);
	if (token->type == CPP_ELLIPSIS || cp_parser_fold_operator (token))
	  {
	    expr = cp_parser_fold_expression (parser, expr);
	    if (expr != error_mark_node
		&& cxx_dialect < cxx17
		&& !in_system_header_at (input_location))
	      pedwarn (input_location, 0, "fold-expressions only available "
		       "with -std=c++17 or -std=gnu++17");
	  }
	else
	  /* Let the front end know that this expression was
	     enclosed in parentheses. This matters in case, for
	     example, the expression is of the form `A::B', since
	     `&A::B' might be a pointer-to-member, but `&(A::B)' is
	     not.  */
	  expr = finish_parenthesized_expr (expr);

	/* DR 705: Wrapping an unqualified name in parentheses
	   suppresses arg-dependent lookup.  We want to pass back
	   CP_ID_KIND_QUALIFIED for suppressing vtable lookup
	   (c++/37862), but none of the others.  */
	if (*idk != CP_ID_KIND_QUALIFIED)
	  *idk = CP_ID_KIND_NONE;

	/* The `>' token might be the end of a template-id or
	   template-parameter-list now.  */
	parser->greater_than_is_operator_p
	  = saved_greater_than_is_operator_p;

	/* Consume the `)'.  */
	token = cp_lexer_peek_token (parser->lexer);
	location_t close_paren_loc = token->location;
	expr.set_range (open_paren_loc, close_paren_loc);
	if (!parens.require_close (parser)
	    && !cp_parser_uncommitted_to_tentative_parse_p (parser))
	  cp_parser_skip_to_end_of_statement (parser);

	return expr;
      }

    case CPP_OPEN_SQUARE:
      {
	if (c_dialect_objc ())
	  {
	    /* We might have an Objective-C++ message. */
	    cp_parser_parse_tentatively (parser);
	    tree msg = cp_parser_objc_message_expression (parser);
	    /* If that works out, we're done ... */
	    if (cp_parser_parse_definitely (parser))
	      return msg;
	    /* ... else, fall though to see if it's a lambda.  */
	  }
	cp_expr lam = cp_parser_lambda_expression (parser);
	/* Don't warn about a failed tentative parse.  */
	if (cp_parser_error_occurred (parser))
	  return error_mark_node;
	maybe_warn_cpp0x (CPP0X_LAMBDA_EXPR);
	return lam;
      }

    case CPP_OBJC_STRING:
      if (c_dialect_objc ())
	/* We have an Objective-C++ string literal. */
        return cp_parser_objc_expression (parser);
      cp_parser_error (parser, "expected primary-expression");
      return error_mark_node;

    case CPP_KEYWORD:
      switch (token->keyword)
	{
	  /* These two are the boolean literals.  */
	case RID_TRUE:
	  cp_lexer_consume_token (parser->lexer);
	  return cp_expr (boolean_true_node, token->location);
	case RID_FALSE:
	  cp_lexer_consume_token (parser->lexer);
	  return cp_expr (boolean_false_node, token->location);

	  /* The `__null' literal.  */
	case RID_NULL:
	  cp_lexer_consume_token (parser->lexer);
	  return cp_expr (null_node, token->location);

	  /* The `nullptr' literal.  */
	case RID_NULLPTR:
	  cp_lexer_consume_token (parser->lexer);
	  return cp_expr (nullptr_node, token->location);

	  /* Recognize the `this' keyword.  */
	case RID_THIS:
	  cp_lexer_consume_token (parser->lexer);
	  if (parser->local_variables_forbidden_p)
	    {
	      error_at (token->location,
			"%<this%> may not be used in this context");
	      return error_mark_node;
	    }
	  /* Pointers cannot appear in constant-expressions.  */
	  if (cp_parser_non_integral_constant_expression (parser, NIC_THIS))
	    return error_mark_node;
	  return cp_expr (finish_this_expr (), token->location);

	  /* The `operator' keyword can be the beginning of an
	     id-expression.  */
	case RID_OPERATOR:
	  goto id_expression;

	case RID_FUNCTION_NAME:
	case RID_PRETTY_FUNCTION_NAME:
	case RID_C99_FUNCTION_NAME:
	  {
	    non_integral_constant name;

	    /* The symbols __FUNCTION__, __PRETTY_FUNCTION__, and
	       __func__ are the names of variables -- but they are
	       treated specially.  Therefore, they are handled here,
	       rather than relying on the generic id-expression logic
	       below.  Grammatically, these names are id-expressions.

	       Consume the token.  */
	    token = cp_lexer_consume_token (parser->lexer);

	    switch (token->keyword)
	      {
	      case RID_FUNCTION_NAME:
		name = NIC_FUNC_NAME;
		break;
	      case RID_PRETTY_FUNCTION_NAME:
		name = NIC_PRETTY_FUNC;
		break;
	      case RID_C99_FUNCTION_NAME:
		name = NIC_C99_FUNC;
		break;
	      default:
		gcc_unreachable ();
	      }

	    if (cp_parser_non_integral_constant_expression (parser, name))
	      return error_mark_node;

	    /* Look up the name.  */
	    return finish_fname (token->u.value);
	  }

	case RID_VA_ARG:
	  {
	    tree expression;
	    tree type;
	    source_location type_location;
	    location_t start_loc
	      = cp_lexer_peek_token (parser->lexer)->location;
	    /* The `__builtin_va_arg' construct is used to handle
	       `va_arg'.  Consume the `__builtin_va_arg' token.  */
	    cp_lexer_consume_token (parser->lexer);
	    /* Look for the opening `('.  */
	    matching_parens parens;
	    parens.require_open (parser);
	    /* Now, parse the assignment-expression.  */
	    expression = cp_parser_assignment_expression (parser);
	    /* Look for the `,'.  */
	    cp_parser_require (parser, CPP_COMMA, RT_COMMA);
	    type_location = cp_lexer_peek_token (parser->lexer)->location;
	    /* Parse the type-id.  */
	    {
	      type_id_in_expr_sentinel s (parser);
	      type = cp_parser_type_id (parser);
	    }
	    /* Look for the closing `)'.  */
	    location_t finish_loc
	      = cp_lexer_peek_token (parser->lexer)->location;
	    parens.require_close (parser);
	    /* Using `va_arg' in a constant-expression is not
	       allowed.  */
	    if (cp_parser_non_integral_constant_expression (parser,
							    NIC_VA_ARG))
	      return error_mark_node;
	    /* Construct a location of the form:
		 __builtin_va_arg (v, int)
		 ~~~~~~~~~~~~~~~~~~~~~^~~~
	       with the caret at the type, ranging from the start of the
	       "__builtin_va_arg" token to the close paren.  */
	    location_t combined_loc
	      = make_location (type_location, start_loc, finish_loc);
	    return build_x_va_arg (combined_loc, expression, type);
	  }

	case RID_OFFSETOF:
	  return cp_parser_builtin_offsetof (parser);

	case RID_HAS_NOTHROW_ASSIGN:
	case RID_HAS_NOTHROW_CONSTRUCTOR:
	case RID_HAS_NOTHROW_COPY:	  
	case RID_HAS_TRIVIAL_ASSIGN:
	case RID_HAS_TRIVIAL_CONSTRUCTOR:
	case RID_HAS_TRIVIAL_COPY:	  
	case RID_HAS_TRIVIAL_DESTRUCTOR:
	case RID_HAS_UNIQUE_OBJ_REPRESENTATIONS:
	case RID_HAS_VIRTUAL_DESTRUCTOR:
	case RID_IS_ABSTRACT:
	case RID_IS_AGGREGATE:
	case RID_IS_BASE_OF:
	case RID_IS_CLASS:
	case RID_IS_EMPTY:
	case RID_IS_ENUM:
	case RID_IS_FINAL:
	case RID_IS_LITERAL_TYPE:
	case RID_IS_POD:
	case RID_IS_POLYMORPHIC:
	case RID_IS_SAME_AS:
	case RID_IS_STD_LAYOUT:
	case RID_IS_TRIVIAL:
	case RID_IS_TRIVIALLY_ASSIGNABLE:
	case RID_IS_TRIVIALLY_CONSTRUCTIBLE:
	case RID_IS_TRIVIALLY_COPYABLE:
	case RID_IS_UNION:
	case RID_IS_ASSIGNABLE:
	case RID_IS_CONSTRUCTIBLE:
	  return cp_parser_trait_expr (parser, token->keyword);

	// C++ concepts
	case RID_REQUIRES:
	  return cp_parser_requires_expression (parser);

	/* Objective-C++ expressions.  */
	case RID_AT_ENCODE:
	case RID_AT_PROTOCOL:
	case RID_AT_SELECTOR:
	  return cp_parser_objc_expression (parser);

	case RID_TEMPLATE:
	  if (parser->in_function_body
	      && (cp_lexer_peek_nth_token (parser->lexer, 2)->type
	      	  == CPP_LESS))
	    {
	      error_at (token->location,
			"a template declaration cannot appear at block scope");
	      cp_parser_skip_to_end_of_block_or_statement (parser);
	      return error_mark_node;
	    }
	  /* FALLTHRU */
	default:
	  cp_parser_error (parser, "expected primary-expression");
	  return error_mark_node;
	}

      /* An id-expression can start with either an identifier, a
	 `::' as the beginning of a qualified-id, or the "operator"
	 keyword.  */
    case CPP_NAME:
    case CPP_SCOPE:
    case CPP_TEMPLATE_ID:
    case CPP_NESTED_NAME_SPECIFIER:
      {
      id_expression:
	cp_expr id_expression;
	cp_expr decl;
	const char *error_msg;
	bool template_p;
	bool done;
	cp_token *id_expr_token;

	/* Parse the id-expression.  */
	id_expression
	  = cp_parser_id_expression (parser,
				     /*template_keyword_p=*/false,
				     /*check_dependency_p=*/true,
				     &template_p,
				     /*declarator_p=*/false,
				     /*optional_p=*/false);
	if (id_expression == error_mark_node)
	  return error_mark_node;
	id_expr_token = token;
	token = cp_lexer_peek_token (parser->lexer);
	done = (token->type != CPP_OPEN_SQUARE
		&& token->type != CPP_OPEN_PAREN
		&& token->type != CPP_DOT
		&& token->type != CPP_DEREF
		&& token->type != CPP_PLUS_PLUS
		&& token->type != CPP_MINUS_MINUS);
	/* If we have a template-id, then no further lookup is
	   required.  If the template-id was for a template-class, we
	   will sometimes have a TYPE_DECL at this point.  */
	if (TREE_CODE (id_expression) == TEMPLATE_ID_EXPR
		 || TREE_CODE (id_expression) == TYPE_DECL)
	  decl = id_expression;
	/* Look up the name.  */
	else
	  {
	    tree ambiguous_decls;

	    /* If we already know that this lookup is ambiguous, then
	       we've already issued an error message; there's no reason
	       to check again.  */
	    if (id_expr_token->type == CPP_NAME
		&& id_expr_token->error_reported)
	      {
		cp_parser_simulate_error (parser);
		return error_mark_node;
	      }

	    decl = cp_parser_lookup_name (parser, id_expression,
					  none_type,
					  template_p,
					  /*is_namespace=*/false,
					  /*check_dependency=*/true,
					  &ambiguous_decls,
					  id_expr_token->location);
	    /* If the lookup was ambiguous, an error will already have
	       been issued.  */
	    if (ambiguous_decls)
	      return error_mark_node;

	    /* In Objective-C++, we may have an Objective-C 2.0
	       dot-syntax for classes here.  */
	    if (c_dialect_objc ()
		&& cp_lexer_peek_token (parser->lexer)->type == CPP_DOT
		&& TREE_CODE (decl) == TYPE_DECL
		&& objc_is_class_name (decl))
	      {
		tree component;
		cp_lexer_consume_token (parser->lexer);
		component = cp_parser_identifier (parser);
		if (component == error_mark_node)
		  return error_mark_node;

		tree result = objc_build_class_component_ref (id_expression,
							      component);
		/* Build a location of the form:
		     expr.component
		     ~~~~~^~~~~~~~~
		   with caret at the start of the component name (at
		   input_location), ranging from the start of the id_expression
		   to the end of the component name.  */
		location_t combined_loc
		  = make_location (input_location, id_expression.get_start (),
				   get_finish (input_location));
		protected_set_expr_location (result, combined_loc);
		return result;
	      }

	    /* In Objective-C++, an instance variable (ivar) may be preferred
	       to whatever cp_parser_lookup_name() found.
	       Call objc_lookup_ivar.  To avoid exposing cp_expr to the
	       rest of c-family, we have to do a little extra work to preserve
	       any location information in cp_expr "decl".  Given that
	       objc_lookup_ivar is implemented in "c-family" and "objc", we
	       have a trip through the pure "tree" type, rather than cp_expr.
	       Naively copying it back to "decl" would implicitly give the
	       new cp_expr value an UNKNOWN_LOCATION for nodes that don't
	       store an EXPR_LOCATION.  Hence we only update "decl" (and
	       hence its location_t) if we get back a different tree node.  */
	    tree decl_tree = objc_lookup_ivar (decl.get_value (),
					       id_expression);
	    if (decl_tree != decl.get_value ())
	      decl = cp_expr (decl_tree);

	    /* If name lookup gives us a SCOPE_REF, then the
	       qualifying scope was dependent.  */
	    if (TREE_CODE (decl) == SCOPE_REF)
	      {
		/* At this point, we do not know if DECL is a valid
		   integral constant expression.  We assume that it is
		   in fact such an expression, so that code like:

		      template <int N> struct A {
			int a[B<N>::i];
		      };
		     
		   is accepted.  At template-instantiation time, we
		   will check that B<N>::i is actually a constant.  */
		return decl;
	      }
	    /* Check to see if DECL is a local variable in a context
	       where that is forbidden.  */
	    if (parser->local_variables_forbidden_p
		&& local_variable_p (decl))
	      {
		/* It might be that we only found DECL because we are
		   trying to be generous with pre-ISO scoping rules.
		   For example, consider:

		     int i;
		     void g() {
		       for (int i = 0; i < 10; ++i) {}
		       extern void f(int j = i);
		     }

		   Here, name look up will originally find the out
		   of scope `i'.  We need to issue a warning message,
		   but then use the global `i'.  */
		decl = check_for_out_of_scope_variable (decl);
		if (local_variable_p (decl))
		  {
		    error_at (id_expr_token->location,
			      "local variable %qD may not appear in this context",
			      decl.get_value ());
		    return error_mark_node;
		  }
	      }
	  }

	decl = (finish_id_expression
		(id_expression, decl, parser->scope,
		 idk,
		 parser->integral_constant_expression_p,
		 parser->allow_non_integral_constant_expression_p,
		 &parser->non_integral_constant_expression_p,
		 template_p, done, address_p,
		 template_arg_p,
		 &error_msg,
		 id_expression.get_location ()));
	if (error_msg)
	  cp_parser_error (parser, error_msg);
	decl.set_location (id_expr_token->location);
	return decl;
      }

      /* Anything else is an error.  */
    default:
      cp_parser_error (parser, "expected primary-expression");
      return error_mark_node;
    }
}

static inline cp_expr
cp_parser_primary_expression (cp_parser *parser,
			      bool address_p,
			      bool cast_p,
			      bool template_arg_p,
			      cp_id_kind *idk)
{
  return cp_parser_primary_expression (parser, address_p, cast_p, template_arg_p,
				       /*decltype*/false, idk);
}

/* Parse an id-expression.

   id-expression:
     unqualified-id
     qualified-id

   qualified-id:
     :: [opt] nested-name-specifier template [opt] unqualified-id
     :: identifier
     :: operator-function-id
     :: template-id

   Return a representation of the unqualified portion of the
   identifier.  Sets PARSER->SCOPE to the qualifying scope if there is
   a `::' or nested-name-specifier.

   Often, if the id-expression was a qualified-id, the caller will
   want to make a SCOPE_REF to represent the qualified-id.  This
   function does not do this in order to avoid wastefully creating
   SCOPE_REFs when they are not required.

   If TEMPLATE_KEYWORD_P is true, then we have just seen the
   `template' keyword.

   If CHECK_DEPENDENCY_P is false, then names are looked up inside
   uninstantiated templates.

   If *TEMPLATE_P is non-NULL, it is set to true iff the
   `template' keyword is used to explicitly indicate that the entity
   named is a template.

   If DECLARATOR_P is true, the id-expression is appearing as part of
   a declarator, rather than as part of an expression.  */

static cp_expr
cp_parser_id_expression (cp_parser *parser,
			 bool template_keyword_p,
			 bool check_dependency_p,
			 bool *template_p,
			 bool declarator_p,
			 bool optional_p)
{
  bool global_scope_p;
  bool nested_name_specifier_p;

  /* Assume the `template' keyword was not used.  */
  if (template_p)
    *template_p = template_keyword_p;

  /* Look for the optional `::' operator.  */
  global_scope_p
    = (!template_keyword_p
       && (cp_parser_global_scope_opt (parser,
				       /*current_scope_valid_p=*/false)
	   != NULL_TREE));

  /* Look for the optional nested-name-specifier.  */
  nested_name_specifier_p
    = (cp_parser_nested_name_specifier_opt (parser,
					    /*typename_keyword_p=*/false,
					    check_dependency_p,
					    /*type_p=*/false,
					    declarator_p,
					    template_keyword_p)
       != NULL_TREE);

  /* If there is a nested-name-specifier, then we are looking at
     the first qualified-id production.  */
  if (nested_name_specifier_p)
    {
      tree saved_scope;
      tree saved_object_scope;
      tree saved_qualifying_scope;
      cp_expr unqualified_id;
      bool is_template;

      /* See if the next token is the `template' keyword.  */
      if (!template_p)
	template_p = &is_template;
      *template_p = cp_parser_optional_template_keyword (parser);
      /* Name lookup we do during the processing of the
	 unqualified-id might obliterate SCOPE.  */
      saved_scope = parser->scope;
      saved_object_scope = parser->object_scope;
      saved_qualifying_scope = parser->qualifying_scope;
      /* Process the final unqualified-id.  */
      unqualified_id = cp_parser_unqualified_id (parser, *template_p,
						 check_dependency_p,
						 declarator_p,
						 /*optional_p=*/false);
      /* Restore the SAVED_SCOPE for our caller.  */
      parser->scope = saved_scope;
      parser->object_scope = saved_object_scope;
      parser->qualifying_scope = saved_qualifying_scope;

      return unqualified_id;
    }
  /* Otherwise, if we are in global scope, then we are looking at one
     of the other qualified-id productions.  */
  else if (global_scope_p)
    {
      cp_token *token;
      tree id;

      /* Peek at the next token.  */
      token = cp_lexer_peek_token (parser->lexer);

      /* If it's an identifier, and the next token is not a "<", then
	 we can avoid the template-id case.  This is an optimization
	 for this common case.  */
      if (token->type == CPP_NAME
	  && !cp_parser_nth_token_starts_template_argument_list_p
	       (parser, 2))
	return cp_parser_identifier (parser);

      cp_parser_parse_tentatively (parser);
      /* Try a template-id.  */
      id = cp_parser_template_id (parser,
				  /*template_keyword_p=*/false,
				  /*check_dependency_p=*/true,
				  none_type,
				  declarator_p);
      /* If that worked, we're done.  */
      if (cp_parser_parse_definitely (parser))
	return id;

      /* Peek at the next token.  (Changes in the token buffer may
	 have invalidated the pointer obtained above.)  */
      token = cp_lexer_peek_token (parser->lexer);

      switch (token->type)
	{
	case CPP_NAME:
	  return cp_parser_identifier (parser);

	case CPP_KEYWORD:
	  if (token->keyword == RID_OPERATOR)
	    return cp_parser_operator_function_id (parser);
	  /* Fall through.  */

	default:
	  cp_parser_error (parser, "expected id-expression");
	  return error_mark_node;
	}
    }
  else
    return cp_parser_unqualified_id (parser, template_keyword_p,
				     /*check_dependency_p=*/true,
				     declarator_p,
				     optional_p);
}

/* Parse an unqualified-id.

   unqualified-id:
     identifier
     operator-function-id
     conversion-function-id
     ~ class-name
     template-id

   If TEMPLATE_KEYWORD_P is TRUE, we have just seen the `template'
   keyword, in a construct like `A::template ...'.

   Returns a representation of unqualified-id.  For the `identifier'
   production, an IDENTIFIER_NODE is returned.  For the `~ class-name'
   production a BIT_NOT_EXPR is returned; the operand of the
   BIT_NOT_EXPR is an IDENTIFIER_NODE for the class-name.  For the
   other productions, see the documentation accompanying the
   corresponding parsing functions.  If CHECK_DEPENDENCY_P is false,
   names are looked up in uninstantiated templates.  If DECLARATOR_P
   is true, the unqualified-id is appearing as part of a declarator,
   rather than as part of an expression.  */

static cp_expr
cp_parser_unqualified_id (cp_parser* parser,
			  bool template_keyword_p,
			  bool check_dependency_p,
			  bool declarator_p,
			  bool optional_p)
{
  cp_token *token;

  /* Peek at the next token.  */
  token = cp_lexer_peek_token (parser->lexer);

  switch ((int) token->type)
    {
    case CPP_NAME:
      {
	tree id;

	/* We don't know yet whether or not this will be a
	   template-id.  */
	cp_parser_parse_tentatively (parser);
	/* Try a template-id.  */
	id = cp_parser_template_id (parser, template_keyword_p,
				    check_dependency_p,
				    none_type,
				    declarator_p);
	/* If it worked, we're done.  */
	if (cp_parser_parse_definitely (parser))
	  return id;
	/* Otherwise, it's an ordinary identifier.  */
	return cp_parser_identifier (parser);
      }

    case CPP_TEMPLATE_ID:
      return cp_parser_template_id (parser, template_keyword_p,
				    check_dependency_p,
				    none_type,
				    declarator_p);

    case CPP_COMPL:
      {
	tree type_decl;
	tree qualifying_scope;
	tree object_scope;
	tree scope;
	bool done;

	/* Consume the `~' token.  */
	cp_lexer_consume_token (parser->lexer);
	/* Parse the class-name.  The standard, as written, seems to
	   say that:

	     template <typename T> struct S { ~S (); };
	     template <typename T> S<T>::~S() {}

	   is invalid, since `~' must be followed by a class-name, but
	   `S<T>' is dependent, and so not known to be a class.
	   That's not right; we need to look in uninstantiated
	   templates.  A further complication arises from:

	     template <typename T> void f(T t) {
	       t.T::~T();
	     }

	   Here, it is not possible to look up `T' in the scope of `T'
	   itself.  We must look in both the current scope, and the
	   scope of the containing complete expression.

	   Yet another issue is:

	     struct S {
	       int S;
	       ~S();
	     };

	     S::~S() {}

	   The standard does not seem to say that the `S' in `~S'
	   should refer to the type `S' and not the data member
	   `S::S'.  */

	/* DR 244 says that we look up the name after the "~" in the
	   same scope as we looked up the qualifying name.  That idea
	   isn't fully worked out; it's more complicated than that.  */
	scope = parser->scope;
	object_scope = parser->object_scope;
	qualifying_scope = parser->qualifying_scope;

	/* Check for invalid scopes.  */
	if (scope == error_mark_node)
	  {
	    if (cp_lexer_next_token_is (parser->lexer, CPP_NAME))
	      cp_lexer_consume_token (parser->lexer);
	    return error_mark_node;
	  }
	if (scope && TREE_CODE (scope) == NAMESPACE_DECL)
	  {
	    if (!cp_parser_uncommitted_to_tentative_parse_p (parser))
	      error_at (token->location,
			"scope %qT before %<~%> is not a class-name",
			scope);
	    cp_parser_simulate_error (parser);
	    if (cp_lexer_next_token_is (parser->lexer, CPP_NAME))
	      cp_lexer_consume_token (parser->lexer);
	    return error_mark_node;
	  }
	gcc_assert (!scope || TYPE_P (scope));

	/* If the name is of the form "X::~X" it's OK even if X is a
	   typedef.  */
	token = cp_lexer_peek_token (parser->lexer);
	if (scope
	    && token->type == CPP_NAME
	    && (cp_lexer_peek_nth_token (parser->lexer, 2)->type
		!= CPP_LESS)
	    && (token->u.value == TYPE_IDENTIFIER (scope)
		|| (CLASS_TYPE_P (scope)
		    && constructor_name_p (token->u.value, scope))))
	  {
	    cp_lexer_consume_token (parser->lexer);
	    return build_nt (BIT_NOT_EXPR, scope);
	  }

	/* ~auto means the destructor of whatever the object is.  */
	if (cp_parser_is_keyword (token, RID_AUTO))
	  {
	    if (cxx_dialect < cxx14)
	      pedwarn (input_location, 0,
		       "%<~auto%> only available with "
		       "-std=c++14 or -std=gnu++14");
	    cp_lexer_consume_token (parser->lexer);
	    return build_nt (BIT_NOT_EXPR, make_auto ());
	  }

	/* If there was an explicit qualification (S::~T), first look
	   in the scope given by the qualification (i.e., S).

	   Note: in the calls to cp_parser_class_name below we pass
	   typename_type so that lookup finds the injected-class-name
	   rather than the constructor.  */
	done = false;
	type_decl = NULL_TREE;
	if (scope)
	  {
	    cp_parser_parse_tentatively (parser);
	    type_decl = cp_parser_class_name (parser,
					      /*typename_keyword_p=*/false,
					      /*template_keyword_p=*/false,
					      typename_type,
					      /*check_dependency=*/false,
					      /*class_head_p=*/false,
					      declarator_p);
	    if (cp_parser_parse_definitely (parser))
	      done = true;
	  }
	/* In "N::S::~S", look in "N" as well.  */
	if (!done && scope && qualifying_scope)
	  {
	    cp_parser_parse_tentatively (parser);
	    parser->scope = qualifying_scope;
	    parser->object_scope = NULL_TREE;
	    parser->qualifying_scope = NULL_TREE;
	    type_decl
	      = cp_parser_class_name (parser,
				      /*typename_keyword_p=*/false,
				      /*template_keyword_p=*/false,
				      typename_type,
				      /*check_dependency=*/false,
				      /*class_head_p=*/false,
				      declarator_p);
	    if (cp_parser_parse_definitely (parser))
	      done = true;
	  }
	/* In "p->S::~T", look in the scope given by "*p" as well.  */
	else if (!done && object_scope)
	  {
	    cp_parser_parse_tentatively (parser);
	    parser->scope = object_scope;
	    parser->object_scope = NULL_TREE;
	    parser->qualifying_scope = NULL_TREE;
	    type_decl
	      = cp_parser_class_name (parser,
				      /*typename_keyword_p=*/false,
				      /*template_keyword_p=*/false,
				      typename_type,
				      /*check_dependency=*/false,
				      /*class_head_p=*/false,
				      declarator_p);
	    if (cp_parser_parse_definitely (parser))
	      done = true;
	  }
	/* Look in the surrounding context.  */
	if (!done)
	  {
	    parser->scope = NULL_TREE;
	    parser->object_scope = NULL_TREE;
	    parser->qualifying_scope = NULL_TREE;
	    if (processing_template_decl)
	      cp_parser_parse_tentatively (parser);
	    type_decl
	      = cp_parser_class_name (parser,
				      /*typename_keyword_p=*/false,
				      /*template_keyword_p=*/false,
				      typename_type,
				      /*check_dependency=*/false,
				      /*class_head_p=*/false,
				      declarator_p);
	    if (processing_template_decl
		&& ! cp_parser_parse_definitely (parser))
	      {
		/* We couldn't find a type with this name.  If we're parsing
		   tentatively, fail and try something else.  */
		if (cp_parser_uncommitted_to_tentative_parse_p (parser))
		  {
		    cp_parser_simulate_error (parser);
		    return error_mark_node;
		  }
		/* Otherwise, accept it and check for a match at instantiation
		   time.  */
		type_decl = cp_parser_identifier (parser);
		if (type_decl != error_mark_node)
		  type_decl = build_nt (BIT_NOT_EXPR, type_decl);
		return type_decl;
	      }
	  }
	/* If an error occurred, assume that the name of the
	   destructor is the same as the name of the qualifying
	   class.  That allows us to keep parsing after running
	   into ill-formed destructor names.  */
	if (type_decl == error_mark_node && scope)
	  return build_nt (BIT_NOT_EXPR, scope);
	else if (type_decl == error_mark_node)
	  return error_mark_node;

	/* Check that destructor name and scope match.  */
	if (declarator_p && scope && !check_dtor_name (scope, type_decl))
	  {
	    if (!cp_parser_uncommitted_to_tentative_parse_p (parser))
	      error_at (token->location,
			"declaration of %<~%T%> as member of %qT",
			type_decl, scope);
	    cp_parser_simulate_error (parser);
	    return error_mark_node;
	  }

	/* [class.dtor]

	   A typedef-name that names a class shall not be used as the
	   identifier in the declarator for a destructor declaration.  */
	if (declarator_p
	    && !DECL_IMPLICIT_TYPEDEF_P (type_decl)
	    && !DECL_SELF_REFERENCE_P (type_decl)
	    && !cp_parser_uncommitted_to_tentative_parse_p (parser))
	  error_at (token->location,
		    "typedef-name %qD used as destructor declarator",
		    type_decl);

	return build_nt (BIT_NOT_EXPR, TREE_TYPE (type_decl));
      }

    case CPP_KEYWORD:
      if (token->keyword == RID_OPERATOR)
	{
	  cp_expr id;

	  /* This could be a template-id, so we try that first.  */
	  cp_parser_parse_tentatively (parser);
	  /* Try a template-id.  */
	  id = cp_parser_template_id (parser, template_keyword_p,
				      /*check_dependency_p=*/true,
				      none_type,
				      declarator_p);
	  /* If that worked, we're done.  */
	  if (cp_parser_parse_definitely (parser))
	    return id;
	  /* We still don't know whether we're looking at an
	     operator-function-id or a conversion-function-id.  */
	  cp_parser_parse_tentatively (parser);
	  /* Try an operator-function-id.  */
	  id = cp_parser_operator_function_id (parser);
	  /* If that didn't work, try a conversion-function-id.  */
	  if (!cp_parser_parse_definitely (parser))
	    id = cp_parser_conversion_function_id (parser);
	  else if (UDLIT_OPER_P (id))
	    {
	      /* 17.6.3.3.5  */
	      const char *name = UDLIT_OP_SUFFIX (id);
	      if (name[0] != '_' && !in_system_header_at (input_location)
		  && declarator_p)
		warning (OPT_Wliteral_suffix,
			 "literal operator suffixes not preceded by %<_%>"
			 " are reserved for future standardization");
	    }

	  return id;
	}
      /* Fall through.  */

    default:
      if (optional_p)
	return NULL_TREE;
      cp_parser_error (parser, "expected unqualified-id");
      return error_mark_node;
    }
}

/* Parse an (optional) nested-name-specifier.

   nested-name-specifier: [C++98]
     class-or-namespace-name :: nested-name-specifier [opt]
     class-or-namespace-name :: template nested-name-specifier [opt]

   nested-name-specifier: [C++0x]
     type-name ::
     namespace-name ::
     nested-name-specifier identifier ::
     nested-name-specifier template [opt] simple-template-id ::

   PARSER->SCOPE should be set appropriately before this function is
   called.  TYPENAME_KEYWORD_P is TRUE if the `typename' keyword is in
   effect.  TYPE_P is TRUE if we non-type bindings should be ignored
   in name lookups.

   Sets PARSER->SCOPE to the class (TYPE) or namespace
   (NAMESPACE_DECL) specified by the nested-name-specifier, or leaves
   it unchanged if there is no nested-name-specifier.  Returns the new
   scope iff there is a nested-name-specifier, or NULL_TREE otherwise.

   If IS_DECLARATION is TRUE, the nested-name-specifier is known to be
   part of a declaration and/or decl-specifier.  */

static tree
cp_parser_nested_name_specifier_opt (cp_parser *parser,
				     bool typename_keyword_p,
				     bool check_dependency_p,
				     bool type_p,
				     bool is_declaration,
				     bool template_keyword_p /* = false */)
{
  bool success = false;
  cp_token_position start = 0;
  cp_token *token;

  /* Remember where the nested-name-specifier starts.  */
  if (cp_parser_uncommitted_to_tentative_parse_p (parser))
    {
      start = cp_lexer_token_position (parser->lexer, false);
      push_deferring_access_checks (dk_deferred);
    }

  while (true)
    {
      tree new_scope;
      tree old_scope;
      tree saved_qualifying_scope;

      /* Spot cases that cannot be the beginning of a
	 nested-name-specifier.  */
      token = cp_lexer_peek_token (parser->lexer);

      /* If the next token is CPP_NESTED_NAME_SPECIFIER, just process
	 the already parsed nested-name-specifier.  */
      if (token->type == CPP_NESTED_NAME_SPECIFIER)
	{
	  /* Grab the nested-name-specifier and continue the loop.  */
	  cp_parser_pre_parsed_nested_name_specifier (parser);
	  /* If we originally encountered this nested-name-specifier
	     with IS_DECLARATION set to false, we will not have
	     resolved TYPENAME_TYPEs, so we must do so here.  */
	  if (is_declaration
	      && TREE_CODE (parser->scope) == TYPENAME_TYPE)
	    {
	      new_scope = resolve_typename_type (parser->scope,
						 /*only_current_p=*/false);
	      if (TREE_CODE (new_scope) != TYPENAME_TYPE)
		parser->scope = new_scope;
	    }
	  success = true;
	  continue;
	}

      /* Spot cases that cannot be the beginning of a
	 nested-name-specifier.  On the second and subsequent times
	 through the loop, we look for the `template' keyword.  */
      if (success && token->keyword == RID_TEMPLATE)
	;
      /* A template-id can start a nested-name-specifier.  */
      else if (token->type == CPP_TEMPLATE_ID)
	;
      /* DR 743: decltype can be used in a nested-name-specifier.  */
      else if (token_is_decltype (token))
	;
      else
	{
	  /* If the next token is not an identifier, then it is
	     definitely not a type-name or namespace-name.  */
	  if (token->type != CPP_NAME)
	    break;
	  /* If the following token is neither a `<' (to begin a
	     template-id), nor a `::', then we are not looking at a
	     nested-name-specifier.  */
	  token = cp_lexer_peek_nth_token (parser->lexer, 2);

	  if (token->type == CPP_COLON
	      && parser->colon_corrects_to_scope_p
	      && cp_lexer_peek_nth_token (parser->lexer, 3)->type == CPP_NAME)
	    {
	      gcc_rich_location richloc (token->location);
	      richloc.add_fixit_replace ("::");
	      error_at_rich_loc (&richloc,
				 "found %<:%> in nested-name-specifier, "
				 "expected %<::%>");
	      token->type = CPP_SCOPE;
	    }

	  if (token->type != CPP_SCOPE
	      && !cp_parser_nth_token_starts_template_argument_list_p
		  (parser, 2))
	    break;
	}

      /* The nested-name-specifier is optional, so we parse
	 tentatively.  */
      cp_parser_parse_tentatively (parser);

      /* Look for the optional `template' keyword, if this isn't the
	 first time through the loop.  */
      if (success)
	template_keyword_p = cp_parser_optional_template_keyword (parser);

      /* Save the old scope since the name lookup we are about to do
	 might destroy it.  */
      old_scope = parser->scope;
      saved_qualifying_scope = parser->qualifying_scope;
      /* In a declarator-id like "X<T>::I::Y<T>" we must be able to
	 look up names in "X<T>::I" in order to determine that "Y" is
	 a template.  So, if we have a typename at this point, we make
	 an effort to look through it.  */
      if (is_declaration
	  && !typename_keyword_p
	  && parser->scope
	  && TREE_CODE (parser->scope) == TYPENAME_TYPE)
	parser->scope = resolve_typename_type (parser->scope,
					       /*only_current_p=*/false);
      /* Parse the qualifying entity.  */
      new_scope
	= cp_parser_qualifying_entity (parser,
                                       typename_keyword_p,
                                       template_keyword_p,
                                       check_dependency_p,
                                       type_p,
                                       is_declaration);
      /* Look for the `::' token.  */
      cp_parser_require (parser, CPP_SCOPE, RT_SCOPE);

      /* If we found what we wanted, we keep going; otherwise, we're
	 done.  */
      if (!cp_parser_parse_definitely (parser))
	{
	  bool error_p = false;

	  /* Restore the OLD_SCOPE since it was valid before the
	     failed attempt at finding the last
	     class-or-namespace-name.  */
	  parser->scope = old_scope;
	  parser->qualifying_scope = saved_qualifying_scope;

	  /* If the next token is a decltype, and the one after that is a
	     `::', then the decltype has failed to resolve to a class or
	     enumeration type.  Give this error even when parsing
	     tentatively since it can't possibly be valid--and we're going
	     to replace it with a CPP_NESTED_NAME_SPECIFIER below, so we
	     won't get another chance.*/
	  if (cp_lexer_next_token_is (parser->lexer, CPP_DECLTYPE)
	      && (cp_lexer_peek_nth_token (parser->lexer, 2)->type
		  == CPP_SCOPE))
	    {
	      token = cp_lexer_consume_token (parser->lexer);
	      error_at (token->location, "decltype evaluates to %qT, "
			"which is not a class or enumeration type",
			token->u.tree_check_value->value);
	      parser->scope = error_mark_node;
	      error_p = true;
	      /* As below.  */
	      success = true;
	      cp_lexer_consume_token (parser->lexer);
	    }

	  if (cp_lexer_next_token_is (parser->lexer, CPP_TEMPLATE_ID)
	      && cp_lexer_nth_token_is (parser->lexer, 2, CPP_SCOPE))
	    {
	      /* If we have a non-type template-id followed by ::, it can't
		 possibly be valid.  */
	      token = cp_lexer_peek_token (parser->lexer);
	      tree tid = token->u.tree_check_value->value;
	      if (TREE_CODE (tid) == TEMPLATE_ID_EXPR
		  && TREE_CODE (TREE_OPERAND (tid, 0)) != IDENTIFIER_NODE)
		{
		  tree tmpl = NULL_TREE;
		  if (is_overloaded_fn (tid))
		    {
		      tree fns = get_fns (tid);
		      if (OVL_SINGLE_P (fns))
			tmpl = OVL_FIRST (fns);
		      error_at (token->location, "function template-id %qD "
				"in nested-name-specifier", tid);
		    }
		  else
		    {
		      /* Variable template.  */
		      tmpl = TREE_OPERAND (tid, 0);
		      gcc_assert (variable_template_p (tmpl));
		      error_at (token->location, "variable template-id %qD "
				"in nested-name-specifier", tid);
		    }
		  if (tmpl)
		    inform (DECL_SOURCE_LOCATION (tmpl),
			    "%qD declared here", tmpl);

		  parser->scope = error_mark_node;
		  error_p = true;
		  /* As below.  */
		  success = true;
		  cp_lexer_consume_token (parser->lexer);
		  cp_lexer_consume_token (parser->lexer);
		}
	    }

	  if (cp_parser_uncommitted_to_tentative_parse_p (parser))
	    break;
	  /* If the next token is an identifier, and the one after
	     that is a `::', then any valid interpretation would have
	     found a class-or-namespace-name.  */
	  while (cp_lexer_next_token_is (parser->lexer, CPP_NAME)
		 && (cp_lexer_peek_nth_token (parser->lexer, 2)->type
		     == CPP_SCOPE)
		 && (cp_lexer_peek_nth_token (parser->lexer, 3)->type
		     != CPP_COMPL))
	    {
	      token = cp_lexer_consume_token (parser->lexer);
	      if (!error_p)
		{
		  if (!token->error_reported)
		    {
		      tree decl;
		      tree ambiguous_decls;

		      decl = cp_parser_lookup_name (parser, token->u.value,
						    none_type,
						    /*is_template=*/false,
						    /*is_namespace=*/false,
						    /*check_dependency=*/true,
						    &ambiguous_decls,
						    token->location);
		      if (TREE_CODE (decl) == TEMPLATE_DECL)
			error_at (token->location,
				  "%qD used without template parameters",
				  decl);
		      else if (ambiguous_decls)
			{
			  // cp_parser_lookup_name has the same diagnostic,
			  // thus make sure to emit it at most once.
			  if (cp_parser_uncommitted_to_tentative_parse_p
			      (parser))
			    {
			      error_at (token->location,
					"reference to %qD is ambiguous",
					token->u.value);
			      print_candidates (ambiguous_decls);
			    }
			  decl = error_mark_node;
			}
		      else
                        {
                          if (cxx_dialect != cxx98)
                            cp_parser_name_lookup_error
                            (parser, token->u.value, decl, NLE_NOT_CXX98,
	  		     token->location);
			  else
			    cp_parser_name_lookup_error
			    (parser, token->u.value, decl, NLE_CXX98,
			     token->location);
                        }
		    }
		  parser->scope = error_mark_node;
		  error_p = true;
		  /* Treat this as a successful nested-name-specifier
		     due to:

		     [basic.lookup.qual]

		     If the name found is not a class-name (clause
		     _class_) or namespace-name (_namespace.def_), the
		     program is ill-formed.  */
		  success = true;
		}
	      cp_lexer_consume_token (parser->lexer);
	    }
	  break;
	}
      /* We've found one valid nested-name-specifier.  */
      success = true;
      /* Name lookup always gives us a DECL.  */
      if (TREE_CODE (new_scope) == TYPE_DECL)
	new_scope = TREE_TYPE (new_scope);
      /* Uses of "template" must be followed by actual templates.  */
      if (template_keyword_p
	  && !(CLASS_TYPE_P (new_scope)
	       && ((CLASSTYPE_USE_TEMPLATE (new_scope)
		    && PRIMARY_TEMPLATE_P (CLASSTYPE_TI_TEMPLATE (new_scope)))
		   || CLASSTYPE_IS_TEMPLATE (new_scope)))
	  && !(TREE_CODE (new_scope) == TYPENAME_TYPE
	       && (TREE_CODE (TYPENAME_TYPE_FULLNAME (new_scope))
		   == TEMPLATE_ID_EXPR)))
	permerror (input_location, TYPE_P (new_scope)
		   ? G_("%qT is not a template")
		   : G_("%qD is not a template"),
		   new_scope);
      /* If it is a class scope, try to complete it; we are about to
	 be looking up names inside the class.  */
      if (TYPE_P (new_scope)
	  /* Since checking types for dependency can be expensive,
	     avoid doing it if the type is already complete.  */
	  && !COMPLETE_TYPE_P (new_scope)
	  /* Do not try to complete dependent types.  */
	  && !dependent_type_p (new_scope))
	{
	  new_scope = complete_type (new_scope);
	  /* If it is a typedef to current class, use the current
	     class instead, as the typedef won't have any names inside
	     it yet.  */
	  if (!COMPLETE_TYPE_P (new_scope)
	      && currently_open_class (new_scope))
	    new_scope = TYPE_MAIN_VARIANT (new_scope);
	}
      /* Make sure we look in the right scope the next time through
	 the loop.  */
      parser->scope = new_scope;
    }

  /* If parsing tentatively, replace the sequence of tokens that makes
     up the nested-name-specifier with a CPP_NESTED_NAME_SPECIFIER
     token.  That way, should we re-parse the token stream, we will
     not have to repeat the effort required to do the parse, nor will
     we issue duplicate error messages.  */
  if (success && start)
    {
      cp_token *token;

      token = cp_lexer_token_at (parser->lexer, start);
      /* Reset the contents of the START token.  */
      token->type = CPP_NESTED_NAME_SPECIFIER;
      /* Retrieve any deferred checks.  Do not pop this access checks yet
	 so the memory will not be reclaimed during token replacing below.  */
      token->u.tree_check_value = ggc_cleared_alloc<struct tree_check> ();
      token->u.tree_check_value->value = parser->scope;
      token->u.tree_check_value->checks = get_deferred_access_checks ();
      token->u.tree_check_value->qualifying_scope =
	parser->qualifying_scope;
      token->keyword = RID_MAX;

      /* Purge all subsequent tokens.  */
      cp_lexer_purge_tokens_after (parser->lexer, start);
    }

  if (start)
    pop_to_parent_deferring_access_checks ();

  return success ? parser->scope : NULL_TREE;
}

/* Parse a nested-name-specifier.  See
   cp_parser_nested_name_specifier_opt for details.  This function
   behaves identically, except that it will an issue an error if no
   nested-name-specifier is present.  */

static tree
cp_parser_nested_name_specifier (cp_parser *parser,
				 bool typename_keyword_p,
				 bool check_dependency_p,
				 bool type_p,
				 bool is_declaration)
{
  tree scope;

  /* Look for the nested-name-specifier.  */
  scope = cp_parser_nested_name_specifier_opt (parser,
					       typename_keyword_p,
					       check_dependency_p,
					       type_p,
					       is_declaration);
  /* If it was not present, issue an error message.  */
  if (!scope)
    {
      cp_parser_error (parser, "expected nested-name-specifier");
      parser->scope = NULL_TREE;
    }

  return scope;
}

/* Parse the qualifying entity in a nested-name-specifier. For C++98,
   this is either a class-name or a namespace-name (which corresponds
   to the class-or-namespace-name production in the grammar). For
   C++0x, it can also be a type-name that refers to an enumeration
   type or a simple-template-id.

   TYPENAME_KEYWORD_P is TRUE iff the `typename' keyword is in effect.
   TEMPLATE_KEYWORD_P is TRUE iff the `template' keyword is in effect.
   CHECK_DEPENDENCY_P is FALSE iff dependent names should be looked up.
   TYPE_P is TRUE iff the next name should be taken as a class-name,
   even the same name is declared to be another entity in the same
   scope.

   Returns the class (TYPE_DECL) or namespace (NAMESPACE_DECL)
   specified by the class-or-namespace-name.  If neither is found the
   ERROR_MARK_NODE is returned.  */

static tree
cp_parser_qualifying_entity (cp_parser *parser,
			     bool typename_keyword_p,
			     bool template_keyword_p,
			     bool check_dependency_p,
			     bool type_p,
			     bool is_declaration)
{
  tree saved_scope;
  tree saved_qualifying_scope;
  tree saved_object_scope;
  tree scope;
  bool only_class_p;
  bool successful_parse_p;

  /* DR 743: decltype can appear in a nested-name-specifier.  */
  if (cp_lexer_next_token_is_decltype (parser->lexer))
    {
      scope = cp_parser_decltype (parser);
      if (TREE_CODE (scope) != ENUMERAL_TYPE
	  && !MAYBE_CLASS_TYPE_P (scope))
	{
	  cp_parser_simulate_error (parser);
	  return error_mark_node;
	}
      if (TYPE_NAME (scope))
	scope = TYPE_NAME (scope);
      return scope;
    }

  /* Before we try to parse the class-name, we must save away the
     current PARSER->SCOPE since cp_parser_class_name will destroy
     it.  */
  saved_scope = parser->scope;
  saved_qualifying_scope = parser->qualifying_scope;
  saved_object_scope = parser->object_scope;
  /* Try for a class-name first.  If the SAVED_SCOPE is a type, then
     there is no need to look for a namespace-name.  */
  only_class_p = template_keyword_p 
    || (saved_scope && TYPE_P (saved_scope) && cxx_dialect == cxx98);
  if (!only_class_p)
    cp_parser_parse_tentatively (parser);
  scope = cp_parser_class_name (parser,
				typename_keyword_p,
				template_keyword_p,
				type_p ? class_type : none_type,
				check_dependency_p,
				/*class_head_p=*/false,
				is_declaration,
				/*enum_ok=*/cxx_dialect > cxx98);
  successful_parse_p = only_class_p || cp_parser_parse_definitely (parser);
  /* If that didn't work, try for a namespace-name.  */
  if (!only_class_p && !successful_parse_p)
    {
      /* Restore the saved scope.  */
      parser->scope = saved_scope;
      parser->qualifying_scope = saved_qualifying_scope;
      parser->object_scope = saved_object_scope;
      /* If we are not looking at an identifier followed by the scope
	 resolution operator, then this is not part of a
	 nested-name-specifier.  (Note that this function is only used
	 to parse the components of a nested-name-specifier.)  */
      if (cp_lexer_next_token_is_not (parser->lexer, CPP_NAME)
	  || cp_lexer_peek_nth_token (parser->lexer, 2)->type != CPP_SCOPE)
	return error_mark_node;
      scope = cp_parser_namespace_name (parser);
    }

  return scope;
}

/* Return true if we are looking at a compound-literal, false otherwise.  */

static bool
cp_parser_compound_literal_p (cp_parser *parser)
{
  cp_lexer_save_tokens (parser->lexer);

  /* Skip tokens until the next token is a closing parenthesis.
     If we find the closing `)', and the next token is a `{', then
     we are looking at a compound-literal.  */
  bool compound_literal_p
    = (cp_parser_skip_to_closing_parenthesis (parser, false, false,
					      /*consume_paren=*/true)
       && cp_lexer_next_token_is (parser->lexer, CPP_OPEN_BRACE));
  
  /* Roll back the tokens we skipped.  */
  cp_lexer_rollback_tokens (parser->lexer);

  return compound_literal_p;
}

/* Parse a postfix-expression.

   postfix-expression:
     primary-expression
     postfix-expression [ expression ]
     postfix-expression ( expression-list [opt] )
     simple-type-specifier ( expression-list [opt] )
     typename :: [opt] nested-name-specifier identifier
       ( expression-list [opt] )
     typename :: [opt] nested-name-specifier template [opt] template-id
       ( expression-list [opt] )
     postfix-expression . template [opt] id-expression
     postfix-expression -> template [opt] id-expression
     postfix-expression . pseudo-destructor-name
     postfix-expression -> pseudo-destructor-name
     postfix-expression ++
     postfix-expression --
     dynamic_cast < type-id > ( expression )
     static_cast < type-id > ( expression )
     reinterpret_cast < type-id > ( expression )
     const_cast < type-id > ( expression )
     typeid ( expression )
     typeid ( type-id )

   GNU Extension:

   postfix-expression:
     ( type-id ) { initializer-list , [opt] }

   This extension is a GNU version of the C99 compound-literal
   construct.  (The C99 grammar uses `type-name' instead of `type-id',
   but they are essentially the same concept.)

   If ADDRESS_P is true, the postfix expression is the operand of the
   `&' operator.  CAST_P is true if this expression is the target of a
   cast.

   If MEMBER_ACCESS_ONLY_P, we only allow postfix expressions that are
   class member access expressions [expr.ref].

   Returns a representation of the expression.  */

static cp_expr
cp_parser_postfix_expression (cp_parser *parser, bool address_p, bool cast_p,
                              bool member_access_only_p, bool decltype_p,
			      cp_id_kind * pidk_return)
{
  cp_token *token;
  location_t loc;
  enum rid keyword;
  cp_id_kind idk = CP_ID_KIND_NONE;
  cp_expr postfix_expression = NULL_TREE;
  bool is_member_access = false;
  int saved_in_statement = -1;

  /* Peek at the next token.  */
  token = cp_lexer_peek_token (parser->lexer);
  loc = token->location;
  location_t start_loc = get_range_from_loc (line_table, loc).m_start;

  /* Some of the productions are determined by keywords.  */
  keyword = token->keyword;
  switch (keyword)
    {
    case RID_DYNCAST:
    case RID_STATCAST:
    case RID_REINTCAST:
    case RID_CONSTCAST:
      {
	tree type;
	cp_expr expression;
	const char *saved_message;
	bool saved_in_type_id_in_expr_p;

	/* All of these can be handled in the same way from the point
	   of view of parsing.  Begin by consuming the token
	   identifying the cast.  */
	cp_lexer_consume_token (parser->lexer);

	/* New types cannot be defined in the cast.  */
	saved_message = parser->type_definition_forbidden_message;
	parser->type_definition_forbidden_message
	  = G_("types may not be defined in casts");

	/* Look for the opening `<'.  */
	cp_parser_require (parser, CPP_LESS, RT_LESS);
	/* Parse the type to which we are casting.  */
	saved_in_type_id_in_expr_p = parser->in_type_id_in_expr_p;
	parser->in_type_id_in_expr_p = true;
	type = cp_parser_type_id (parser);
	parser->in_type_id_in_expr_p = saved_in_type_id_in_expr_p;
	/* Look for the closing `>'.  */
	cp_parser_require (parser, CPP_GREATER, RT_GREATER);
	/* Restore the old message.  */
	parser->type_definition_forbidden_message = saved_message;

	bool saved_greater_than_is_operator_p
	  = parser->greater_than_is_operator_p;
	parser->greater_than_is_operator_p = true;

	/* And the expression which is being cast.  */
	matching_parens parens;
	parens.require_open (parser);
	expression = cp_parser_expression (parser, & idk, /*cast_p=*/true);
	cp_token *close_paren = cp_parser_require (parser, CPP_CLOSE_PAREN,
						   RT_CLOSE_PAREN);
	location_t end_loc = close_paren ?
	  close_paren->location : UNKNOWN_LOCATION;

	parser->greater_than_is_operator_p
	  = saved_greater_than_is_operator_p;

	/* Only type conversions to integral or enumeration types
	   can be used in constant-expressions.  */
	if (!cast_valid_in_integral_constant_expression_p (type)
	    && cp_parser_non_integral_constant_expression (parser, NIC_CAST))
	  {
	    postfix_expression = error_mark_node;
	    break;
	  }

	switch (keyword)
	  {
	  case RID_DYNCAST:
	    postfix_expression
	      = build_dynamic_cast (type, expression, tf_warning_or_error);
	    break;
	  case RID_STATCAST:
	    postfix_expression
	      = build_static_cast (type, expression, tf_warning_or_error);
	    break;
	  case RID_REINTCAST:
	    postfix_expression
	      = build_reinterpret_cast (type, expression, 
                                        tf_warning_or_error);
	    break;
	  case RID_CONSTCAST:
	    postfix_expression
	      = build_const_cast (type, expression, tf_warning_or_error);
	    break;
	  default:
	    gcc_unreachable ();
	  }

	/* Construct a location e.g. :
	     reinterpret_cast <int *> (expr)
	     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	   ranging from the start of the "*_cast" token to the final closing
	   paren, with the caret at the start.  */
	location_t cp_cast_loc = make_location (start_loc, start_loc, end_loc);
	postfix_expression.set_location (cp_cast_loc);
      }
      break;

    case RID_TYPEID:
      {
	tree type;
	const char *saved_message;
	bool saved_in_type_id_in_expr_p;

	/* Consume the `typeid' token.  */
	cp_lexer_consume_token (parser->lexer);
	/* Look for the `(' token.  */
	matching_parens parens;
	parens.require_open (parser);
	/* Types cannot be defined in a `typeid' expression.  */
	saved_message = parser->type_definition_forbidden_message;
	parser->type_definition_forbidden_message
	  = G_("types may not be defined in a %<typeid%> expression");
	/* We can't be sure yet whether we're looking at a type-id or an
	   expression.  */
	cp_parser_parse_tentatively (parser);
	/* Try a type-id first.  */
	saved_in_type_id_in_expr_p = parser->in_type_id_in_expr_p;
	parser->in_type_id_in_expr_p = true;
	type = cp_parser_type_id (parser);
	parser->in_type_id_in_expr_p = saved_in_type_id_in_expr_p;
	/* Look for the `)' token.  Otherwise, we can't be sure that
	   we're not looking at an expression: consider `typeid (int
	   (3))', for example.  */
	cp_token *close_paren = parens.require_close (parser);
	/* If all went well, simply lookup the type-id.  */
	if (cp_parser_parse_definitely (parser))
	  postfix_expression = get_typeid (type, tf_warning_or_error);
	/* Otherwise, fall back to the expression variant.  */
	else
	  {
	    tree expression;

	    /* Look for an expression.  */
	    expression = cp_parser_expression (parser, & idk);
	    /* Compute its typeid.  */
	    postfix_expression = build_typeid (expression, tf_warning_or_error);
	    /* Look for the `)' token.  */
	    close_paren = parens.require_close (parser);
	  }
	/* Restore the saved message.  */
	parser->type_definition_forbidden_message = saved_message;
	/* `typeid' may not appear in an integral constant expression.  */
	if (cp_parser_non_integral_constant_expression (parser, NIC_TYPEID))
	  postfix_expression = error_mark_node;

	/* Construct a location e.g. :
	     typeid (expr)
	     ^~~~~~~~~~~~~
	   ranging from the start of the "typeid" token to the final closing
	   paren, with the caret at the start.  */
	if (close_paren)
	  {
	    location_t typeid_loc
	      = make_location (start_loc, start_loc, close_paren->location);
	    postfix_expression.set_location (typeid_loc);
	  }
      }
      break;

    case RID_TYPENAME:
      {
	tree type;
	/* The syntax permitted here is the same permitted for an
	   elaborated-type-specifier.  */
        ++parser->prevent_constrained_type_specifiers;
	type = cp_parser_elaborated_type_specifier (parser,
						    /*is_friend=*/false,
						    /*is_declaration=*/false);
        --parser->prevent_constrained_type_specifiers;
	postfix_expression = cp_parser_functional_cast (parser, type);
      }
      break;

    case RID_CILK_SPAWN:
      {
	location_t cilk_spawn_loc
	  = cp_lexer_peek_token (parser->lexer)->location;
	cp_lexer_consume_token (parser->lexer);
	token = cp_lexer_peek_token (parser->lexer);
	if (token->type == CPP_SEMICOLON)
	  {
	    error_at (token->location, "%<_Cilk_spawn%> must be followed by "
		      "an expression");
	    postfix_expression = error_mark_node;
	    break;
	  }
	else if (!current_function_decl)
	  {
	    error_at (token->location, "%<_Cilk_spawn%> may only be used "
		      "inside a function");
	    postfix_expression = error_mark_node;
	    break;
	  }
	else
	  {
	    /* Consecutive _Cilk_spawns are not allowed in a statement.  */
	    saved_in_statement = parser->in_statement;
	    parser->in_statement |= IN_CILK_SPAWN;
	  }
	cfun->calls_cilk_spawn = 1;
	postfix_expression = 
	  cp_parser_postfix_expression (parser, false, false, 
					false, false, &idk);
	if (!flag_cilkplus)
	  {
	    error_at (token->location, "-fcilkplus must be enabled to use"
		      " %<_Cilk_spawn%>");
	    cfun->calls_cilk_spawn = 0;
	  }
	else if (saved_in_statement & IN_CILK_SPAWN)
	  {
	    error_at (token->location, "consecutive %<_Cilk_spawn%> keywords "
		      "are not permitted");
	    postfix_expression = error_mark_node;
	    cfun->calls_cilk_spawn = 0; 
	  }
	else
	  {
	    location_t loc = postfix_expression.get_location ();
	    postfix_expression = build_cilk_spawn (token->location, 
						   postfix_expression);
	    /* Build a location of the form:
		 _Cilk_spawn expr
		 ~~~~~~~~~~~~^~~~
	       with caret at the expr, ranging from the start of the
	       _Cilk_spawn token to the end of the expression.  */
	    location_t combined_loc =
	      make_location (loc, cilk_spawn_loc, get_finish (loc));
	    postfix_expression.set_location (combined_loc);
	    if (postfix_expression != error_mark_node) 
	      SET_EXPR_LOCATION (postfix_expression, input_location);
	    parser->in_statement = parser->in_statement & ~IN_CILK_SPAWN;
	  }
	break;
      }

    case RID_ADDRESSOF:
    case RID_BUILTIN_SHUFFLE:
    case RID_BUILTIN_LAUNDER:
      {
	vec<tree, va_gc> *vec;
	unsigned int i;
	tree p;

	cp_lexer_consume_token (parser->lexer);
	vec = cp_parser_parenthesized_expression_list (parser, non_attr,
		    /*cast_p=*/false, /*allow_expansion_p=*/true,
		    /*non_constant_p=*/NULL);
	if (vec == NULL)
	  {
	    postfix_expression = error_mark_node;
	    break;
	  }

	FOR_EACH_VEC_ELT (*vec, i, p)
	  mark_exp_read (p);

	switch (keyword)
	  {
	  case RID_ADDRESSOF:
	    if (vec->length () == 1)
	      postfix_expression
		= cp_build_addressof (loc, (*vec)[0], tf_warning_or_error);
	    else
	      {
		error_at (loc, "wrong number of arguments to "
			       "%<__builtin_addressof%>");
		postfix_expression = error_mark_node;
	      }
	    break;

	  case RID_BUILTIN_LAUNDER:
	    if (vec->length () == 1)
	      postfix_expression = finish_builtin_launder (loc, (*vec)[0],
							   tf_warning_or_error);
	    else
	      {
		error_at (loc, "wrong number of arguments to "
			       "%<__builtin_launder%>");
		postfix_expression = error_mark_node;
	      }
	    break;

	  case RID_BUILTIN_SHUFFLE:
	    if (vec->length () == 2)
	      postfix_expression
		= build_x_vec_perm_expr (loc, (*vec)[0], NULL_TREE,
					 (*vec)[1], tf_warning_or_error);
	    else if (vec->length () == 3)
	      postfix_expression
		= build_x_vec_perm_expr (loc, (*vec)[0], (*vec)[1],
					 (*vec)[2], tf_warning_or_error);
	    else
	      {
		error_at (loc, "wrong number of arguments to "
			       "%<__builtin_shuffle%>");
		postfix_expression = error_mark_node;
	      }
	    break;

	  default:
	    gcc_unreachable ();
	  }
	break;
      }

    default:
      {
	tree type;

	/* If the next thing is a simple-type-specifier, we may be
	   looking at a functional cast.  We could also be looking at
	   an id-expression.  So, we try the functional cast, and if
	   that doesn't work we fall back to the primary-expression.  */
	cp_parser_parse_tentatively (parser);
	/* Look for the simple-type-specifier.  */
        ++parser->prevent_constrained_type_specifiers;
	type = cp_parser_simple_type_specifier (parser,
						/*decl_specs=*/NULL,
						CP_PARSER_FLAGS_NONE);
        --parser->prevent_constrained_type_specifiers;
	/* Parse the cast itself.  */
	if (!cp_parser_error_occurred (parser))
	  postfix_expression
	    = cp_parser_functional_cast (parser, type);
	/* If that worked, we're done.  */
	if (cp_parser_parse_definitely (parser))
	  break;

	/* If the functional-cast didn't work out, try a
	   compound-literal.  */
	if (cp_parser_allow_gnu_extensions_p (parser)
	    && cp_lexer_next_token_is (parser->lexer, CPP_OPEN_PAREN))
	  {
	    cp_expr initializer = NULL_TREE;

	    cp_parser_parse_tentatively (parser);

	    matching_parens parens;
	    parens.consume_open (parser);

	    /* Avoid calling cp_parser_type_id pointlessly, see comment
	       in cp_parser_cast_expression about c++/29234.  */
	    if (!cp_parser_compound_literal_p (parser))
	      cp_parser_simulate_error (parser);
	    else
	      {
		/* Parse the type.  */
		bool saved_in_type_id_in_expr_p = parser->in_type_id_in_expr_p;
		parser->in_type_id_in_expr_p = true;
		type = cp_parser_type_id (parser);
		parser->in_type_id_in_expr_p = saved_in_type_id_in_expr_p;
		parens.require_close (parser);
	      }

	    /* If things aren't going well, there's no need to
	       keep going.  */
	    if (!cp_parser_error_occurred (parser))
	      {
		bool non_constant_p;
		/* Parse the brace-enclosed initializer list.  */
		initializer = cp_parser_braced_list (parser,
						     &non_constant_p);
	      }
	    /* If that worked, we're definitely looking at a
	       compound-literal expression.  */
	    if (cp_parser_parse_definitely (parser))
	      {
		/* Warn the user that a compound literal is not
		   allowed in standard C++.  */
		pedwarn (input_location, OPT_Wpedantic,
			 "ISO C++ forbids compound-literals");
		/* For simplicity, we disallow compound literals in
		   constant-expressions.  We could
		   allow compound literals of integer type, whose
		   initializer was a constant, in constant
		   expressions.  Permitting that usage, as a further
		   extension, would not change the meaning of any
		   currently accepted programs.  (Of course, as
		   compound literals are not part of ISO C++, the
		   standard has nothing to say.)  */
		if (cp_parser_non_integral_constant_expression (parser,
								NIC_NCC))
		  {
		    postfix_expression = error_mark_node;
		    break;
		  }
		/* Form the representation of the compound-literal.  */
		postfix_expression
		  = finish_compound_literal (type, initializer,
					     tf_warning_or_error, fcl_c99);
		postfix_expression.set_location (initializer.get_location ());
		break;
	      }
	  }

	/* It must be a primary-expression.  */
	postfix_expression
	  = cp_parser_primary_expression (parser, address_p, cast_p,
					  /*template_arg_p=*/false,
					  decltype_p,
					  &idk);
      }
      break;
    }

  /* Note that we don't need to worry about calling build_cplus_new on a
     class-valued CALL_EXPR in decltype when it isn't the end of the
     postfix-expression; unary_complex_lvalue will take care of that for
     all these cases.  */

  /* Keep looping until the postfix-expression is complete.  */
  while (true)
    {
      if (idk == CP_ID_KIND_UNQUALIFIED
	  && identifier_p (postfix_expression)
	  && cp_lexer_next_token_is_not (parser->lexer, CPP_OPEN_PAREN))
	/* It is not a Koenig lookup function call.  */
	postfix_expression
	  = unqualified_name_lookup_error (postfix_expression);

      /* Peek at the next token.  */
      token = cp_lexer_peek_token (parser->lexer);

      switch (token->type)
	{
	case CPP_OPEN_SQUARE:
	  if (cp_next_tokens_can_be_std_attribute_p (parser))
	    {
	      cp_parser_error (parser,
			       "two consecutive %<[%> shall "
			       "only introduce an attribute");
	      return error_mark_node;
	    }
	  postfix_expression
	    = cp_parser_postfix_open_square_expression (parser,
							postfix_expression,
							false,
							decltype_p);
	  postfix_expression.set_range (start_loc,
					postfix_expression.get_location ());

	  idk = CP_ID_KIND_NONE;
          is_member_access = false;
	  break;

	case CPP_OPEN_PAREN:
	  /* postfix-expression ( expression-list [opt] ) */
	  {
	    bool koenig_p;
	    bool is_builtin_constant_p;
	    bool saved_integral_constant_expression_p = false;
	    bool saved_non_integral_constant_expression_p = false;
	    tsubst_flags_t complain = complain_flags (decltype_p);
	    vec<tree, va_gc> *args;
	    location_t close_paren_loc = UNKNOWN_LOCATION;

            is_member_access = false;

	    is_builtin_constant_p
	      = DECL_IS_BUILTIN_CONSTANT_P (postfix_expression);
	    if (is_builtin_constant_p)
	      {
		/* The whole point of __builtin_constant_p is to allow
		   non-constant expressions to appear as arguments.  */
		saved_integral_constant_expression_p
		  = parser->integral_constant_expression_p;
		saved_non_integral_constant_expression_p
		  = parser->non_integral_constant_expression_p;
		parser->integral_constant_expression_p = false;
	      }
	    args = (cp_parser_parenthesized_expression_list
		    (parser, non_attr,
		     /*cast_p=*/false, /*allow_expansion_p=*/true,
		     /*non_constant_p=*/NULL,
		     /*close_paren_loc=*/&close_paren_loc));
	    if (is_builtin_constant_p)
	      {
		parser->integral_constant_expression_p
		  = saved_integral_constant_expression_p;
		parser->non_integral_constant_expression_p
		  = saved_non_integral_constant_expression_p;
	      }

	    if (args == NULL)
	      {
		postfix_expression = error_mark_node;
		break;
	      }

	    /* Function calls are not permitted in
	       constant-expressions.  */
	    if (! builtin_valid_in_constant_expr_p (postfix_expression)
		&& cp_parser_non_integral_constant_expression (parser,
							       NIC_FUNC_CALL))
	      {
		postfix_expression = error_mark_node;
		release_tree_vector (args);
		break;
	      }

	    koenig_p = false;
	    if (idk == CP_ID_KIND_UNQUALIFIED
		|| idk == CP_ID_KIND_TEMPLATE_ID)
	      {
		if (identifier_p (postfix_expression))
		  {
		    if (!args->is_empty ())
		      {
			koenig_p = true;
			if (!any_type_dependent_arguments_p (args))
			  postfix_expression
			    = perform_koenig_lookup (postfix_expression, args,
						     complain);
		      }
		    else
		      postfix_expression
			= unqualified_fn_lookup_error (postfix_expression);
		  }
		/* We do not perform argument-dependent lookup if
		   normal lookup finds a non-function, in accordance
		   with the expected resolution of DR 218.  */
		else if (!args->is_empty ()
			 && is_overloaded_fn (postfix_expression))
		  {
		    tree fn = get_first_fn (postfix_expression);
		    fn = STRIP_TEMPLATE (fn);

		    /* Do not do argument dependent lookup if regular
		       lookup finds a member function or a block-scope
		       function declaration.  [basic.lookup.argdep]/3  */
		    if (!DECL_FUNCTION_MEMBER_P (fn)
			&& !DECL_LOCAL_FUNCTION_P (fn))
		      {
			koenig_p = true;
			if (!any_type_dependent_arguments_p (args))
			  postfix_expression
			    = perform_koenig_lookup (postfix_expression, args,
						     complain);
		      }
		  }
	      }

	    if (TREE_CODE (postfix_expression) == FUNCTION_DECL
		&& DECL_BUILT_IN_CLASS (postfix_expression) == BUILT_IN_NORMAL
		&& DECL_FUNCTION_CODE (postfix_expression) == BUILT_IN_MEMSET
		&& vec_safe_length (args) == 3)
	      {
		tree arg0 = (*args)[0];
		tree arg1 = (*args)[1];
		tree arg2 = (*args)[2];
		int literal_mask = ((!!integer_zerop (arg1) << 1)
				    | (!!integer_zerop (arg2) << 2));
		if (TREE_CODE (arg2) == CONST_DECL)
		  arg2 = DECL_INITIAL (arg2);
		warn_for_memset (input_location, arg0, arg2, literal_mask);
	      }

	    if (TREE_CODE (postfix_expression) == COMPONENT_REF)
	      {
		tree instance = TREE_OPERAND (postfix_expression, 0);
		tree fn = TREE_OPERAND (postfix_expression, 1);

		if (processing_template_decl
		    && (type_dependent_object_expression_p (instance)
			|| (!BASELINK_P (fn)
			    && TREE_CODE (fn) != FIELD_DECL)
			|| type_dependent_expression_p (fn)
			|| any_type_dependent_arguments_p (args)))
		  {
		    maybe_generic_this_capture (instance, fn);
		    postfix_expression
		      = build_min_nt_call_vec (postfix_expression, args);
		    release_tree_vector (args);
		    break;
		  }

		if (BASELINK_P (fn))
		  {
		  postfix_expression
		    = (build_new_method_call
		       (instance, fn, &args, NULL_TREE,
			(idk == CP_ID_KIND_QUALIFIED
			 ? LOOKUP_NORMAL|LOOKUP_NONVIRTUAL
			 : LOOKUP_NORMAL),
			/*fn_p=*/NULL,
			complain));
		  }
		else
		  postfix_expression
		    = finish_call_expr (postfix_expression, &args,
					/*disallow_virtual=*/false,
					/*koenig_p=*/false,
					complain);
	      }
	    else if (TREE_CODE (postfix_expression) == OFFSET_REF
		     || TREE_CODE (postfix_expression) == MEMBER_REF
		     || TREE_CODE (postfix_expression) == DOTSTAR_EXPR)
	      postfix_expression = (build_offset_ref_call_from_tree
				    (postfix_expression, &args,
				     complain));
	    else if (idk == CP_ID_KIND_QUALIFIED)
	      /* A call to a static class member, or a namespace-scope
		 function.  */
	      postfix_expression
		= finish_call_expr (postfix_expression, &args,
				    /*disallow_virtual=*/true,
				    koenig_p,
				    complain);
	    else
	      /* All other function calls.  */
	      postfix_expression
		= finish_call_expr (postfix_expression, &args,
				    /*disallow_virtual=*/false,
				    koenig_p,
				    complain);

	    if (close_paren_loc != UNKNOWN_LOCATION)
	      {
		location_t combined_loc = make_location (token->location,
							 start_loc,
							 close_paren_loc);
		postfix_expression.set_location (combined_loc);
	      }

	    /* The POSTFIX_EXPRESSION is certainly no longer an id.  */
	    idk = CP_ID_KIND_NONE;

	    release_tree_vector (args);
	  }
	  break;

	case CPP_DOT:
	case CPP_DEREF:
	  /* postfix-expression . template [opt] id-expression
	     postfix-expression . pseudo-destructor-name
	     postfix-expression -> template [opt] id-expression
	     postfix-expression -> pseudo-destructor-name */

	  /* Consume the `.' or `->' operator.  */
	  cp_lexer_consume_token (parser->lexer);

	  postfix_expression
	    = cp_parser_postfix_dot_deref_expression (parser, token->type,
						      postfix_expression,
						      false, &idk, loc);

          is_member_access = true;
	  break;

	case CPP_PLUS_PLUS:
	  /* postfix-expression ++  */
	  /* Consume the `++' token.  */
	  cp_lexer_consume_token (parser->lexer);
	  /* Generate a representation for the complete expression.  */
	  postfix_expression
	    = finish_increment_expr (postfix_expression,
				     POSTINCREMENT_EXPR);
	  /* Increments may not appear in constant-expressions.  */
	  if (cp_parser_non_integral_constant_expression (parser, NIC_INC))
	    postfix_expression = error_mark_node;
	  idk = CP_ID_KIND_NONE;
          is_member_access = false;
	  break;

	case CPP_MINUS_MINUS:
	  /* postfix-expression -- */
	  /* Consume the `--' token.  */
	  cp_lexer_consume_token (parser->lexer);
	  /* Generate a representation for the complete expression.  */
	  postfix_expression
	    = finish_increment_expr (postfix_expression,
				     POSTDECREMENT_EXPR);
	  /* Decrements may not appear in constant-expressions.  */
	  if (cp_parser_non_integral_constant_expression (parser, NIC_DEC))
	    postfix_expression = error_mark_node;
	  idk = CP_ID_KIND_NONE;
          is_member_access = false;
	  break;

	default:
	  if (pidk_return != NULL)
	    * pidk_return = idk;
          if (member_access_only_p)
            return is_member_access
              ? postfix_expression
              : cp_expr (error_mark_node);
          else
            return postfix_expression;
	}
    }

  /* We should never get here.  */
  gcc_unreachable ();
  return error_mark_node;
}

/* This function parses Cilk Plus array notations.  If a normal array expr. is
   parsed then the array index is passed back to the caller through *INIT_INDEX 
   and the function returns a NULL_TREE.  If array notation expr. is parsed, 
   then *INIT_INDEX is ignored by the caller and the function returns 
   a tree of type ARRAY_NOTATION_REF.  If some error occurred it returns 
   error_mark_node.  */

static tree
cp_parser_array_notation (location_t loc, cp_parser *parser, tree *init_index,
			  tree array_value)
{
  cp_token *token = NULL;
  tree length_index, stride = NULL_TREE, value_tree, array_type;
  if (!array_value || array_value == error_mark_node)
    {
      cp_parser_skip_to_end_of_statement (parser);
      return error_mark_node;
    }

  array_type = TREE_TYPE (array_value);
  
  bool saved_colon_corrects = parser->colon_corrects_to_scope_p;
  parser->colon_corrects_to_scope_p = false;
  token = cp_lexer_peek_token (parser->lexer);
  
  if (!token)
    {
      cp_parser_error (parser, "expected %<:%> or numeral");
      return error_mark_node;
    }
  else if (token->type == CPP_COLON)
    {
      /* Consume the ':'.  */
      cp_lexer_consume_token (parser->lexer);
      
      /* If we are here, then we have a case like this A[:].  */
      if (cp_lexer_peek_token (parser->lexer)->type != CPP_CLOSE_SQUARE)
	{
	  cp_parser_error (parser, "expected %<]%>");
	  cp_parser_skip_to_end_of_statement (parser);
	  return error_mark_node;
	}
      *init_index = NULL_TREE;
      stride = NULL_TREE;
      length_index = NULL_TREE;
    }
  else
    {
      /* If we are here, then there are three valid possibilities:
	 1. ARRAY [ EXP ]
	 2. ARRAY [ EXP : EXP ]
	 3. ARRAY [ EXP : EXP : EXP ]  */

      *init_index = cp_parser_expression (parser);
      if (cp_lexer_peek_token (parser->lexer)->type != CPP_COLON)
	{  
	  /* This indicates that we have a normal array expression.  */
	  parser->colon_corrects_to_scope_p = saved_colon_corrects;
	  return NULL_TREE;
	}
      
      /* Consume the ':'.  */
      cp_lexer_consume_token (parser->lexer);
      length_index = cp_parser_expression (parser);
      if (cp_lexer_peek_token (parser->lexer)->type == CPP_COLON)
	{
	  cp_lexer_consume_token (parser->lexer);
	  stride = cp_parser_expression (parser);
	}
    }
  parser->colon_corrects_to_scope_p = saved_colon_corrects;

  if (*init_index == error_mark_node || length_index == error_mark_node
      || stride == error_mark_node || array_type == error_mark_node)
    {
      if (cp_lexer_peek_token (parser->lexer)->type == CPP_CLOSE_SQUARE)
	cp_lexer_consume_token (parser->lexer);
      return error_mark_node;
    }
  cp_parser_require (parser, CPP_CLOSE_SQUARE, RT_CLOSE_SQUARE);

  value_tree = build_array_notation_ref (loc, array_value, *init_index, 
					 length_index, stride, array_type);
  return value_tree;
}

/* A subroutine of cp_parser_postfix_expression that also gets hijacked
   by cp_parser_builtin_offsetof.  We're looking for

     postfix-expression [ expression ]
     postfix-expression [ braced-init-list ] (C++11)

   FOR_OFFSETOF is set if we're being called in that context, which
   changes how we deal with integer constant expressions.  */

static tree
cp_parser_postfix_open_square_expression (cp_parser *parser,
					  tree postfix_expression,
					  bool for_offsetof,
					  bool decltype_p)
{
  tree index = NULL_TREE;
  location_t loc = cp_lexer_peek_token (parser->lexer)->location;
  bool saved_greater_than_is_operator_p;

  /* Consume the `[' token.  */
  cp_lexer_consume_token (parser->lexer);

  saved_greater_than_is_operator_p = parser->greater_than_is_operator_p;
  parser->greater_than_is_operator_p = true;

  /* Parse the index expression.  */
  /* ??? For offsetof, there is a question of what to allow here.  If
     offsetof is not being used in an integral constant expression context,
     then we *could* get the right answer by computing the value at runtime.
     If we are in an integral constant expression context, then we might
     could accept any constant expression; hard to say without analysis.
     Rather than open the barn door too wide right away, allow only integer
     constant expressions here.  */
  if (for_offsetof)
    index = cp_parser_constant_expression (parser);
  else
    {
      if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_BRACE))
	{
	  bool expr_nonconst_p;
	  cp_lexer_set_source_position (parser->lexer);
	  maybe_warn_cpp0x (CPP0X_INITIALIZER_LISTS);
	  index = cp_parser_braced_list (parser, &expr_nonconst_p);
	  if (flag_cilkplus
	      && cp_lexer_peek_token (parser->lexer)->type == CPP_COLON)
	    {
	      error_at (cp_lexer_peek_token (parser->lexer)->location,
			"braced list index is not allowed with array "
			"notation");
	      cp_parser_skip_to_end_of_statement (parser);
	      return error_mark_node;
	    }
	}
      else if (flag_cilkplus)
	{
	  /* Here are have these two options:
	     ARRAY[EXP : EXP]        - Array notation expr with default
	     stride of 1.
	     ARRAY[EXP : EXP : EXP] - Array Notation with user-defined
	     stride.  */
	  tree an_exp = cp_parser_array_notation (loc, parser, &index, 
						  postfix_expression);
	  if (an_exp)
	    return an_exp;
	}
      else
	index = cp_parser_expression (parser);
    }

  parser->greater_than_is_operator_p = saved_greater_than_is_operator_p;

  /* Look for the closing `]'.  */
  cp_parser_require (parser, CPP_CLOSE_SQUARE, RT_CLOSE_SQUARE);

  /* Build the ARRAY_REF.  */
  postfix_expression = grok_array_decl (loc, postfix_expression,
					index, decltype_p);

  /* When not doing offsetof, array references are not permitted in
     constant-expressions.  */
  if (!for_offsetof
      && (cp_parser_non_integral_constant_expression (parser, NIC_ARRAY_REF)))
    postfix_expression = error_mark_node;

  return postfix_expression;
}

/* A subroutine of cp_parser_postfix_expression that also gets hijacked
   by cp_parser_builtin_offsetof.  We're looking for

     postfix-expression . template [opt] id-expression
     postfix-expression . pseudo-destructor-name
     postfix-expression -> template [opt] id-expression
     postfix-expression -> pseudo-destructor-name

   FOR_OFFSETOF is set if we're being called in that context.  That sorta
   limits what of the above we'll actually accept, but nevermind.
   TOKEN_TYPE is the "." or "->" token, which will already have been
   removed from the stream.  */

static tree
cp_parser_postfix_dot_deref_expression (cp_parser *parser,
					enum cpp_ttype token_type,
					cp_expr postfix_expression,
					bool for_offsetof, cp_id_kind *idk,
					location_t location)
{
  tree name;
  bool dependent_p;
  bool pseudo_destructor_p;
  tree scope = NULL_TREE;
  location_t start_loc = postfix_expression.get_start ();

  /* If this is a `->' operator, dereference the pointer.  */
  if (token_type == CPP_DEREF)
    postfix_expression = build_x_arrow (location, postfix_expression,
					tf_warning_or_error);
  /* Check to see whether or not the expression is type-dependent and
     not the current instantiation.  */
  dependent_p = type_dependent_object_expression_p (postfix_expression);
  /* The identifier following the `->' or `.' is not qualified.  */
  parser->scope = NULL_TREE;
  parser->qualifying_scope = NULL_TREE;
  parser->object_scope = NULL_TREE;
  *idk = CP_ID_KIND_NONE;

  /* Enter the scope corresponding to the type of the object
     given by the POSTFIX_EXPRESSION.  */
  if (!dependent_p)
    {
      scope = TREE_TYPE (postfix_expression);
      /* According to the standard, no expression should ever have
	 reference type.  Unfortunately, we do not currently match
	 the standard in this respect in that our internal representation
	 of an expression may have reference type even when the standard
	 says it does not.  Therefore, we have to manually obtain the
	 underlying type here.  */
      scope = non_reference (scope);
      /* The type of the POSTFIX_EXPRESSION must be complete.  */
      /* Unlike the object expression in other contexts, *this is not
	 required to be of complete type for purposes of class member
	 access (5.2.5) outside the member function body.  */
      if (postfix_expression != current_class_ref
	  && scope != error_mark_node
	  && !(processing_template_decl
	       && current_class_type
	       && (same_type_ignoring_top_level_qualifiers_p
		   (scope, current_class_type))))
	{
	  scope = complete_type (scope);
	  if (!COMPLETE_TYPE_P (scope)
	      /* Avoid clobbering e.g. OVERLOADs or DECLs.  */
	      && EXPR_P (postfix_expression))
	    {
	      /* In a template, be permissive by treating an object expression
		 of incomplete type as dependent (after a pedwarn).  */
	      diagnostic_t kind = (processing_template_decl
				   && MAYBE_CLASS_TYPE_P (scope)
				   ? DK_PEDWARN
				   : DK_ERROR);
	      cxx_incomplete_type_diagnostic
		(location_of (postfix_expression),
		 postfix_expression, scope, kind);
	      if (!MAYBE_CLASS_TYPE_P (scope))
		return error_mark_node;
	      if (processing_template_decl)
		{
		  dependent_p = true;
		  scope = TREE_TYPE (postfix_expression) = NULL_TREE;
		}
	    }
	}

      if (!dependent_p)
	{
	  /* Let the name lookup machinery know that we are processing a
	     class member access expression.  */
	  parser->context->object_type = scope;
	  /* If something went wrong, we want to be able to discern that case,
	     as opposed to the case where there was no SCOPE due to the type
	     of expression being dependent.  */
	  if (!scope)
	    scope = error_mark_node;
	  /* If the SCOPE was erroneous, make the various semantic analysis
	     functions exit quickly -- and without issuing additional error
	     messages.  */
	  if (scope == error_mark_node)
	    postfix_expression = error_mark_node;
	}
    }

  if (dependent_p)
    /* Tell cp_parser_lookup_name that there was an object, even though it's
       type-dependent.  */
    parser->context->object_type = unknown_type_node;

  /* Assume this expression is not a pseudo-destructor access.  */
  pseudo_destructor_p = false;

  /* If the SCOPE is a scalar type, then, if this is a valid program,
     we must be looking at a pseudo-destructor-name.  If POSTFIX_EXPRESSION
     is type dependent, it can be pseudo-destructor-name or something else.
     Try to parse it as pseudo-destructor-name first.  */
  if ((scope && SCALAR_TYPE_P (scope)) || dependent_p)
    {
      tree s;
      tree type;

      cp_parser_parse_tentatively (parser);
      /* Parse the pseudo-destructor-name.  */
      s = NULL_TREE;
      cp_parser_pseudo_destructor_name (parser, postfix_expression,
					&s, &type);
      if (dependent_p
	  && (cp_parser_error_occurred (parser)
	      || !SCALAR_TYPE_P (type)))
	cp_parser_abort_tentative_parse (parser);
      else if (cp_parser_parse_definitely (parser))
	{
	  pseudo_destructor_p = true;
	  postfix_expression
	    = finish_pseudo_destructor_expr (postfix_expression,
					     s, type, location);
	}
    }

  if (!pseudo_destructor_p)
    {
      /* If the SCOPE is not a scalar type, we are looking at an
	 ordinary class member access expression, rather than a
	 pseudo-destructor-name.  */
      bool template_p;
      cp_token *token = cp_lexer_peek_token (parser->lexer);
      /* Parse the id-expression.  */
      name = (cp_parser_id_expression
	      (parser,
	       cp_parser_optional_template_keyword (parser),
	       /*check_dependency_p=*/true,
	       &template_p,
	       /*declarator_p=*/false,
	       /*optional_p=*/false));
      /* In general, build a SCOPE_REF if the member name is qualified.
	 However, if the name was not dependent and has already been
	 resolved; there is no need to build the SCOPE_REF.  For example;

	     struct X { void f(); };
	     template <typename T> void f(T* t) { t->X::f(); }

	 Even though "t" is dependent, "X::f" is not and has been resolved
	 to a BASELINK; there is no need to include scope information.  */

      /* But we do need to remember that there was an explicit scope for
	 virtual function calls.  */
      if (parser->scope)
	*idk = CP_ID_KIND_QUALIFIED;

      /* If the name is a template-id that names a type, we will get a
	 TYPE_DECL here.  That is invalid code.  */
      if (TREE_CODE (name) == TYPE_DECL)
	{
	  error_at (token->location, "invalid use of %qD", name);
	  postfix_expression = error_mark_node;
	}
      else
	{
	  if (name != error_mark_node && !BASELINK_P (name) && parser->scope)
	    {
	      if (TREE_CODE (parser->scope) == NAMESPACE_DECL)
		{
		  error_at (token->location, "%<%D::%D%> is not a class member",
			    parser->scope, name);
		  postfix_expression = error_mark_node;
		}
	      else
		name = build_qualified_name (/*type=*/NULL_TREE,
					     parser->scope,
					     name,
					     template_p);
	      parser->scope = NULL_TREE;
	      parser->qualifying_scope = NULL_TREE;
	      parser->object_scope = NULL_TREE;
	    }
	  if (parser->scope && name && BASELINK_P (name))
	    adjust_result_of_qualified_name_lookup
	      (name, parser->scope, scope);
	  postfix_expression
	    = finish_class_member_access_expr (postfix_expression, name,
					       template_p, 
					       tf_warning_or_error);
	  /* Build a location e.g.:
	       ptr->access_expr
	       ~~~^~~~~~~~~~~~~
	     where the caret is at the deref token, ranging from
	     the start of postfix_expression to the end of the access expr.  */
	  location_t end_loc
	    = get_finish (cp_lexer_previous_token (parser->lexer)->location);
	  location_t combined_loc
	    = make_location (input_location, start_loc, end_loc);
	  protected_set_expr_location (postfix_expression, combined_loc);
	}
    }

  /* We no longer need to look up names in the scope of the object on
     the left-hand side of the `.' or `->' operator.  */
  parser->context->object_type = NULL_TREE;

  /* Outside of offsetof, these operators may not appear in
     constant-expressions.  */
  if (!for_offsetof
      && (cp_parser_non_integral_constant_expression
	  (parser, token_type == CPP_DEREF ? NIC_ARROW : NIC_POINT)))
    postfix_expression = error_mark_node;

  return postfix_expression;
}

/* Parse a parenthesized expression-list.

   expression-list:
     assignment-expression
     expression-list, assignment-expression

   attribute-list:
     expression-list
     identifier
     identifier, expression-list

   CAST_P is true if this expression is the target of a cast.

   ALLOW_EXPANSION_P is true if this expression allows expansion of an
   argument pack.

   Returns a vector of trees.  Each element is a representation of an
   assignment-expression.  NULL is returned if the ( and or ) are
   missing.  An empty, but allocated, vector is returned on no
   expressions.  The parentheses are eaten.  IS_ATTRIBUTE_LIST is id_attr
   if we are parsing an attribute list for an attribute that wants a
   plain identifier argument, normal_attr for an attribute that wants
   an expression, or non_attr if we aren't parsing an attribute list.  If
   NON_CONSTANT_P is non-NULL, *NON_CONSTANT_P indicates whether or
   not all of the expressions in the list were constant.
   If CLOSE_PAREN_LOC is non-NULL, and no errors occur, then *CLOSE_PAREN_LOC
   will be written to with the location of the closing parenthesis.  If
   an error occurs, it may or may not be written to.  */

static vec<tree, va_gc> *
cp_parser_parenthesized_expression_list (cp_parser* parser,
					 int is_attribute_list,
					 bool cast_p,
                                         bool allow_expansion_p,
					 bool *non_constant_p,
					 location_t *close_paren_loc)
{
  vec<tree, va_gc> *expression_list;
  bool fold_expr_p = is_attribute_list != non_attr;
  tree identifier = NULL_TREE;
  bool saved_greater_than_is_operator_p;

  /* Assume all the expressions will be constant.  */
  if (non_constant_p)
    *non_constant_p = false;

  matching_parens parens;
  if (!parens.require_open (parser))
    return NULL;

  expression_list = make_tree_vector ();

  /* Within a parenthesized expression, a `>' token is always
     the greater-than operator.  */
  saved_greater_than_is_operator_p
    = parser->greater_than_is_operator_p;
  parser->greater_than_is_operator_p = true;

  /* Consume expressions until there are no more.  */
  if (cp_lexer_next_token_is_not (parser->lexer, CPP_CLOSE_PAREN))
    while (true)
      {
	tree expr;

	/* At the beginning of attribute lists, check to see if the
	   next token is an identifier.  */
	if (is_attribute_list == id_attr
	    && cp_lexer_peek_token (parser->lexer)->type == CPP_NAME)
	  {
	    cp_token *token;

	    /* Consume the identifier.  */
	    token = cp_lexer_consume_token (parser->lexer);
	    /* Save the identifier.  */
	    identifier = token->u.value;
	  }
	else
	  {
	    bool expr_non_constant_p;

	    /* Parse the next assignment-expression.  */
	    if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_BRACE))
	      {
		/* A braced-init-list.  */
		cp_lexer_set_source_position (parser->lexer);
		maybe_warn_cpp0x (CPP0X_INITIALIZER_LISTS);
		expr = cp_parser_braced_list (parser, &expr_non_constant_p);
		if (non_constant_p && expr_non_constant_p)
		  *non_constant_p = true;
	      }
	    else if (non_constant_p)
	      {
		expr = (cp_parser_constant_expression
			(parser, /*allow_non_constant_p=*/true,
			 &expr_non_constant_p));
		if (expr_non_constant_p)
		  *non_constant_p = true;
	      }
	    else
	      expr = cp_parser_assignment_expression (parser, /*pidk=*/NULL,
						      cast_p);

	    if (fold_expr_p)
	      expr = instantiate_non_dependent_expr (expr);

            /* If we have an ellipsis, then this is an expression
	       expansion.  */
            if (allow_expansion_p
                && cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS))
              {
                /* Consume the `...'.  */
                cp_lexer_consume_token (parser->lexer);

                /* Build the argument pack.  */
                expr = make_pack_expansion (expr);
              }

	     /* Add it to the list.  We add error_mark_node
		expressions to the list, so that we can still tell if
		the correct form for a parenthesized expression-list
		is found. That gives better errors.  */
	    vec_safe_push (expression_list, expr);

	    if (expr == error_mark_node)
	      goto skip_comma;
	  }

	/* After the first item, attribute lists look the same as
	   expression lists.  */
	is_attribute_list = non_attr;

      get_comma:;
	/* If the next token isn't a `,', then we are done.  */
	if (cp_lexer_next_token_is_not (parser->lexer, CPP_COMMA))
	  break;

	/* Otherwise, consume the `,' and keep going.  */
	cp_lexer_consume_token (parser->lexer);
      }

  if (close_paren_loc)
    *close_paren_loc = cp_lexer_peek_token (parser->lexer)->location;

  if (!parens.require_close (parser))
    {
      int ending;

    skip_comma:;
      /* We try and resync to an unnested comma, as that will give the
	 user better diagnostics.  */
      ending = cp_parser_skip_to_closing_parenthesis (parser,
						      /*recovering=*/true,
						      /*or_comma=*/true,
						      /*consume_paren=*/true);
      if (ending < 0)
	goto get_comma;
      if (!ending)
	{
	  parser->greater_than_is_operator_p
	    = saved_greater_than_is_operator_p;
	  return NULL;
	}
    }

  parser->greater_than_is_operator_p
    = saved_greater_than_is_operator_p;

  if (identifier)
    vec_safe_insert (expression_list, 0, identifier);

  return expression_list;
}

/* Parse a pseudo-destructor-name.

   pseudo-destructor-name:
     :: [opt] nested-name-specifier [opt] type-name :: ~ type-name
     :: [opt] nested-name-specifier template template-id :: ~ type-name
     :: [opt] nested-name-specifier [opt] ~ type-name

   If either of the first two productions is used, sets *SCOPE to the
   TYPE specified before the final `::'.  Otherwise, *SCOPE is set to
   NULL_TREE.  *TYPE is set to the TYPE_DECL for the final type-name,
   or ERROR_MARK_NODE if the parse fails.  */

static void
cp_parser_pseudo_destructor_name (cp_parser* parser,
				  tree object,
				  tree* scope,
				  tree* type)
{
  bool nested_name_specifier_p;

  /* Handle ~auto.  */
  if (cp_lexer_next_token_is (parser->lexer, CPP_COMPL)
      && cp_lexer_nth_token_is_keyword (parser->lexer, 2, RID_AUTO)
      && !type_dependent_expression_p (object))
    {
      if (cxx_dialect < cxx14)
	pedwarn (input_location, 0,
		 "%<~auto%> only available with "
		 "-std=c++14 or -std=gnu++14");
      cp_lexer_consume_token (parser->lexer);
      cp_lexer_consume_token (parser->lexer);
      *scope = NULL_TREE;
      *type = TREE_TYPE (object);
      return;
    }

  /* Assume that things will not work out.  */
  *type = error_mark_node;

  /* Look for the optional `::' operator.  */
  cp_parser_global_scope_opt (parser, /*current_scope_valid_p=*/true);
  /* Look for the optional nested-name-specifier.  */
  nested_name_specifier_p
    = (cp_parser_nested_name_specifier_opt (parser,
					    /*typename_keyword_p=*/false,
					    /*check_dependency_p=*/true,
					    /*type_p=*/false,
					    /*is_declaration=*/false)
       != NULL_TREE);
  /* Now, if we saw a nested-name-specifier, we might be doing the
     second production.  */
  if (nested_name_specifier_p
      && cp_lexer_next_token_is_keyword (parser->lexer, RID_TEMPLATE))
    {
      /* Consume the `template' keyword.  */
      cp_lexer_consume_token (parser->lexer);
      /* Parse the template-id.  */
      cp_parser_template_id (parser,
			     /*template_keyword_p=*/true,
			     /*check_dependency_p=*/false,
			     class_type,
			     /*is_declaration=*/true);
      /* Look for the `::' token.  */
      cp_parser_require (parser, CPP_SCOPE, RT_SCOPE);
    }
  /* If the next token is not a `~', then there might be some
     additional qualification.  */
  else if (cp_lexer_next_token_is_not (parser->lexer, CPP_COMPL))
    {
      /* At this point, we're looking for "type-name :: ~".  The type-name
	 must not be a class-name, since this is a pseudo-destructor.  So,
	 it must be either an enum-name, or a typedef-name -- both of which
	 are just identifiers.  So, we peek ahead to check that the "::"
	 and "~" tokens are present; if they are not, then we can avoid
	 calling type_name.  */
      if (cp_lexer_peek_token (parser->lexer)->type != CPP_NAME
	  || cp_lexer_peek_nth_token (parser->lexer, 2)->type != CPP_SCOPE
	  || cp_lexer_peek_nth_token (parser->lexer, 3)->type != CPP_COMPL)
	{
	  cp_parser_error (parser, "non-scalar type");
	  return;
	}

      /* Look for the type-name.  */
      *scope = TREE_TYPE (cp_parser_nonclass_name (parser));
      if (*scope == error_mark_node)
	return;

      /* Look for the `::' token.  */
      cp_parser_require (parser, CPP_SCOPE, RT_SCOPE);
    }
  else
    *scope = NULL_TREE;

  /* Look for the `~'.  */
  cp_parser_require (parser, CPP_COMPL, RT_COMPL);

  /* Once we see the ~, this has to be a pseudo-destructor.  */
  if (!processing_template_decl && !cp_parser_error_occurred (parser))
    cp_parser_commit_to_topmost_tentative_parse (parser);

  /* Look for the type-name again.  We are not responsible for
     checking that it matches the first type-name.  */
  *type = TREE_TYPE (cp_parser_nonclass_name (parser));
}

/* Parse a unary-expression.

   unary-expression:
     postfix-expression
     ++ cast-expression
     -- cast-expression
     unary-operator cast-expression
     sizeof unary-expression
     sizeof ( type-id )
     alignof ( type-id )  [C++0x]
     new-expression
     delete-expression

   GNU Extensions:

   unary-expression:
     __extension__ cast-expression
     __alignof__ unary-expression
     __alignof__ ( type-id )
     alignof unary-expression  [C++0x]
     __real__ cast-expression
     __imag__ cast-expression
     && identifier
     sizeof ( type-id ) { initializer-list , [opt] }
     alignof ( type-id ) { initializer-list , [opt] } [C++0x]
     __alignof__ ( type-id ) { initializer-list , [opt] }

   ADDRESS_P is true iff the unary-expression is appearing as the
   operand of the `&' operator.   CAST_P is true if this expression is
   the target of a cast.

   Returns a representation of the expression.  */

static cp_expr
cp_parser_unary_expression (cp_parser *parser, cp_id_kind * pidk,
			    bool address_p, bool cast_p, bool decltype_p)
{
  cp_token *token;
  enum tree_code unary_operator;

  /* Peek at the next token.  */
  token = cp_lexer_peek_token (parser->lexer);
  /* Some keywords give away the kind of expression.  */
  if (token->type == CPP_KEYWORD)
    {
      enum rid keyword = token->keyword;

      switch (keyword)
	{
	case RID_ALIGNOF:
	case RID_SIZEOF:
	  {
	    tree operand, ret;
	    enum tree_code op;
	    location_t start_loc = token->location;

	    op = keyword == RID_ALIGNOF ? ALIGNOF_EXPR : SIZEOF_EXPR;
	    /* Consume the token.  */
	    cp_lexer_consume_token (parser->lexer);
	    /* Parse the operand.  */
	    operand = cp_parser_sizeof_operand (parser, keyword);

	    if (TYPE_P (operand))
	      ret = cxx_sizeof_or_alignof_type (operand, op, true);
	    else
	      {
		/* ISO C++ defines alignof only with types, not with
		   expressions. So pedwarn if alignof is used with a non-
		   type expression. However, __alignof__ is ok.  */
		if (id_equal (token->u.value, "alignof"))
		  pedwarn (token->location, OPT_Wpedantic,
			   "ISO C++ does not allow %<alignof%> "
			   "with a non-type");

		ret = cxx_sizeof_or_alignof_expr (operand, op, true);
	      }
	    /* For SIZEOF_EXPR, just issue diagnostics, but keep
	       SIZEOF_EXPR with the original operand.  */
	    if (op == SIZEOF_EXPR && ret != error_mark_node)
	      {
		if (TREE_CODE (ret) != SIZEOF_EXPR || TYPE_P (operand))
		  {
		    if (!processing_template_decl && TYPE_P (operand))
		      {
			ret = build_min (SIZEOF_EXPR, size_type_node,
					 build1 (NOP_EXPR, operand,
						 error_mark_node));
			SIZEOF_EXPR_TYPE_P (ret) = 1;
		      }
		    else
		      ret = build_min (SIZEOF_EXPR, size_type_node, operand);
		    TREE_SIDE_EFFECTS (ret) = 0;
		    TREE_READONLY (ret) = 1;
		  }
	      }

	    /* Construct a location e.g. :
	       alignof (expr)
	       ^~~~~~~~~~~~~~
	       with start == caret at the start of the "alignof"/"sizeof"
	       token, with the endpoint at the final closing paren.  */
	    location_t finish_loc
	      = cp_lexer_previous_token (parser->lexer)->location;
	    location_t compound_loc
	      = make_location (start_loc, start_loc, finish_loc);

	    cp_expr ret_expr (ret);
	    ret_expr.set_location (compound_loc);
	    return ret_expr;
	  }

	case RID_NEW:
	  return cp_parser_new_expression (parser);

	case RID_DELETE:
	  return cp_parser_delete_expression (parser);

	case RID_EXTENSION:
	  {
	    /* The saved value of the PEDANTIC flag.  */
	    int saved_pedantic;
	    tree expr;

	    /* Save away the PEDANTIC flag.  */
	    cp_parser_extension_opt (parser, &saved_pedantic);
	    /* Parse the cast-expression.  */
	    expr = cp_parser_simple_cast_expression (parser);
	    /* Restore the PEDANTIC flag.  */
	    pedantic = saved_pedantic;

	    return expr;
	  }

	case RID_REALPART:
	case RID_IMAGPART:
	  {
	    tree expression;

	    /* Consume the `__real__' or `__imag__' token.  */
	    cp_lexer_consume_token (parser->lexer);
	    /* Parse the cast-expression.  */
	    expression = cp_parser_simple_cast_expression (parser);
	    /* Create the complete representation.  */
	    return build_x_unary_op (token->location,
				     (keyword == RID_REALPART
				      ? REALPART_EXPR : IMAGPART_EXPR),
				     expression,
                                     tf_warning_or_error);
	  }
	  break;

	case RID_TRANSACTION_ATOMIC:
	case RID_TRANSACTION_RELAXED:
	  return cp_parser_transaction_expression (parser, keyword);

	case RID_NOEXCEPT:
	  {
	    tree expr;
	    const char *saved_message;
	    bool saved_integral_constant_expression_p;
	    bool saved_non_integral_constant_expression_p;
	    bool saved_greater_than_is_operator_p;

	    cp_lexer_consume_token (parser->lexer);
	    matching_parens parens;
	    parens.require_open (parser);

	    saved_message = parser->type_definition_forbidden_message;
	    parser->type_definition_forbidden_message
	      = G_("types may not be defined in %<noexcept%> expressions");

	    saved_integral_constant_expression_p
	      = parser->integral_constant_expression_p;
	    saved_non_integral_constant_expression_p
	      = parser->non_integral_constant_expression_p;
	    parser->integral_constant_expression_p = false;

	    saved_greater_than_is_operator_p
	      = parser->greater_than_is_operator_p;
	    parser->greater_than_is_operator_p = true;

	    ++cp_unevaluated_operand;
	    ++c_inhibit_evaluation_warnings;
	    ++cp_noexcept_operand;
	    expr = cp_parser_expression (parser);
	    --cp_noexcept_operand;
	    --c_inhibit_evaluation_warnings;
	    --cp_unevaluated_operand;

	    parser->greater_than_is_operator_p
	      = saved_greater_than_is_operator_p;

	    parser->integral_constant_expression_p
	      = saved_integral_constant_expression_p;
	    parser->non_integral_constant_expression_p
	      = saved_non_integral_constant_expression_p;

	    parser->type_definition_forbidden_message = saved_message;

	    parens.require_close (parser);
	    return finish_noexcept_expr (expr, tf_warning_or_error);
	  }

	default:
	  break;
	}
    }

  /* Look for the `:: new' and `:: delete', which also signal the
     beginning of a new-expression, or delete-expression,
     respectively.  If the next token is `::', then it might be one of
     these.  */
  if (cp_lexer_next_token_is (parser->lexer, CPP_SCOPE))
    {
      enum rid keyword;

      /* See if the token after the `::' is one of the keywords in
	 which we're interested.  */
      keyword = cp_lexer_peek_nth_token (parser->lexer, 2)->keyword;
      /* If it's `new', we have a new-expression.  */
      if (keyword == RID_NEW)
	return cp_parser_new_expression (parser);
      /* Similarly, for `delete'.  */
      else if (keyword == RID_DELETE)
	return cp_parser_delete_expression (parser);
    }

  /* Look for a unary operator.  */
  unary_operator = cp_parser_unary_operator (token);
  /* The `++' and `--' operators can be handled similarly, even though
     they are not technically unary-operators in the grammar.  */
  if (unary_operator == ERROR_MARK)
    {
      if (token->type == CPP_PLUS_PLUS)
	unary_operator = PREINCREMENT_EXPR;
      else if (token->type == CPP_MINUS_MINUS)
	unary_operator = PREDECREMENT_EXPR;
      /* Handle the GNU address-of-label extension.  */
      else if (cp_parser_allow_gnu_extensions_p (parser)
	       && token->type == CPP_AND_AND)
	{
	  tree identifier;
	  tree expression;
	  location_t start_loc = token->location;

	  /* Consume the '&&' token.  */
	  cp_lexer_consume_token (parser->lexer);
	  /* Look for the identifier.  */
	  location_t finish_loc
	    = get_finish (cp_lexer_peek_token (parser->lexer)->location);
	  identifier = cp_parser_identifier (parser);
	  /* Construct a location of the form:
	       &&label
	       ^~~~~~~
	     with caret==start at the "&&", finish at the end of the label.  */
	  location_t combined_loc
	    = make_location (start_loc, start_loc, finish_loc);
	  /* Create an expression representing the address.  */
	  expression = finish_label_address_expr (identifier, combined_loc);
	  if (cp_parser_non_integral_constant_expression (parser,
							  NIC_ADDR_LABEL))
	    expression = error_mark_node;
	  return expression;
	}
    }
  if (unary_operator != ERROR_MARK)
    {
      cp_expr cast_expression;
      cp_expr expression = error_mark_node;
      non_integral_constant non_constant_p = NIC_NONE;
      location_t loc = token->location;
      tsubst_flags_t complain = complain_flags (decltype_p);

      /* Consume the operator token.  */
      token = cp_lexer_consume_token (parser->lexer);
      enum cpp_ttype op_ttype = cp_lexer_peek_token (parser->lexer)->type;

      /* Parse the cast-expression.  */
      cast_expression
	= cp_parser_cast_expression (parser,
				     unary_operator == ADDR_EXPR,
				     /*cast_p=*/false,
				     /*decltype*/false,
				     pidk);

      /* Make a location:
	    OP_TOKEN  CAST_EXPRESSION
	    ^~~~~~~~~~~~~~~~~~~~~~~~~
	 with start==caret at the operator token, and
	 extending to the end of the cast_expression.  */
      loc = make_location (loc, loc, cast_expression.get_finish ());

      /* Now, build an appropriate representation.  */
      switch (unary_operator)
	{
	case INDIRECT_REF:
	  non_constant_p = NIC_STAR;
	  expression = build_x_indirect_ref (loc, cast_expression,
					     RO_UNARY_STAR,
                                             complain);
          /* TODO: build_x_indirect_ref does not always honor the
             location, so ensure it is set.  */
          expression.set_location (loc);
	  break;

	case ADDR_EXPR:
	   non_constant_p = NIC_ADDR;
	  /* Fall through.  */
	case BIT_NOT_EXPR:
	  expression = build_x_unary_op (loc, unary_operator,
					 cast_expression,
                                         complain);
          /* TODO: build_x_unary_op does not always honor the location,
             so ensure it is set.  */
          expression.set_location (loc);
	  break;

	case PREINCREMENT_EXPR:
	case PREDECREMENT_EXPR:
	  non_constant_p = unary_operator == PREINCREMENT_EXPR
			   ? NIC_PREINCREMENT : NIC_PREDECREMENT;
	  /* Fall through.  */
	case NEGATE_EXPR:
	  /* Immediately fold negation of a constant, unless the constant is 0
	     (since -0 == 0) or it would overflow.  */
	  if (unary_operator == NEGATE_EXPR && op_ttype == CPP_NUMBER
	      && CONSTANT_CLASS_P (cast_expression)
	      && !integer_zerop (cast_expression)
	      && !TREE_OVERFLOW (cast_expression))
	    {
	      tree folded = fold_build1 (unary_operator,
					 TREE_TYPE (cast_expression),
					 cast_expression);
	      if (CONSTANT_CLASS_P (folded) && !TREE_OVERFLOW (folded))
		{
		  expression = cp_expr (folded, loc);
		  break;
		}
	    }
	  /* Fall through.  */
	case UNARY_PLUS_EXPR:
	case TRUTH_NOT_EXPR:
	  expression = finish_unary_op_expr (loc, unary_operator,
					     cast_expression, complain);
	  break;

	default:
	  gcc_unreachable ();
	}

      if (non_constant_p != NIC_NONE
	  && cp_parser_non_integral_constant_expression (parser,
							 non_constant_p))
	expression = error_mark_node;

      return expression;
    }

  return cp_parser_postfix_expression (parser, address_p, cast_p,
                                       /*member_access_only_p=*/false,
				       decltype_p,
				       pidk);
}

/* Returns ERROR_MARK if TOKEN is not a unary-operator.  If TOKEN is a
   unary-operator, the corresponding tree code is returned.  */

static enum tree_code
cp_parser_unary_operator (cp_token* token)
{
  switch (token->type)
    {
    case CPP_MULT:
      return INDIRECT_REF;

    case CPP_AND:
      return ADDR_EXPR;

    case CPP_PLUS:
      return UNARY_PLUS_EXPR;

    case CPP_MINUS:
      return NEGATE_EXPR;

    case CPP_NOT:
      return TRUTH_NOT_EXPR;

    case CPP_COMPL:
      return BIT_NOT_EXPR;

    default:
      return ERROR_MARK;
    }
}

/* Parse a new-expression.

   new-expression:
     :: [opt] new new-placement [opt] new-type-id new-initializer [opt]
     :: [opt] new new-placement [opt] ( type-id ) new-initializer [opt]

   Returns a representation of the expression.  */

static tree
cp_parser_new_expression (cp_parser* parser)
{
  bool global_scope_p;
  vec<tree, va_gc> *placement;
  tree type;
  vec<tree, va_gc> *initializer;
  tree nelts = NULL_TREE;
  tree ret;

  location_t start_loc = cp_lexer_peek_token (parser->lexer)->location;

  /* Look for the optional `::' operator.  */
  global_scope_p
    = (cp_parser_global_scope_opt (parser,
				   /*current_scope_valid_p=*/false)
       != NULL_TREE);
  /* Look for the `new' operator.  */
  cp_parser_require_keyword (parser, RID_NEW, RT_NEW);
  /* There's no easy way to tell a new-placement from the
     `( type-id )' construct.  */
  cp_parser_parse_tentatively (parser);
  /* Look for a new-placement.  */
  placement = cp_parser_new_placement (parser);
  /* If that didn't work out, there's no new-placement.  */
  if (!cp_parser_parse_definitely (parser))
    {
      if (placement != NULL)
	release_tree_vector (placement);
      placement = NULL;
    }

  /* If the next token is a `(', then we have a parenthesized
     type-id.  */
  if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_PAREN))
    {
      cp_token *token;
      const char *saved_message = parser->type_definition_forbidden_message;

      /* Consume the `('.  */
      matching_parens parens;
      parens.consume_open (parser);

      /* Parse the type-id.  */
      parser->type_definition_forbidden_message
	= G_("types may not be defined in a new-expression");
      {
	type_id_in_expr_sentinel s (parser);
	type = cp_parser_type_id (parser);
      }
      parser->type_definition_forbidden_message = saved_message;

      /* Look for the closing `)'.  */
      parens.require_close (parser);
      token = cp_lexer_peek_token (parser->lexer);
      /* There should not be a direct-new-declarator in this production,
	 but GCC used to allowed this, so we check and emit a sensible error
	 message for this case.  */
      if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_SQUARE))
	{
	  error_at (token->location,
		    "array bound forbidden after parenthesized type-id");
	  inform (token->location, 
		  "try removing the parentheses around the type-id");
	  cp_parser_direct_new_declarator (parser);
	}
    }
  /* Otherwise, there must be a new-type-id.  */
  else
    type = cp_parser_new_type_id (parser, &nelts);

  /* If the next token is a `(' or '{', then we have a new-initializer.  */
  cp_token *token = cp_lexer_peek_token (parser->lexer);
  if (token->type == CPP_OPEN_PAREN
      || token->type == CPP_OPEN_BRACE)
    initializer = cp_parser_new_initializer (parser);
  else
    initializer = NULL;

  /* A new-expression may not appear in an integral constant
     expression.  */
  if (cp_parser_non_integral_constant_expression (parser, NIC_NEW))
    ret = error_mark_node;
  /* 5.3.4/2: "If the auto type-specifier appears in the type-specifier-seq
     of a new-type-id or type-id of a new-expression, the new-expression shall
     contain a new-initializer of the form ( assignment-expression )".
     Additionally, consistently with the spirit of DR 1467, we want to accept
     'new auto { 2 }' too.  */
  else if ((ret = type_uses_auto (type))
	   && !CLASS_PLACEHOLDER_TEMPLATE (ret)
	   && (vec_safe_length (initializer) != 1
	       || (BRACE_ENCLOSED_INITIALIZER_P ((*initializer)[0])
		   && CONSTRUCTOR_NELTS ((*initializer)[0]) != 1)))
    {
      error_at (token->location,
		"initialization of new-expression for type %<auto%> "
		"requires exactly one element");
      ret = error_mark_node;
    }
  else
    {
      /* Construct a location e.g.:
           ptr = new int[100]
                 ^~~~~~~~~~~~
         with caret == start at the start of the "new" token, and the end
         at the end of the final token we consumed.  */
      cp_token *end_tok = cp_lexer_previous_token (parser->lexer);
      location_t end_loc = get_finish (end_tok->location);
      location_t combined_loc = make_location (start_loc, start_loc, end_loc);

      /* Create a representation of the new-expression.  */
      ret = build_new (&placement, type, nelts, &initializer, global_scope_p,
		       tf_warning_or_error);
      protected_set_expr_location (ret, combined_loc);
    }

  if (placement != NULL)
    release_tree_vector (placement);
  if (initializer != NULL)
    release_tree_vector (initializer);

  return ret;
}

/* Parse a new-placement.

   new-placement:
     ( expression-list )

   Returns the same representation as for an expression-list.  */

static vec<tree, va_gc> *
cp_parser_new_placement (cp_parser* parser)
{
  vec<tree, va_gc> *expression_list;

  /* Parse the expression-list.  */
  expression_list = (cp_parser_parenthesized_expression_list
		     (parser, non_attr, /*cast_p=*/false,
		      /*allow_expansion_p=*/true,
		      /*non_constant_p=*/NULL));

  if (expression_list && expression_list->is_empty ())
    error ("expected expression-list or type-id");

  return expression_list;
}

/* Parse a new-type-id.

   new-type-id:
     type-specifier-seq new-declarator [opt]

   Returns the TYPE allocated.  If the new-type-id indicates an array
   type, *NELTS is set to the number of elements in the last array
   bound; the TYPE will not include the last array bound.  */

static tree
cp_parser_new_type_id (cp_parser* parser, tree *nelts)
{
  cp_decl_specifier_seq type_specifier_seq;
  cp_declarator *new_declarator;
  cp_declarator *declarator;
  cp_declarator *outer_declarator;
  const char *saved_message;

  /* The type-specifier sequence must not contain type definitions.
     (It cannot contain declarations of new types either, but if they
     are not definitions we will catch that because they are not
     complete.)  */
  saved_message = parser->type_definition_forbidden_message;
  parser->type_definition_forbidden_message
    = G_("types may not be defined in a new-type-id");
  /* Parse the type-specifier-seq.  */
  cp_parser_type_specifier_seq (parser, /*is_declaration=*/false,
				/*is_trailing_return=*/false,
				&type_specifier_seq);
  /* Restore the old message.  */
  parser->type_definition_forbidden_message = saved_message;

  if (type_specifier_seq.type == error_mark_node)
    return error_mark_node;

  /* Parse the new-declarator.  */
  new_declarator = cp_parser_new_declarator_opt (parser);

  /* Determine the number of elements in the last array dimension, if
     any.  */
  *nelts = NULL_TREE;
  /* Skip down to the last array dimension.  */
  declarator = new_declarator;
  outer_declarator = NULL;
  while (declarator && (declarator->kind == cdk_pointer
			|| declarator->kind == cdk_ptrmem))
    {
      outer_declarator = declarator;
      declarator = declarator->declarator;
    }
  while (declarator
	 && declarator->kind == cdk_array
	 && declarator->declarator
	 && declarator->declarator->kind == cdk_array)
    {
      outer_declarator = declarator;
      declarator = declarator->declarator;
    }

  if (declarator && declarator->kind == cdk_array)
    {
      *nelts = declarator->u.array.bounds;
      if (*nelts == error_mark_node)
	*nelts = integer_one_node;

      if (outer_declarator)
	outer_declarator->declarator = declarator->declarator;
      else
	new_declarator = NULL;
    }

  return groktypename (&type_specifier_seq, new_declarator, false);
}

/* Parse an (optional) new-declarator.

   new-declarator:
     ptr-operator new-declarator [opt]
     direct-new-declarator

   Returns the declarator.  */

static cp_declarator *
cp_parser_new_declarator_opt (cp_parser* parser)
{
  enum tree_code code;
  tree type, std_attributes = NULL_TREE;
  cp_cv_quals cv_quals;  

  /* We don't know if there's a ptr-operator next, or not.  */
  cp_parser_parse_tentatively (parser);
  /* Look for a ptr-operator.  */
  code = cp_parser_ptr_operator (parser, &type, &cv_quals, &std_attributes);
  /* If that worked, look for more new-declarators.  */
  if (cp_parser_parse_definitely (parser))
    {
      cp_declarator *declarator;

      /* Parse another optional declarator.  */
      declarator = cp_parser_new_declarator_opt (parser);

      declarator = cp_parser_make_indirect_declarator
	(code, type, cv_quals, declarator, std_attributes);

      return declarator;
    }

  /* If the next token is a `[', there is a direct-new-declarator.  */
  if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_SQUARE))
    return cp_parser_direct_new_declarator (parser);

  return NULL;
}

/* Parse a direct-new-declarator.

   direct-new-declarator:
     [ expression ]
     direct-new-declarator [constant-expression]

   */

static cp_declarator *
cp_parser_direct_new_declarator (cp_parser* parser)
{
  cp_declarator *declarator = NULL;

  while (true)
    {
      tree expression;
      cp_token *token;

      /* Look for the opening `['.  */
      cp_parser_require (parser, CPP_OPEN_SQUARE, RT_OPEN_SQUARE);

      token = cp_lexer_peek_token (parser->lexer);
      expression = cp_parser_expression (parser);
      /* The standard requires that the expression have integral
	 type.  DR 74 adds enumeration types.  We believe that the
	 real intent is that these expressions be handled like the
	 expression in a `switch' condition, which also allows
	 classes with a single conversion to integral or
	 enumeration type.  */
      if (!processing_template_decl)
	{
	  expression
	    = build_expr_type_conversion (WANT_INT | WANT_ENUM,
					  expression,
					  /*complain=*/true);
	  if (!expression)
	    {
	      error_at (token->location,
			"expression in new-declarator must have integral "
			"or enumeration type");
	      expression = error_mark_node;
	    }
	}

      /* Look for the closing `]'.  */
      cp_parser_require (parser, CPP_CLOSE_SQUARE, RT_CLOSE_SQUARE);

      /* Add this bound to the declarator.  */
      declarator = make_array_declarator (declarator, expression);

      /* If the next token is not a `[', then there are no more
	 bounds.  */
      if (cp_lexer_next_token_is_not (parser->lexer, CPP_OPEN_SQUARE))
	break;
    }

  return declarator;
}

/* Parse a new-initializer.

   new-initializer:
     ( expression-list [opt] )
     braced-init-list

   Returns a representation of the expression-list.  */

static vec<tree, va_gc> *
cp_parser_new_initializer (cp_parser* parser)
{
  vec<tree, va_gc> *expression_list;

  if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_BRACE))
    {
      tree t;
      bool expr_non_constant_p;
      cp_lexer_set_source_position (parser->lexer);
      maybe_warn_cpp0x (CPP0X_INITIALIZER_LISTS);
      t = cp_parser_braced_list (parser, &expr_non_constant_p);
      CONSTRUCTOR_IS_DIRECT_INIT (t) = 1;
      expression_list = make_tree_vector_single (t);
    }
  else
    expression_list = (cp_parser_parenthesized_expression_list
		       (parser, non_attr, /*cast_p=*/false,
			/*allow_expansion_p=*/true,
			/*non_constant_p=*/NULL));

  return expression_list;
}

/* Parse a delete-expression.

   delete-expression:
     :: [opt] delete cast-expression
     :: [opt] delete [ ] cast-expression

   Returns a representation of the expression.  */

static tree
cp_parser_delete_expression (cp_parser* parser)
{
  bool global_scope_p;
  bool array_p;
  tree expression;

  /* Look for the optional `::' operator.  */
  global_scope_p
    = (cp_parser_global_scope_opt (parser,
				   /*current_scope_valid_p=*/false)
       != NULL_TREE);
  /* Look for the `delete' keyword.  */
  cp_parser_require_keyword (parser, RID_DELETE, RT_DELETE);
  /* See if the array syntax is in use.  */
  if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_SQUARE))
    {
      /* Consume the `[' token.  */
      cp_lexer_consume_token (parser->lexer);
      /* Look for the `]' token.  */
      cp_parser_require (parser, CPP_CLOSE_SQUARE, RT_CLOSE_SQUARE);
      /* Remember that this is the `[]' construct.  */
      array_p = true;
    }
  else
    array_p = false;

  /* Parse the cast-expression.  */
  expression = cp_parser_simple_cast_expression (parser);

  /* A delete-expression may not appear in an integral constant
     expression.  */
  if (cp_parser_non_integral_constant_expression (parser, NIC_DEL))
    return error_mark_node;

  return delete_sanity (expression, NULL_TREE, array_p, global_scope_p,
			tf_warning_or_error);
}

/* Returns 1 if TOKEN may start a cast-expression and isn't '++', '--',
   neither '[' in C++11; -1 if TOKEN is '++', '--', or '[' in C++11;
   0 otherwise.  */

static int
cp_parser_tokens_start_cast_expression (cp_parser *parser)
{
  cp_token *token = cp_lexer_peek_token (parser->lexer);
  switch (token->type)
    {
    case CPP_COMMA:
    case CPP_SEMICOLON:
    case CPP_QUERY:
    case CPP_COLON:
    case CPP_CLOSE_SQUARE:
    case CPP_CLOSE_PAREN:
    case CPP_CLOSE_BRACE:
    case CPP_OPEN_BRACE:
    case CPP_DOT:
    case CPP_DOT_STAR:
    case CPP_DEREF:
    case CPP_DEREF_STAR:
    case CPP_DIV:
    case CPP_MOD:
    case CPP_LSHIFT:
    case CPP_RSHIFT:
    case CPP_LESS:
    case CPP_GREATER:
    case CPP_LESS_EQ:
    case CPP_GREATER_EQ:
    case CPP_EQ_EQ:
    case CPP_NOT_EQ:
    case CPP_EQ:
    case CPP_MULT_EQ:
    case CPP_DIV_EQ:
    case CPP_MOD_EQ:
    case CPP_PLUS_EQ:
    case CPP_MINUS_EQ:
    case CPP_RSHIFT_EQ:
    case CPP_LSHIFT_EQ:
    case CPP_AND_EQ:
    case CPP_XOR_EQ:
    case CPP_OR_EQ:
    case CPP_XOR:
    case CPP_OR:
    case CPP_OR_OR:
    case CPP_EOF:
    case CPP_ELLIPSIS:
      return 0;

    case CPP_OPEN_PAREN:
      /* In ((type ()) () the last () isn't a valid cast-expression,
	 so the whole must be parsed as postfix-expression.  */
      return cp_lexer_peek_nth_token (parser->lexer, 2)->type
	     != CPP_CLOSE_PAREN;

    case CPP_OPEN_SQUARE:
      /* '[' may start a primary-expression in obj-c++ and in C++11,
	 as a lambda-expression, eg, '(void)[]{}'.  */
      if (cxx_dialect >= cxx11)
	return -1;
      return c_dialect_objc ();

    case CPP_PLUS_PLUS:
    case CPP_MINUS_MINUS:
      /* '++' and '--' may or may not start a cast-expression:

	 struct T { void operator++(int); };
	 void f() { (T())++; }

	 vs

	 int a;
	 (int)++a;  */
      return -1;

    default:
      return 1;
    }
}

/* Try to find a legal C++-style cast to DST_TYPE for ORIG_EXPR, trying them
   in the order: const_cast, static_cast, reinterpret_cast.

   Don't suggest dynamic_cast.

   Return the first legal cast kind found, or NULL otherwise.  */

static const char *
get_cast_suggestion (tree dst_type, tree orig_expr)
{
  tree trial;

  /* Reuse the parser logic by attempting to build the various kinds of
     cast, with "complain" disabled.
     Identify the first such cast that is valid.  */

  /* Don't attempt to run such logic within template processing.  */
  if (processing_template_decl)
    return NULL;

  /* First try const_cast.  */
  trial = build_const_cast (dst_type, orig_expr, tf_none);
  if (trial != error_mark_node)
    return "const_cast";

  /* If that fails, try static_cast.  */
  trial = build_static_cast (dst_type, orig_expr, tf_none);
  if (trial != error_mark_node)
    return "static_cast";

  /* Finally, try reinterpret_cast.  */
  trial = build_reinterpret_cast (dst_type, orig_expr, tf_none);
  if (trial != error_mark_node)
    return "reinterpret_cast";

  /* No such cast possible.  */
  return NULL;
}

/* If -Wold-style-cast is enabled, add fix-its to RICHLOC,
   suggesting how to convert a C-style cast of the form:

     (DST_TYPE)ORIG_EXPR

   to a C++-style cast.

   The primary range of RICHLOC is asssumed to be that of the original
   expression.  OPEN_PAREN_LOC and CLOSE_PAREN_LOC give the locations
   of the parens in the C-style cast.  */

static void
maybe_add_cast_fixit (rich_location *rich_loc, location_t open_paren_loc,
		      location_t close_paren_loc, tree orig_expr,
		      tree dst_type)
{
  /* This function is non-trivial, so bail out now if the warning isn't
     going to be emitted.  */
  if (!warn_old_style_cast)
    return;

  /* Try to find a legal C++ cast, trying them in order:
     const_cast, static_cast, reinterpret_cast.  */
  const char *cast_suggestion = get_cast_suggestion (dst_type, orig_expr);
  if (!cast_suggestion)
    return;

  /* Replace the open paren with "CAST_SUGGESTION<".  */
  pretty_printer pp;
  pp_printf (&pp, "%s<", cast_suggestion);
  rich_loc->add_fixit_replace (open_paren_loc, pp_formatted_text (&pp));

  /* Replace the close paren with "> (".  */
  rich_loc->add_fixit_replace (close_paren_loc, "> (");

  /* Add a closing paren after the expr (the primary range of RICH_LOC).  */
  rich_loc->add_fixit_insert_after (")");
}


/* Parse a cast-expression.

   cast-expression:
     unary-expression
     ( type-id ) cast-expression

   ADDRESS_P is true iff the unary-expression is appearing as the
   operand of the `&' operator.   CAST_P is true if this expression is
   the target of a cast.

   Returns a representation of the expression.  */

static cp_expr
cp_parser_cast_expression (cp_parser *parser, bool address_p, bool cast_p,
			   bool decltype_p, cp_id_kind * pidk)
{
  /* If it's a `(', then we might be looking at a cast.  */
  if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_PAREN))
    {
      tree type = NULL_TREE;
      cp_expr expr (NULL_TREE);
      int cast_expression = 0;
      const char *saved_message;

      /* There's no way to know yet whether or not this is a cast.
	 For example, `(int (3))' is a unary-expression, while `(int)
	 3' is a cast.  So, we resort to parsing tentatively.  */
      cp_parser_parse_tentatively (parser);
      /* Types may not be defined in a cast.  */
      saved_message = parser->type_definition_forbidden_message;
      parser->type_definition_forbidden_message
	= G_("types may not be defined in casts");
      /* Consume the `('.  */
      matching_parens parens;
      cp_token *open_paren = parens.consume_open (parser);
      location_t open_paren_loc = open_paren->location;
      location_t close_paren_loc = UNKNOWN_LOCATION;

      /* A very tricky bit is that `(struct S) { 3 }' is a
	 compound-literal (which we permit in C++ as an extension).
	 But, that construct is not a cast-expression -- it is a
	 postfix-expression.  (The reason is that `(struct S) { 3 }.i'
	 is legal; if the compound-literal were a cast-expression,
	 you'd need an extra set of parentheses.)  But, if we parse
	 the type-id, and it happens to be a class-specifier, then we
	 will commit to the parse at that point, because we cannot
	 undo the action that is done when creating a new class.  So,
	 then we cannot back up and do a postfix-expression.

	 Another tricky case is the following (c++/29234):

         struct S { void operator () (); };

         void foo ()
         {
           ( S()() );
         }

	 As a type-id we parse the parenthesized S()() as a function
	 returning a function, groktypename complains and we cannot
	 back up in this case either.

	 Therefore, we scan ahead to the closing `)', and check to see
	 if the tokens after the `)' can start a cast-expression.  Otherwise
	 we are dealing with an unary-expression, a postfix-expression
	 or something else.

	 Yet another tricky case, in C++11, is the following (c++/54891):

	 (void)[]{};

         The issue is that usually, besides the case of lambda-expressions,
	 the parenthesized type-id cannot be followed by '[', and, eg, we
	 want to parse '(C ())[2];' in parse/pr26997.C as unary-expression.
	 Thus, if cp_parser_tokens_start_cast_expression returns -1, below
	 we don't commit, we try a cast-expression, then an unary-expression.

	 Save tokens so that we can put them back.  */
      cp_lexer_save_tokens (parser->lexer);

      /* We may be looking at a cast-expression.  */
      if (cp_parser_skip_to_closing_parenthesis (parser, false, false,
						 /*consume_paren=*/true))
	cast_expression
	  = cp_parser_tokens_start_cast_expression (parser);

      /* Roll back the tokens we skipped.  */
      cp_lexer_rollback_tokens (parser->lexer);
      /* If we aren't looking at a cast-expression, simulate an error so
	 that the call to cp_parser_error_occurred below returns true.  */
      if (!cast_expression)
	cp_parser_simulate_error (parser);
      else
	{
	  bool saved_in_type_id_in_expr_p = parser->in_type_id_in_expr_p;
	  parser->in_type_id_in_expr_p = true;
	  /* Look for the type-id.  */
	  type = cp_parser_type_id (parser);
	  /* Look for the closing `)'.  */
	  cp_token *close_paren = parens.require_close (parser);
	  if (close_paren)
	    close_paren_loc = close_paren->location;
	  parser->in_type_id_in_expr_p = saved_in_type_id_in_expr_p;
	}

      /* Restore the saved message.  */
      parser->type_definition_forbidden_message = saved_message;

      /* At this point this can only be either a cast or a
	 parenthesized ctor such as `(T ())' that looks like a cast to
	 function returning T.  */
      if (!cp_parser_error_occurred (parser))
	{
	  /* Only commit if the cast-expression doesn't start with
	     '++', '--', or '[' in C++11.  */
	  if (cast_expression > 0)
	    cp_parser_commit_to_topmost_tentative_parse (parser);

	  expr = cp_parser_cast_expression (parser,
					    /*address_p=*/false,
					    /*cast_p=*/true,
					    /*decltype_p=*/false,
					    pidk);

	  if (cp_parser_parse_definitely (parser))
	    {
	      /* Warn about old-style casts, if so requested.  */
	      if (warn_old_style_cast
		  && !in_system_header_at (input_location)
		  && !VOID_TYPE_P (type)
		  && current_lang_name != lang_name_c)
		{
		  gcc_rich_location rich_loc (input_location);
		  maybe_add_cast_fixit (&rich_loc, open_paren_loc, close_paren_loc,
					expr, type);
		  warning_at_rich_loc (&rich_loc, OPT_Wold_style_cast,
				       "use of old-style cast to %q#T", type);
		}

	      /* Only type conversions to integral or enumeration types
		 can be used in constant-expressions.  */
	      if (!cast_valid_in_integral_constant_expression_p (type)
		  && cp_parser_non_integral_constant_expression (parser,
								 NIC_CAST))
		return error_mark_node;

	      /* Perform the cast.  */
	      /* Make a location:
		   (TYPE) EXPR
		   ^~~~~~~~~~~
		 with start==caret at the open paren, extending to the
		 end of "expr".  */
	      location_t cast_loc = make_location (open_paren_loc,
						   open_paren_loc,
						   expr.get_finish ());
	      expr = build_c_cast (cast_loc, type, expr);
	      return expr;
	    }
	}
      else 
        cp_parser_abort_tentative_parse (parser);
    }

  /* If we get here, then it's not a cast, so it must be a
     unary-expression.  */
  return cp_parser_unary_expression (parser, pidk, address_p,
				     cast_p, decltype_p);
}

/* Parse a binary expression of the general form:

   pm-expression:
     cast-expression
     pm-expression .* cast-expression
     pm-expression ->* cast-expression

   multiplicative-expression:
     pm-expression
     multiplicative-expression * pm-expression
     multiplicative-expression / pm-expression
     multiplicative-expression % pm-expression

   additive-expression:
     multiplicative-expression
     additive-expression + multiplicative-expression
     additive-expression - multiplicative-expression

   shift-expression:
     additive-expression
     shift-expression << additive-expression
     shift-expression >> additive-expression

   relational-expression:
     shift-expression
     relational-expression < shift-expression
     relational-expression > shift-expression
     relational-expression <= shift-expression
     relational-expression >= shift-expression

  GNU Extension:

   relational-expression:
     relational-expression <? shift-expression
     relational-expression >? shift-expression

   equality-expression:
     relational-expression
     equality-expression == relational-expression
     equality-expression != relational-expression

   and-expression:
     equality-expression
     and-expression & equality-expression

   exclusive-or-expression:
     and-expression
     exclusive-or-expression ^ and-expression

   inclusive-or-expression:
     exclusive-or-expression
     inclusive-or-expression | exclusive-or-expression

   logical-and-expression:
     inclusive-or-expression
     logical-and-expression && inclusive-or-expression

   logical-or-expression:
     logical-and-expression
     logical-or-expression || logical-and-expression

   All these are implemented with a single function like:

   binary-expression:
     simple-cast-expression
     binary-expression <token> binary-expression

   CAST_P is true if this expression is the target of a cast.

   The binops_by_token map is used to get the tree codes for each <token> type.
   binary-expressions are associated according to a precedence table.  */

#define TOKEN_PRECEDENCE(token)				     \
(((token->type == CPP_GREATER				     \
   || ((cxx_dialect != cxx98) && token->type == CPP_RSHIFT)) \
  && !parser->greater_than_is_operator_p)		     \
 ? PREC_NOT_OPERATOR					     \
 : binops_by_token[token->type].prec)

static cp_expr
cp_parser_binary_expression (cp_parser* parser, bool cast_p,
			     bool no_toplevel_fold_p,
			     bool decltype_p,
			     enum cp_parser_prec prec,
			     cp_id_kind * pidk)
{
  cp_parser_expression_stack stack;
  cp_parser_expression_stack_entry *sp = &stack[0];
  cp_parser_expression_stack_entry current;
  cp_expr rhs;
  cp_token *token;
  enum tree_code rhs_type;
  enum cp_parser_prec new_prec, lookahead_prec;
  tree overload;

  /* Parse the first expression.  */
  current.lhs_type = (cp_lexer_next_token_is (parser->lexer, CPP_NOT)
		      ? TRUTH_NOT_EXPR : ERROR_MARK);
  current.lhs = cp_parser_cast_expression (parser, /*address_p=*/false,
					   cast_p, decltype_p, pidk);
  current.prec = prec;

  if (cp_parser_error_occurred (parser))
    return error_mark_node;

  for (;;)
    {
      /* Get an operator token.  */
      token = cp_lexer_peek_token (parser->lexer);

      if (warn_cxx11_compat
          && token->type == CPP_RSHIFT
          && !parser->greater_than_is_operator_p)
        {
          if (warning_at (token->location, OPT_Wc__11_compat,
			  "%<>>%> operator is treated"
			  " as two right angle brackets in C++11"))
	    inform (token->location,
		    "suggest parentheses around %<>>%> expression");
        }

      new_prec = TOKEN_PRECEDENCE (token);
      if (new_prec != PREC_NOT_OPERATOR
	  && cp_lexer_nth_token_is (parser->lexer, 2, CPP_ELLIPSIS))
	/* This is a fold-expression; handle it later.  */
	new_prec = PREC_NOT_OPERATOR;

      /* Popping an entry off the stack means we completed a subexpression:
	 - either we found a token which is not an operator (`>' where it is not
	   an operator, or prec == PREC_NOT_OPERATOR), in which case popping
	   will happen repeatedly;
	 - or, we found an operator which has lower priority.  This is the case
	   where the recursive descent *ascends*, as in `3 * 4 + 5' after
	   parsing `3 * 4'.  */
      if (new_prec <= current.prec)
	{
	  if (sp == stack)
	    break;
	  else
	    goto pop;
	}

     get_rhs:
      current.tree_type = binops_by_token[token->type].tree_type;
      current.loc = token->location;

      /* We used the operator token.  */
      cp_lexer_consume_token (parser->lexer);

      /* For "false && x" or "true || x", x will never be executed;
	 disable warnings while evaluating it.  */
      if (current.tree_type == TRUTH_ANDIF_EXPR)
	c_inhibit_evaluation_warnings +=
	  cp_fully_fold (current.lhs) == truthvalue_false_node;
      else if (current.tree_type == TRUTH_ORIF_EXPR)
	c_inhibit_evaluation_warnings +=
	  cp_fully_fold (current.lhs) == truthvalue_true_node;

      /* Extract another operand.  It may be the RHS of this expression
	 or the LHS of a new, higher priority expression.  */
      rhs_type = (cp_lexer_next_token_is (parser->lexer, CPP_NOT)
		  ? TRUTH_NOT_EXPR : ERROR_MARK);
      rhs = cp_parser_simple_cast_expression (parser);

      /* Get another operator token.  Look up its precedence to avoid
	 building a useless (immediately popped) stack entry for common
	 cases such as 3 + 4 + 5 or 3 * 4 + 5.  */
      token = cp_lexer_peek_token (parser->lexer);
      lookahead_prec = TOKEN_PRECEDENCE (token);
      if (lookahead_prec != PREC_NOT_OPERATOR
	  && cp_lexer_nth_token_is (parser->lexer, 2, CPP_ELLIPSIS))
	lookahead_prec = PREC_NOT_OPERATOR;
      if (lookahead_prec > new_prec)
	{
	  /* ... and prepare to parse the RHS of the new, higher priority
	     expression.  Since precedence levels on the stack are
	     monotonically increasing, we do not have to care about
	     stack overflows.  */
	  *sp = current;
	  ++sp;
	  current.lhs = rhs;
	  current.lhs_type = rhs_type;
	  current.prec = new_prec;
	  new_prec = lookahead_prec;
	  goto get_rhs;

	 pop:
	  lookahead_prec = new_prec;
	  /* If the stack is not empty, we have parsed into LHS the right side
	     (`4' in the example above) of an expression we had suspended.
	     We can use the information on the stack to recover the LHS (`3')
	     from the stack together with the tree code (`MULT_EXPR'), and
	     the precedence of the higher level subexpression
	     (`PREC_ADDITIVE_EXPRESSION').  TOKEN is the CPP_PLUS token,
	     which will be used to actually build the additive expression.  */
	  rhs = current.lhs;
	  rhs_type = current.lhs_type;
	  --sp;
	  current = *sp;
	}

      /* Undo the disabling of warnings done above.  */
      if (current.tree_type == TRUTH_ANDIF_EXPR)
	c_inhibit_evaluation_warnings -=
	  cp_fully_fold (current.lhs) == truthvalue_false_node;
      else if (current.tree_type == TRUTH_ORIF_EXPR)
	c_inhibit_evaluation_warnings -=
	  cp_fully_fold (current.lhs) == truthvalue_true_node;

      if (warn_logical_not_paren
	  && TREE_CODE_CLASS (current.tree_type) == tcc_comparison
	  && current.lhs_type == TRUTH_NOT_EXPR
	  /* Avoid warning for !!x == y.  */
	  && (TREE_CODE (current.lhs) != NE_EXPR
	      || !integer_zerop (TREE_OPERAND (current.lhs, 1)))
	  && (TREE_CODE (current.lhs) != TRUTH_NOT_EXPR
	      || (TREE_CODE (TREE_OPERAND (current.lhs, 0)) != TRUTH_NOT_EXPR
		  /* Avoid warning for !b == y where b is boolean.  */
		  && (TREE_TYPE (TREE_OPERAND (current.lhs, 0)) == NULL_TREE
		      || (TREE_CODE (TREE_TYPE (TREE_OPERAND (current.lhs, 0)))
			  != BOOLEAN_TYPE))))
	  /* Avoid warning for !!b == y where b is boolean.  */
	  && (!DECL_P (current.lhs)
	      || TREE_TYPE (current.lhs) == NULL_TREE
	      || TREE_CODE (TREE_TYPE (current.lhs)) != BOOLEAN_TYPE))
	warn_logical_not_parentheses (current.loc, current.tree_type,
				      current.lhs, maybe_constant_value (rhs));

      overload = NULL;

      location_t combined_loc = make_location (current.loc,
					       current.lhs.get_start (),
					       rhs.get_finish ());

      /* ??? Currently we pass lhs_type == ERROR_MARK and rhs_type ==
	 ERROR_MARK for everything that is not a binary expression.
	 This makes warn_about_parentheses miss some warnings that
	 involve unary operators.  For unary expressions we should
	 pass the correct tree_code unless the unary expression was
	 surrounded by parentheses.
      */
      if (no_toplevel_fold_p
	  && lookahead_prec <= current.prec
	  && sp == stack)
	current.lhs = build2_loc (combined_loc,
				  current.tree_type,
				  TREE_CODE_CLASS (current.tree_type)
				  == tcc_comparison
				  ? boolean_type_node : TREE_TYPE (current.lhs),
				  current.lhs, rhs);
      else
        {
          current.lhs = build_x_binary_op (combined_loc, current.tree_type,
                                           current.lhs, current.lhs_type,
                                           rhs, rhs_type, &overload,
                                           complain_flags (decltype_p));
          /* TODO: build_x_binary_op doesn't always honor the location.  */
          current.lhs.set_location (combined_loc);
        }
      current.lhs_type = current.tree_type;

      /* If the binary operator required the use of an overloaded operator,
	 then this expression cannot be an integral constant-expression.
	 An overloaded operator can be used even if both operands are
	 otherwise permissible in an integral constant-expression if at
	 least one of the operands is of enumeration type.  */

      if (overload
	  && cp_parser_non_integral_constant_expression (parser,
							 NIC_OVERLOADED))
	return error_mark_node;
    }

  return current.lhs;
}

static cp_expr
cp_parser_binary_expression (cp_parser* parser, bool cast_p,
			     bool no_toplevel_fold_p,
			     enum cp_parser_prec prec,
			     cp_id_kind * pidk)
{
  return cp_parser_binary_expression (parser, cast_p, no_toplevel_fold_p,
				      /*decltype*/false, prec, pidk);
}

/* Parse the `? expression : assignment-expression' part of a
   conditional-expression.  The LOGICAL_OR_EXPR is the
   logical-or-expression that started the conditional-expression.
   Returns a representation of the entire conditional-expression.

   This routine is used by cp_parser_assignment_expression.

     ? expression : assignment-expression

   GNU Extensions:

     ? : assignment-expression */

static tree
cp_parser_question_colon_clause (cp_parser* parser, cp_expr logical_or_expr)
{
  tree expr, folded_logical_or_expr = cp_fully_fold (logical_or_expr);
  cp_expr assignment_expr;
  struct cp_token *token;
  location_t loc = cp_lexer_peek_token (parser->lexer)->location;

  /* Consume the `?' token.  */
  cp_lexer_consume_token (parser->lexer);
  token = cp_lexer_peek_token (parser->lexer);
  if (cp_parser_allow_gnu_extensions_p (parser)
      && token->type == CPP_COLON)
    {
      pedwarn (token->location, OPT_Wpedantic, 
               "ISO C++ does not allow ?: with omitted middle operand");
      /* Implicit true clause.  */
      expr = NULL_TREE;
      c_inhibit_evaluation_warnings +=
	folded_logical_or_expr == truthvalue_true_node;
      warn_for_omitted_condop (token->location, logical_or_expr);
    }
  else
    {
      bool saved_colon_corrects_to_scope_p = parser->colon_corrects_to_scope_p;
      parser->colon_corrects_to_scope_p = false;
      /* Parse the expression.  */
      c_inhibit_evaluation_warnings +=
	folded_logical_or_expr == truthvalue_false_node;
      expr = cp_parser_expression (parser);
      c_inhibit_evaluation_warnings +=
	((folded_logical_or_expr == truthvalue_true_node)
	 - (folded_logical_or_expr == truthvalue_false_node));
      parser->colon_corrects_to_scope_p = saved_colon_corrects_to_scope_p;
    }

  /* The next token should be a `:'.  */
  cp_parser_require (parser, CPP_COLON, RT_COLON);
  /* Parse the assignment-expression.  */
  assignment_expr = cp_parser_assignment_expression (parser);
  c_inhibit_evaluation_warnings -=
    folded_logical_or_expr == truthvalue_true_node;

  /* Make a location:
       LOGICAL_OR_EXPR ? EXPR : ASSIGNMENT_EXPR
       ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
     with the caret at the "?", ranging from the start of
     the logical_or_expr to the end of the assignment_expr.  */
  loc = make_location (loc,
		       logical_or_expr.get_start (),
		       assignment_expr.get_finish ());

  /* Build the conditional-expression.  */
  return build_x_conditional_expr (loc, logical_or_expr,
				   expr,
				   assignment_expr,
                                   tf_warning_or_error);
}

/* Parse an assignment-expression.

   assignment-expression:
     conditional-expression
     logical-or-expression assignment-operator assignment_expression
     throw-expression

   CAST_P is true if this expression is the target of a cast.
   DECLTYPE_P is true if this expression is the operand of decltype.

   Returns a representation for the expression.  */

static cp_expr
cp_parser_assignment_expression (cp_parser* parser, cp_id_kind * pidk,
				 bool cast_p, bool decltype_p)
{
  cp_expr expr;

  /* If the next token is the `throw' keyword, then we're looking at
     a throw-expression.  */
  if (cp_lexer_next_token_is_keyword (parser->lexer, RID_THROW))
    expr = cp_parser_throw_expression (parser);
  /* Otherwise, it must be that we are looking at a
     logical-or-expression.  */
  else
    {
      /* Parse the binary expressions (logical-or-expression).  */
      expr = cp_parser_binary_expression (parser, cast_p, false,
					  decltype_p,
					  PREC_NOT_OPERATOR, pidk);
      /* If the next token is a `?' then we're actually looking at a
	 conditional-expression.  */
      if (cp_lexer_next_token_is (parser->lexer, CPP_QUERY))
	return cp_parser_question_colon_clause (parser, expr);
      else
	{
	  location_t loc = cp_lexer_peek_token (parser->lexer)->location;

	  /* If it's an assignment-operator, we're using the second
	     production.  */
	  enum tree_code assignment_operator
	    = cp_parser_assignment_operator_opt (parser);
	  if (assignment_operator != ERROR_MARK)
	    {
	      bool non_constant_p;

	      /* Parse the right-hand side of the assignment.  */
	      cp_expr rhs = cp_parser_initializer_clause (parser,
							  &non_constant_p);

	      if (BRACE_ENCLOSED_INITIALIZER_P (rhs))
		maybe_warn_cpp0x (CPP0X_INITIALIZER_LISTS);

	      /* An assignment may not appear in a
		 constant-expression.  */
	      if (cp_parser_non_integral_constant_expression (parser,
							      NIC_ASSIGNMENT))
		return error_mark_node;
	      /* Build the assignment expression.  Its default
		 location:
		   LHS = RHS
		   ~~~~^~~~~
		 is the location of the '=' token as the
		 caret, ranging from the start of the lhs to the
		 end of the rhs.  */
	      loc = make_location (loc,
				   expr.get_start (),
				   rhs.get_finish ());
	      expr = build_x_modify_expr (loc, expr,
					  assignment_operator,
					  rhs,
					  complain_flags (decltype_p));
              /* TODO: build_x_modify_expr doesn't honor the location,
                 so we must set it here.  */
              expr.set_location (loc);
	    }
	}
    }

  return expr;
}

/* Parse an (optional) assignment-operator.

   assignment-operator: one of
     = *= /= %= += -= >>= <<= &= ^= |=

   GNU Extension:

   assignment-operator: one of
     <?= >?=

   If the next token is an assignment operator, the corresponding tree
   code is returned, and the token is consumed.  For example, for
   `+=', PLUS_EXPR is returned.  For `=' itself, the code returned is
   NOP_EXPR.  For `/', TRUNC_DIV_EXPR is returned; for `%',
   TRUNC_MOD_EXPR is returned.  If TOKEN is not an assignment
   operator, ERROR_MARK is returned.  */

static enum tree_code
cp_parser_assignment_operator_opt (cp_parser* parser)
{
  enum tree_code op;
  cp_token *token;

  /* Peek at the next token.  */
  token = cp_lexer_peek_token (parser->lexer);

  switch (token->type)
    {
    case CPP_EQ:
      op = NOP_EXPR;
      break;

    case CPP_MULT_EQ:
      op = MULT_EXPR;
      break;

    case CPP_DIV_EQ:
      op = TRUNC_DIV_EXPR;
      break;

    case CPP_MOD_EQ:
      op = TRUNC_MOD_EXPR;
      break;

    case CPP_PLUS_EQ:
      op = PLUS_EXPR;
      break;

    case CPP_MINUS_EQ:
      op = MINUS_EXPR;
      break;

    case CPP_RSHIFT_EQ:
      op = RSHIFT_EXPR;
      break;

    case CPP_LSHIFT_EQ:
      op = LSHIFT_EXPR;
      break;

    case CPP_AND_EQ:
      op = BIT_AND_EXPR;
      break;

    case CPP_XOR_EQ:
      op = BIT_XOR_EXPR;
      break;

    case CPP_OR_EQ:
      op = BIT_IOR_EXPR;
      break;

    default:
      /* Nothing else is an assignment operator.  */
      op = ERROR_MARK;
    }

  /* An operator followed by ... is a fold-expression, handled elsewhere.  */
  if (op != ERROR_MARK
      && cp_lexer_nth_token_is (parser->lexer, 2, CPP_ELLIPSIS))
    op = ERROR_MARK;

  /* If it was an assignment operator, consume it.  */
  if (op != ERROR_MARK)
    cp_lexer_consume_token (parser->lexer);

  return op;
}

/* Parse an expression.

   expression:
     assignment-expression
     expression , assignment-expression

   CAST_P is true if this expression is the target of a cast.
   DECLTYPE_P is true if this expression is the immediate operand of decltype,
     except possibly parenthesized or on the RHS of a comma (N3276).

   Returns a representation of the expression.  */

static cp_expr
cp_parser_expression (cp_parser* parser, cp_id_kind * pidk,
		      bool cast_p, bool decltype_p)
{
  cp_expr expression = NULL_TREE;
  location_t loc = UNKNOWN_LOCATION;

  while (true)
    {
      cp_expr assignment_expression;

      /* Parse the next assignment-expression.  */
      assignment_expression
	= cp_parser_assignment_expression (parser, pidk, cast_p, decltype_p);

      /* We don't create a temporary for a call that is the immediate operand
	 of decltype or on the RHS of a comma.  But when we see a comma, we
	 need to create a temporary for a call on the LHS.  */
      if (decltype_p && !processing_template_decl
	  && TREE_CODE (assignment_expression) == CALL_EXPR
	  && CLASS_TYPE_P (TREE_TYPE (assignment_expression))
	  && cp_lexer_next_token_is (parser->lexer, CPP_COMMA))
	assignment_expression
	  = build_cplus_new (TREE_TYPE (assignment_expression),
			     assignment_expression, tf_warning_or_error);

      /* If this is the first assignment-expression, we can just
	 save it away.  */
      if (!expression)
	expression = assignment_expression;
      else
	{
	  /* Create a location with caret at the comma, ranging
	     from the start of the LHS to the end of the RHS.  */
	  loc = make_location (loc,
			       expression.get_start (),
			       assignment_expression.get_finish ());
	  expression = build_x_compound_expr (loc, expression,
					      assignment_expression,
					      complain_flags (decltype_p));
	  expression.set_location (loc);
	}
      /* If the next token is not a comma, or we're in a fold-expression, then
	 we are done with the expression.  */
      if (cp_lexer_next_token_is_not (parser->lexer, CPP_COMMA)
	  || cp_lexer_nth_token_is (parser->lexer, 2, CPP_ELLIPSIS))
	break;
      /* Consume the `,'.  */
      loc = cp_lexer_peek_token (parser->lexer)->location;
      cp_lexer_consume_token (parser->lexer);
      /* A comma operator cannot appear in a constant-expression.  */
      if (cp_parser_non_integral_constant_expression (parser, NIC_COMMA))
	expression = error_mark_node;
    }

  return expression;
}

/* Parse a constant-expression.

   constant-expression:
     conditional-expression

  If ALLOW_NON_CONSTANT_P a non-constant expression is silently
  accepted.  If ALLOW_NON_CONSTANT_P is true and the expression is not
  constant, *NON_CONSTANT_P is set to TRUE.  If ALLOW_NON_CONSTANT_P
  is false, NON_CONSTANT_P should be NULL.  If STRICT_P is true,
  only parse a conditional-expression, otherwise parse an
  assignment-expression.  See below for rationale.  */

static cp_expr
cp_parser_constant_expression (cp_parser* parser,
			       bool allow_non_constant_p,
			       bool *non_constant_p,
			       bool strict_p)
{
  bool saved_integral_constant_expression_p;
  bool saved_allow_non_integral_constant_expression_p;
  bool saved_non_integral_constant_expression_p;
  cp_expr expression;

  /* It might seem that we could simply parse the
     conditional-expression, and then check to see if it were
     TREE_CONSTANT.  However, an expression that is TREE_CONSTANT is
     one that the compiler can figure out is constant, possibly after
     doing some simplifications or optimizations.  The standard has a
     precise definition of constant-expression, and we must honor
     that, even though it is somewhat more restrictive.

     For example:

       int i[(2, 3)];

     is not a legal declaration, because `(2, 3)' is not a
     constant-expression.  The `,' operator is forbidden in a
     constant-expression.  However, GCC's constant-folding machinery
     will fold this operation to an INTEGER_CST for `3'.  */

  /* Save the old settings.  */
  saved_integral_constant_expression_p = parser->integral_constant_expression_p;
  saved_allow_non_integral_constant_expression_p
    = parser->allow_non_integral_constant_expression_p;
  saved_non_integral_constant_expression_p = parser->non_integral_constant_expression_p;
  /* We are now parsing a constant-expression.  */
  parser->integral_constant_expression_p = true;
  parser->allow_non_integral_constant_expression_p
    = (allow_non_constant_p || cxx_dialect >= cxx11);
  parser->non_integral_constant_expression_p = false;
  /* Although the grammar says "conditional-expression", when not STRICT_P,
     we parse an "assignment-expression", which also permits
     "throw-expression" and the use of assignment operators.  In the case
     that ALLOW_NON_CONSTANT_P is false, we get better errors than we would
     otherwise.  In the case that ALLOW_NON_CONSTANT_P is true, it is
     actually essential that we look for an assignment-expression.
     For example, cp_parser_initializer_clauses uses this function to
     determine whether a particular assignment-expression is in fact
     constant.  */
  if (strict_p)
    {
      /* Parse the binary expressions (logical-or-expression).  */
      expression = cp_parser_binary_expression (parser, false, false, false,
						PREC_NOT_OPERATOR, NULL);
      /* If the next token is a `?' then we're actually looking at
	 a conditional-expression; otherwise we're done.  */
      if (cp_lexer_next_token_is (parser->lexer, CPP_QUERY))
	expression = cp_parser_question_colon_clause (parser, expression);
    }
  else
    expression = cp_parser_assignment_expression (parser);
  /* Restore the old settings.  */
  parser->integral_constant_expression_p
    = saved_integral_constant_expression_p;
  parser->allow_non_integral_constant_expression_p
    = saved_allow_non_integral_constant_expression_p;
  if (cxx_dialect >= cxx11)
    {
      /* Require an rvalue constant expression here; that's what our
	 callers expect.  Reference constant expressions are handled
	 separately in e.g. cp_parser_template_argument.  */
      tree decay = expression;
      if (TREE_TYPE (expression)
	  && TREE_CODE (TREE_TYPE (expression)) == ARRAY_TYPE)
	decay = build_address (expression);
      bool is_const = potential_rvalue_constant_expression (decay);
      parser->non_integral_constant_expression_p = !is_const;
      if (!is_const && !allow_non_constant_p)
	require_potential_rvalue_constant_expression (decay);
    }
  if (allow_non_constant_p)
    *non_constant_p = parser->non_integral_constant_expression_p;
  parser->non_integral_constant_expression_p
    = saved_non_integral_constant_expression_p;

  return expression;
}

/* Parse __builtin_offsetof.

   offsetof-expression:
     "__builtin_offsetof" "(" type-id "," offsetof-member-designator ")"

   offsetof-member-designator:
     id-expression
     | offsetof-member-designator "." id-expression
     | offsetof-member-designator "[" expression "]"
     | offsetof-member-designator "->" id-expression  */

static cp_expr
cp_parser_builtin_offsetof (cp_parser *parser)
{
  int save_ice_p, save_non_ice_p;
  tree type;
  cp_expr expr;
  cp_id_kind dummy;
  cp_token *token;
  location_t finish_loc;

  /* We're about to accept non-integral-constant things, but will
     definitely yield an integral constant expression.  Save and
     restore these values around our local parsing.  */
  save_ice_p = parser->integral_constant_expression_p;
  save_non_ice_p = parser->non_integral_constant_expression_p;

  location_t start_loc = cp_lexer_peek_token (parser->lexer)->location;

  /* Consume the "__builtin_offsetof" token.  */
  cp_lexer_consume_token (parser->lexer);
  /* Consume the opening `('.  */
  matching_parens parens;
  parens.require_open (parser);
  /* Parse the type-id.  */
  location_t loc = cp_lexer_peek_token (parser->lexer)->location;
  type = cp_parser_type_id (parser);
  /* Look for the `,'.  */
  cp_parser_require (parser, CPP_COMMA, RT_COMMA);
  token = cp_lexer_peek_token (parser->lexer);

  /* Build the (type *)null that begins the traditional offsetof macro.  */
  tree object_ptr
    = build_static_cast (build_pointer_type (type), null_pointer_node,
			 tf_warning_or_error);

  /* Parse the offsetof-member-designator.  We begin as if we saw "expr->".  */
  expr = cp_parser_postfix_dot_deref_expression (parser, CPP_DEREF, object_ptr,
						 true, &dummy, token->location);
  while (true)
    {
      token = cp_lexer_peek_token (parser->lexer);
      switch (token->type)
	{
	case CPP_OPEN_SQUARE:
	  /* offsetof-member-designator "[" expression "]" */
	  expr = cp_parser_postfix_open_square_expression (parser, expr,
							   true, false);
	  break;

	case CPP_DEREF:
	  /* offsetof-member-designator "->" identifier */
	  expr = grok_array_decl (token->location, expr,
				  integer_zero_node, false);
	  /* FALLTHRU */

	case CPP_DOT:
	  /* offsetof-member-designator "." identifier */
	  cp_lexer_consume_token (parser->lexer);
	  expr = cp_parser_postfix_dot_deref_expression (parser, CPP_DOT,
							 expr, true, &dummy,
							 token->location);
	  break;

	case CPP_CLOSE_PAREN:
	  /* Consume the ")" token.  */
	  finish_loc = cp_lexer_peek_token (parser->lexer)->location;
	  cp_lexer_consume_token (parser->lexer);
	  goto success;

	default:
	  /* Error.  We know the following require will fail, but
	     that gives the proper error message.  */
	  parens.require_close (parser);
	  cp_parser_skip_to_closing_parenthesis (parser, true, false, true);
	  expr = error_mark_node;
	  goto failure;
	}
    }

 success:
  /* Make a location of the form:
       __builtin_offsetof (struct s, f)
       ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~
     with caret at the type-id, ranging from the start of the
     "_builtin_offsetof" token to the close paren.  */
  loc = make_location (loc, start_loc, finish_loc);
  /* The result will be an INTEGER_CST, so we need to explicitly
     preserve the location.  */
  expr = cp_expr (finish_offsetof (object_ptr, expr, loc), loc);

 failure:
  parser->integral_constant_expression_p = save_ice_p;
  parser->non_integral_constant_expression_p = save_non_ice_p;

  return expr;
}

/* Parse a trait expression.

   Returns a representation of the expression, the underlying type
   of the type at issue when KEYWORD is RID_UNDERLYING_TYPE.  */

static tree
cp_parser_trait_expr (cp_parser* parser, enum rid keyword)
{
  cp_trait_kind kind;
  tree type1, type2 = NULL_TREE;
  bool binary = false;
  bool variadic = false;

  switch (keyword)
    {
    case RID_HAS_NOTHROW_ASSIGN:
      kind = CPTK_HAS_NOTHROW_ASSIGN;
      break;
    case RID_HAS_NOTHROW_CONSTRUCTOR:
      kind = CPTK_HAS_NOTHROW_CONSTRUCTOR;
      break;
    case RID_HAS_NOTHROW_COPY:
      kind = CPTK_HAS_NOTHROW_COPY;
      break;
    case RID_HAS_TRIVIAL_ASSIGN:
      kind = CPTK_HAS_TRIVIAL_ASSIGN;
      break;
    case RID_HAS_TRIVIAL_CONSTRUCTOR:
      kind = CPTK_HAS_TRIVIAL_CONSTRUCTOR;
      break;
    case RID_HAS_TRIVIAL_COPY:
      kind = CPTK_HAS_TRIVIAL_COPY;
      break;
    case RID_HAS_TRIVIAL_DESTRUCTOR:
      kind = CPTK_HAS_TRIVIAL_DESTRUCTOR;
      break;
    case RID_HAS_UNIQUE_OBJ_REPRESENTATIONS:
      kind = CPTK_HAS_UNIQUE_OBJ_REPRESENTATIONS;
      break;
    case RID_HAS_VIRTUAL_DESTRUCTOR:
      kind = CPTK_HAS_VIRTUAL_DESTRUCTOR;
      break;
    case RID_IS_ABSTRACT:
      kind = CPTK_IS_ABSTRACT;
      break;
    case RID_IS_AGGREGATE:
      kind = CPTK_IS_AGGREGATE;
      break;
    case RID_IS_BASE_OF:
      kind = CPTK_IS_BASE_OF;
      binary = true;
      break;
    case RID_IS_CLASS:
      kind = CPTK_IS_CLASS;
      break;
    case RID_IS_EMPTY:
      kind = CPTK_IS_EMPTY;
      break;
    case RID_IS_ENUM:
      kind = CPTK_IS_ENUM;
      break;
    case RID_IS_FINAL:
      kind = CPTK_IS_FINAL;
      break;
    case RID_IS_LITERAL_TYPE:
      kind = CPTK_IS_LITERAL_TYPE;
      break;
    case RID_IS_POD:
      kind = CPTK_IS_POD;
      break;
    case RID_IS_POLYMORPHIC:
      kind = CPTK_IS_POLYMORPHIC;
      break;
    case RID_IS_SAME_AS:
      kind = CPTK_IS_SAME_AS;
      binary = true;
      break;
    case RID_IS_STD_LAYOUT:
      kind = CPTK_IS_STD_LAYOUT;
      break;
    case RID_IS_TRIVIAL:
      kind = CPTK_IS_TRIVIAL;
      break;
    case RID_IS_TRIVIALLY_ASSIGNABLE:
      kind = CPTK_IS_TRIVIALLY_ASSIGNABLE;
      binary = true;
      break;
    case RID_IS_TRIVIALLY_CONSTRUCTIBLE:
      kind = CPTK_IS_TRIVIALLY_CONSTRUCTIBLE;
      variadic = true;
      break;
    case RID_IS_TRIVIALLY_COPYABLE:
      kind = CPTK_IS_TRIVIALLY_COPYABLE;
      break;
    case RID_IS_UNION:
      kind = CPTK_IS_UNION;
      break;
    case RID_UNDERLYING_TYPE:
      kind = CPTK_UNDERLYING_TYPE;
      break;
    case RID_BASES:
      kind = CPTK_BASES;
      break;
    case RID_DIRECT_BASES:
      kind = CPTK_DIRECT_BASES;
      break;
    case RID_IS_ASSIGNABLE:
      kind = CPTK_IS_ASSIGNABLE;
      binary = true;
      break;
    case RID_IS_CONSTRUCTIBLE:
      kind = CPTK_IS_CONSTRUCTIBLE;
      variadic = true;
      break;
    default:
      gcc_unreachable ();
    }

  /* Consume the token.  */
  cp_lexer_consume_token (parser->lexer);

  matching_parens parens;
  parens.require_open (parser);

  {
    type_id_in_expr_sentinel s (parser);
    type1 = cp_parser_type_id (parser);
  }

  if (type1 == error_mark_node)
    return error_mark_node;

  if (binary)
    {
      cp_parser_require (parser, CPP_COMMA, RT_COMMA);
 
      {
	type_id_in_expr_sentinel s (parser);
	type2 = cp_parser_type_id (parser);
      }

      if (type2 == error_mark_node)
	return error_mark_node;
    }
  else if (variadic)
    {
      while (cp_lexer_next_token_is (parser->lexer, CPP_COMMA))
	{
	  cp_lexer_consume_token (parser->lexer);
	  tree elt = cp_parser_type_id (parser);
	  if (cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS))
	    {
	      cp_lexer_consume_token (parser->lexer);
	      elt = make_pack_expansion (elt);
	    }
	  if (elt == error_mark_node)
	    return error_mark_node;
	  type2 = tree_cons (NULL_TREE, elt, type2);
	}
    }

  parens.require_close (parser);

  /* Complete the trait expression, which may mean either processing
     the trait expr now or saving it for template instantiation.  */
  switch (kind)
    {
    case CPTK_UNDERLYING_TYPE:
      return finish_underlying_type (type1);
    case CPTK_BASES:
      return finish_bases (type1, false);
    case CPTK_DIRECT_BASES:
      return finish_bases (type1, true);
    default:
      return finish_trait_expr (kind, type1, type2);
    }
}

/* Parse a lambda expression.

   lambda-expression:
     lambda-introducer lambda-declarator [opt] compound-statement

   Returns a representation of the expression.  */

static cp_expr
cp_parser_lambda_expression (cp_parser* parser)
{
  tree lambda_expr = build_lambda_expr ();
  tree type;
  bool ok = true;
  cp_token *token = cp_lexer_peek_token (parser->lexer);
  cp_token_position start = 0;

  LAMBDA_EXPR_LOCATION (lambda_expr) = token->location;

  if (cp_unevaluated_operand)
    {
      if (!token->error_reported)
	{
	  error_at (LAMBDA_EXPR_LOCATION (lambda_expr),
		    "lambda-expression in unevaluated context");
	  token->error_reported = true;
	}
      ok = false;
    }
  else if (parser->in_template_argument_list_p)
    {
      if (!token->error_reported)
	{
	  error_at (token->location, "lambda-expression in template-argument");
	  token->error_reported = true;
	}
      ok = false;
    }

  /* We may be in the middle of deferred access check.  Disable
     it now.  */
  push_deferring_access_checks (dk_no_deferred);

  cp_parser_lambda_introducer (parser, lambda_expr);

  type = begin_lambda_type (lambda_expr);
  if (type == error_mark_node)
    return error_mark_node;

  record_lambda_scope (lambda_expr);

  /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set.  */
  determine_visibility (TYPE_NAME (type));

  /* Now that we've started the type, add the capture fields for any
     explicit captures.  */
  register_capture_members (LAMBDA_EXPR_CAPTURE_LIST (lambda_expr));

  {
    /* Inside the class, surrounding template-parameter-lists do not apply.  */
    unsigned int saved_num_template_parameter_lists
        = parser->num_template_parameter_lists;
    unsigned char in_statement = parser->in_statement;
    bool in_switch_statement_p = parser->in_switch_statement_p;
    bool fully_implicit_function_template_p
        = parser->fully_implicit_function_template_p;
    tree implicit_template_parms = parser->implicit_template_parms;
    cp_binding_level* implicit_template_scope = parser->implicit_template_scope;
    bool auto_is_implicit_function_template_parm_p
        = parser->auto_is_implicit_function_template_parm_p;

    parser->num_template_parameter_lists = 0;
    parser->in_statement = 0;
    parser->in_switch_statement_p = false;
    parser->fully_implicit_function_template_p = false;
    parser->implicit_template_parms = 0;
    parser->implicit_template_scope = 0;
    parser->auto_is_implicit_function_template_parm_p = false;

    /* By virtue of defining a local class, a lambda expression has access to
       the private variables of enclosing classes.  */

    ok &= cp_parser_lambda_declarator_opt (parser, lambda_expr);

    if (ok && cp_parser_error_occurred (parser))
      ok = false;

    if (ok)
      {
	if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_BRACE)
	    && cp_parser_start_tentative_firewall (parser))
	  start = token;
	cp_parser_lambda_body (parser, lambda_expr);
      }
    else if (cp_parser_require (parser, CPP_OPEN_BRACE, RT_OPEN_BRACE))
      {
	if (cp_parser_skip_to_closing_brace (parser))
	  cp_lexer_consume_token (parser->lexer);
      }

    /* The capture list was built up in reverse order; fix that now.  */
    LAMBDA_EXPR_CAPTURE_LIST (lambda_expr)
      = nreverse (LAMBDA_EXPR_CAPTURE_LIST (lambda_expr));

    if (ok)
      maybe_add_lambda_conv_op (type);

    type = finish_struct (type, /*attributes=*/NULL_TREE);

    parser->num_template_parameter_lists = saved_num_template_parameter_lists;
    parser->in_statement = in_statement;
    parser->in_switch_statement_p = in_switch_statement_p;
    parser->fully_implicit_function_template_p
	= fully_implicit_function_template_p;
    parser->implicit_template_parms = implicit_template_parms;
    parser->implicit_template_scope = implicit_template_scope;
    parser->auto_is_implicit_function_template_parm_p
	= auto_is_implicit_function_template_parm_p;
  }

  /* This field is only used during parsing of the lambda.  */
  LAMBDA_EXPR_THIS_CAPTURE (lambda_expr) = NULL_TREE;

  /* This lambda shouldn't have any proxies left at this point.  */
  gcc_assert (LAMBDA_EXPR_PENDING_PROXIES (lambda_expr) == NULL);
  /* And now that we're done, push proxies for an enclosing lambda.  */
  insert_pending_capture_proxies ();

  if (ok)
    lambda_expr = build_lambda_object (lambda_expr);
  else
    lambda_expr = error_mark_node;

  cp_parser_end_tentative_firewall (parser, start, lambda_expr);

  pop_deferring_access_checks ();

  return lambda_expr;
}

/* Parse the beginning of a lambda expression.

   lambda-introducer:
     [ lambda-capture [opt] ]

   LAMBDA_EXPR is the current representation of the lambda expression.  */

static void
cp_parser_lambda_introducer (cp_parser* parser, tree lambda_expr)
{
  /* Need commas after the first capture.  */
  bool first = true;

  /* Eat the leading `['.  */
  cp_parser_require (parser, CPP_OPEN_SQUARE, RT_OPEN_SQUARE);

  /* Record default capture mode.  "[&" "[=" "[&," "[=,"  */
  if (cp_lexer_next_token_is (parser->lexer, CPP_AND)
      && cp_lexer_peek_nth_token (parser->lexer, 2)->type != CPP_NAME)
    LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda_expr) = CPLD_REFERENCE;
  else if (cp_lexer_next_token_is (parser->lexer, CPP_EQ))
    LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda_expr) = CPLD_COPY;

  if (LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda_expr) != CPLD_NONE)
    {
      cp_lexer_consume_token (parser->lexer);
      first = false;
    }

  while (cp_lexer_next_token_is_not (parser->lexer, CPP_CLOSE_SQUARE))
    {
      cp_token* capture_token;
      tree capture_id;
      tree capture_init_expr;
      cp_id_kind idk = CP_ID_KIND_NONE;
      bool explicit_init_p = false;

      enum capture_kind_type
      {
	BY_COPY,
	BY_REFERENCE
      };
      enum capture_kind_type capture_kind = BY_COPY;

      if (cp_lexer_next_token_is (parser->lexer, CPP_EOF))
	{
	  error ("expected end of capture-list");
	  return;
	}

      if (first)
	first = false;
      else
	cp_parser_require (parser, CPP_COMMA, RT_COMMA);

      /* Possibly capture `this'.  */
      if (cp_lexer_next_token_is_keyword (parser->lexer, RID_THIS))
	{
	  location_t loc = cp_lexer_peek_token (parser->lexer)->location;
	  if (cxx_dialect < cxx2a
	      && LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda_expr) == CPLD_COPY)
	    pedwarn (loc, 0, "explicit by-copy capture of %<this%> redundant "
		     "with by-copy capture default");
	  cp_lexer_consume_token (parser->lexer);
	  add_capture (lambda_expr,
		       /*id=*/this_identifier,
		       /*initializer=*/finish_this_expr (),
		       /*by_reference_p=*/true,
		       explicit_init_p);
	  continue;
	}

      /* Possibly capture `*this'.  */
      if (cp_lexer_next_token_is (parser->lexer, CPP_MULT)
	  && cp_lexer_nth_token_is_keyword (parser->lexer, 2, RID_THIS))
	{
	  location_t loc = cp_lexer_peek_token (parser->lexer)->location;
	  if (cxx_dialect < cxx17)
	    pedwarn (loc, 0, "%<*this%> capture only available with "
			     "-std=c++17 or -std=gnu++17");
	  cp_lexer_consume_token (parser->lexer);
	  cp_lexer_consume_token (parser->lexer);
	  add_capture (lambda_expr,
		       /*id=*/this_identifier,
		       /*initializer=*/finish_this_expr (),
		       /*by_reference_p=*/false,
		       explicit_init_p);
	  continue;
	}

      /* Remember whether we want to capture as a reference or not.  */
      if (cp_lexer_next_token_is (parser->lexer, CPP_AND))
	{
	  capture_kind = BY_REFERENCE;
	  cp_lexer_consume_token (parser->lexer);
	}

      /* Get the identifier.  */
      capture_token = cp_lexer_peek_token (parser->lexer);
      capture_id = cp_parser_identifier (parser);

      if (capture_id == error_mark_node)
	/* Would be nice to have a cp_parser_skip_to_closing_x for general
           delimiters, but I modified this to stop on unnested ']' as well.  It
           was already changed to stop on unnested '}', so the
           "closing_parenthesis" name is no more misleading with my change.  */
	{
	  cp_parser_skip_to_closing_parenthesis (parser,
						 /*recovering=*/true,
						 /*or_comma=*/true,
						 /*consume_paren=*/true);
	  break;
	}

      /* Find the initializer for this capture.  */
      if (cp_lexer_next_token_is (parser->lexer, CPP_EQ)
	  || cp_lexer_next_token_is (parser->lexer, CPP_OPEN_PAREN)
	  || cp_lexer_next_token_is (parser->lexer, CPP_OPEN_BRACE))
	{
	  bool direct, non_constant;
	  /* An explicit initializer exists.  */
	  if (cxx_dialect < cxx14)
	    pedwarn (input_location, 0,
		     "lambda capture initializers "
		     "only available with -std=c++14 or -std=gnu++14");
	  capture_init_expr = cp_parser_initializer (parser, &direct,
						     &non_constant);
	  explicit_init_p = true;
	  if (capture_init_expr == NULL_TREE)
	    {
	      error ("empty initializer for lambda init-capture");
	      capture_init_expr = error_mark_node;
	    }
	}
      else
	{
	  const char* error_msg;

	  /* Turn the identifier into an id-expression.  */
	  capture_init_expr
	    = cp_parser_lookup_name_simple (parser, capture_id,
					    capture_token->location);

	  if (capture_init_expr == error_mark_node)
	    {
	      unqualified_name_lookup_error (capture_id);
	      continue;
	    }
	  else if (DECL_P (capture_init_expr)
		   && (!VAR_P (capture_init_expr)
		       && TREE_CODE (capture_init_expr) != PARM_DECL))
	    {
	      error_at (capture_token->location,
			"capture of non-variable %qD ",
			capture_init_expr);
	      inform (DECL_SOURCE_LOCATION (capture_init_expr),
		      "%q#D declared here", capture_init_expr);
	      continue;
	    }
	  if (VAR_P (capture_init_expr)
	      && decl_storage_duration (capture_init_expr) != dk_auto)
	    {
	      if (pedwarn (capture_token->location, 0, "capture of variable "
			   "%qD with non-automatic storage duration",
			   capture_init_expr))
		inform (DECL_SOURCE_LOCATION (capture_init_expr),
			"%q#D declared here", capture_init_expr);
	      continue;
	    }

	  capture_init_expr
            = finish_id_expression
                (capture_id,
		 capture_init_expr,
                 parser->scope,
                 &idk,
                 /*integral_constant_expression_p=*/false,
                 /*allow_non_integral_constant_expression_p=*/false,
                 /*non_integral_constant_expression_p=*/NULL,
                 /*template_p=*/false,
                 /*done=*/true,
                 /*address_p=*/false,
                 /*template_arg_p=*/false,
                 &error_msg,
                 capture_token->location);

	  if (cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS))
	    {
	      cp_lexer_consume_token (parser->lexer);
	      capture_init_expr = make_pack_expansion (capture_init_expr);
	    }
	  else
	    check_for_bare_parameter_packs (capture_init_expr);
	}

      if (LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda_expr) != CPLD_NONE
	  && !explicit_init_p)
	{
	  if (LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda_expr) == CPLD_COPY
	      && capture_kind == BY_COPY)
	    pedwarn (capture_token->location, 0, "explicit by-copy capture "
		     "of %qD redundant with by-copy capture default",
		     capture_id);
	  if (LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda_expr) == CPLD_REFERENCE
	      && capture_kind == BY_REFERENCE)
	    pedwarn (capture_token->location, 0, "explicit by-reference "
		     "capture of %qD redundant with by-reference capture "
		     "default", capture_id);
	}

      add_capture (lambda_expr,
		   capture_id,
		   capture_init_expr,
		   /*by_reference_p=*/capture_kind == BY_REFERENCE,
		   explicit_init_p);
    }

  cp_parser_require (parser, CPP_CLOSE_SQUARE, RT_CLOSE_SQUARE);
}

/* Parse the (optional) middle of a lambda expression.

   lambda-declarator:
     < template-parameter-list [opt] >
     ( parameter-declaration-clause [opt] )
       attribute-specifier [opt]
       decl-specifier-seq [opt]
       exception-specification [opt]
       lambda-return-type-clause [opt]

   LAMBDA_EXPR is the current representation of the lambda expression.  */

static bool
cp_parser_lambda_declarator_opt (cp_parser* parser, tree lambda_expr)
{
  /* 5.1.1.4 of the standard says:
       If a lambda-expression does not include a lambda-declarator, it is as if
       the lambda-declarator were ().
     This means an empty parameter list, no attributes, and no exception
     specification.  */
  tree param_list = void_list_node;
  tree attributes = NULL_TREE;
  tree exception_spec = NULL_TREE;
  tree template_param_list = NULL_TREE;
  tree tx_qual = NULL_TREE;
  tree return_type = NULL_TREE;
  cp_decl_specifier_seq lambda_specs;
  clear_decl_specs (&lambda_specs);

  /* The template-parameter-list is optional, but must begin with
     an opening angle if present.  */
  if (cp_lexer_next_token_is (parser->lexer, CPP_LESS))
    {
      if (cxx_dialect < cxx14)
	pedwarn (parser->lexer->next_token->location, 0,
		 "lambda templates are only available with "
		 "-std=c++14 or -std=gnu++14");
      else
	pedwarn (parser->lexer->next_token->location, OPT_Wpedantic,
		 "ISO C++ does not support lambda templates");

      cp_lexer_consume_token (parser->lexer);

      template_param_list = cp_parser_template_parameter_list (parser);

      cp_parser_skip_to_end_of_template_parameter_list (parser);

      /* We just processed one more parameter list.  */
      ++parser->num_template_parameter_lists;
    }

  /* The parameter-declaration-clause is optional (unless
     template-parameter-list was given), but must begin with an
     opening parenthesis if present.  */
  if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_PAREN))
    {
      matching_parens parens;
      parens.consume_open (parser);

      begin_scope (sk_function_parms, /*entity=*/NULL_TREE);

      /* Parse parameters.  */
      param_list = cp_parser_parameter_declaration_clause (parser);

      /* Default arguments shall not be specified in the
	 parameter-declaration-clause of a lambda-declarator.  */
      if (cxx_dialect < cxx14)
	for (tree t = param_list; t; t = TREE_CHAIN (t))
	  if (TREE_PURPOSE (t) && DECL_P (TREE_VALUE (t)))
	    pedwarn (DECL_SOURCE_LOCATION (TREE_VALUE (t)), OPT_Wpedantic,
		     "default argument specified for lambda parameter");

      parens.require_close (parser);

      attributes = cp_parser_attributes_opt (parser);

      /* In the decl-specifier-seq of the lambda-declarator, each
	 decl-specifier shall either be mutable or constexpr.  */
      int declares_class_or_enum;
      if (cp_lexer_next_token_is_decl_specifier_keyword (parser->lexer))
	cp_parser_decl_specifier_seq (parser,
				      CP_PARSER_FLAGS_ONLY_MUTABLE_OR_CONSTEXPR,
				      &lambda_specs, &declares_class_or_enum);
      if (lambda_specs.storage_class == sc_mutable)
	{
	  LAMBDA_EXPR_MUTABLE_P (lambda_expr) = 1;
	  if (lambda_specs.conflicting_specifiers_p)
	    error_at (lambda_specs.locations[ds_storage_class],
		      "duplicate %<mutable%>");
	}

      tx_qual = cp_parser_tx_qualifier_opt (parser);

      /* Parse optional exception specification.  */
      exception_spec = cp_parser_exception_specification_opt (parser);

      /* Parse optional trailing return type.  */
      if (cp_lexer_next_token_is (parser->lexer, CPP_DEREF))
        {
          cp_lexer_consume_token (parser->lexer);
          return_type = cp_parser_trailing_type_id (parser);
        }

      /* The function parameters must be in scope all the way until after the
         trailing-return-type in case of decltype.  */
      pop_bindings_and_leave_scope ();
    }
  else if (template_param_list != NULL_TREE) // generate diagnostic
    cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);

  /* Create the function call operator.

     Messing with declarators like this is no uglier than building up the
     FUNCTION_DECL by hand, and this is less likely to get out of sync with
     other code.  */
  {
    cp_decl_specifier_seq return_type_specs;
    cp_declarator* declarator;
    tree fco;
    int quals;
    void *p;

    clear_decl_specs (&return_type_specs);
    if (return_type)
      return_type_specs.type = return_type;
    else
      /* Maybe we will deduce the return type later.  */
      return_type_specs.type = make_auto ();

    if (lambda_specs.locations[ds_constexpr])
      {
	if (cxx_dialect >= cxx17)
	  return_type_specs.locations[ds_constexpr]
	    = lambda_specs.locations[ds_constexpr];
	else
	  error_at (lambda_specs.locations[ds_constexpr], "%<constexpr%> "
		    "lambda only available with -std=c++17 or -std=gnu++17");
      }

    p = obstack_alloc (&declarator_obstack, 0);

    declarator = make_id_declarator (NULL_TREE, cp_operator_id (CALL_EXPR),
				     sfk_none);

    quals = (LAMBDA_EXPR_MUTABLE_P (lambda_expr)
	     ? TYPE_UNQUALIFIED : TYPE_QUAL_CONST);
    declarator = make_call_declarator (declarator, param_list, quals,
				       VIRT_SPEC_UNSPECIFIED,
                                       REF_QUAL_NONE,
				       tx_qual,
				       exception_spec,
                                       /*late_return_type=*/NULL_TREE,
                                       /*requires_clause*/NULL_TREE);
    declarator->id_loc = LAMBDA_EXPR_LOCATION (lambda_expr);

    fco = grokmethod (&return_type_specs,
		      declarator,
		      attributes);
    if (fco != error_mark_node)
      {
	DECL_INITIALIZED_IN_CLASS_P (fco) = 1;
	DECL_ARTIFICIAL (fco) = 1;
	/* Give the object parameter a different name.  */
	DECL_NAME (DECL_ARGUMENTS (fco)) = get_identifier ("__closure");
	if (return_type)
	  TYPE_HAS_LATE_RETURN_TYPE (TREE_TYPE (fco)) = 1;
      }
    if (template_param_list)
      {
	fco = finish_member_template_decl (fco);
	finish_template_decl (template_param_list);
	--parser->num_template_parameter_lists;
      }
    else if (parser->fully_implicit_function_template_p)
      fco = finish_fully_implicit_template (parser, fco);

    finish_member_declaration (fco);

    obstack_free (&declarator_obstack, p);

    return (fco != error_mark_node);
  }
}

/* Parse the body of a lambda expression, which is simply

   compound-statement

   but which requires special handling.
   LAMBDA_EXPR is the current representation of the lambda expression.  */

static void
cp_parser_lambda_body (cp_parser* parser, tree lambda_expr)
{
  bool nested = (current_function_decl != NULL_TREE);
  bool local_variables_forbidden_p = parser->local_variables_forbidden_p;
  bool in_function_body = parser->in_function_body;
  if (nested)
    push_function_context ();
  else
    /* Still increment function_depth so that we don't GC in the
       middle of an expression.  */
    ++function_depth;
  vec<tree> omp_privatization_save;
  save_omp_privatization_clauses (omp_privatization_save);
  /* Clear this in case we're in the middle of a default argument.  */
  parser->local_variables_forbidden_p = false;
  parser->in_function_body = true;

  /* Finish the function call operator
     - class_specifier
     + late_parsing_for_member
     + function_definition_after_declarator
     + ctor_initializer_opt_and_function_body  */
  {
    local_specialization_stack s (lss_copy);

    tree fco = lambda_function (lambda_expr);
    tree body = start_lambda_function (fco, lambda_expr);
    bool done = false;
    tree compound_stmt;

    matching_braces braces;
    if (!braces.require_open (parser))
      goto out;

    compound_stmt = begin_compound_stmt (0);

    /* 5.1.1.4 of the standard says:
         If a lambda-expression does not include a trailing-return-type, it
         is as if the trailing-return-type denotes the following type:
	  * if the compound-statement is of the form
               { return attribute-specifier [opt] expression ; }
             the type of the returned expression after lvalue-to-rvalue
             conversion (_conv.lval_ 4.1), array-to-pointer conversion
             (_conv.array_ 4.2), and function-to-pointer conversion
             (_conv.func_ 4.3);
          * otherwise, void.  */

    /* In a lambda that has neither a lambda-return-type-clause
       nor a deducible form, errors should be reported for return statements
       in the body.  Since we used void as the placeholder return type, parsing
       the body as usual will give such desired behavior.  */
    if (is_auto (TREE_TYPE (TREE_TYPE (fco)))
        && cp_lexer_peek_nth_token (parser->lexer, 1)->keyword == RID_RETURN
        && cp_lexer_peek_nth_token (parser->lexer, 2)->type != CPP_SEMICOLON)
      {
	tree expr = NULL_TREE;
	cp_id_kind idk = CP_ID_KIND_NONE;

	/* Parse tentatively in case there's more after the initial return
	   statement.  */
	cp_parser_parse_tentatively (parser);

	cp_parser_require_keyword (parser, RID_RETURN, RT_RETURN);

	expr = cp_parser_expression (parser, &idk);

	cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON);
	braces.require_close (parser);

	if (cp_parser_parse_definitely (parser))
	  {
	    if (!processing_template_decl)
	      {
		tree type = lambda_return_type (expr);
		apply_deduced_return_type (fco, type);
		if (type == error_mark_node)
		  expr = error_mark_node;
	      }

	    /* Will get error here if type not deduced yet.  */
	    finish_return_stmt (expr);

	    done = true;
	  }
      }

    if (!done)
      {
	while (cp_lexer_next_token_is_keyword (parser->lexer, RID_LABEL))
	  cp_parser_label_declaration (parser);
	cp_parser_statement_seq_opt (parser, NULL_TREE);
	braces.require_close (parser);
      }

    finish_compound_stmt (compound_stmt);

  out:
    finish_lambda_function (body);
  }

  restore_omp_privatization_clauses (omp_privatization_save);
  parser->local_variables_forbidden_p = local_variables_forbidden_p;
  parser->in_function_body = in_function_body;
  if (nested)
    pop_function_context();
  else
    --function_depth;
}

/* Statements [gram.stmt.stmt]  */

/* Parse a statement.

   statement:
     labeled-statement
     expression-statement
     compound-statement
     selection-statement
     iteration-statement
     jump-statement
     declaration-statement
     try-block

  C++11:

  statement:
    labeled-statement
    attribute-specifier-seq (opt) expression-statement
    attribute-specifier-seq (opt) compound-statement
    attribute-specifier-seq (opt) selection-statement
    attribute-specifier-seq (opt) iteration-statement
    attribute-specifier-seq (opt) jump-statement
    declaration-statement
    attribute-specifier-seq (opt) try-block

  init-statement:
    expression-statement
    simple-declaration

  TM Extension:

   statement:
     atomic-statement

  IN_COMPOUND is true when the statement is nested inside a
  cp_parser_compound_statement; this matters for certain pragmas.

  If IF_P is not NULL, *IF_P is set to indicate whether the statement
  is a (possibly labeled) if statement which is not enclosed in braces
  and has an else clause.  This is used to implement -Wparentheses.

  CHAIN is a vector of if-else-if conditions.  */

static void
cp_parser_statement (cp_parser* parser, tree in_statement_expr,
		     bool in_compound, bool *if_p, vec<tree> *chain,
		     location_t *loc_after_labels)
{
  tree statement, std_attrs = NULL_TREE;
  cp_token *token;
  location_t statement_location, attrs_location;

 restart:
  if (if_p != NULL)
    *if_p = false;
  /* There is no statement yet.  */
  statement = NULL_TREE;

  saved_token_sentinel saved_tokens (parser->lexer);
  attrs_location = cp_lexer_peek_token (parser->lexer)->location;
  if (c_dialect_objc ())
    /* In obj-c++, seeing '[[' might be the either the beginning of
       c++11 attributes, or a nested objc-message-expression.  So
       let's parse the c++11 attributes tentatively.  */
    cp_parser_parse_tentatively (parser);
  std_attrs = cp_parser_std_attribute_spec_seq (parser);
  if (c_dialect_objc ())
    {
      if (!cp_parser_parse_definitely (parser))
	std_attrs = NULL_TREE;
    }

  /* Peek at the next token.  */
  token = cp_lexer_peek_token (parser->lexer);
  /* Remember the location of the first token in the statement.  */
  statement_location = token->location;
  /* If this is a keyword, then that will often determine what kind of
     statement we have.  */
  if (token->type == CPP_KEYWORD)
    {
      enum rid keyword = token->keyword;

      switch (keyword)
	{
	case RID_CASE:
	case RID_DEFAULT:
	  /* Looks like a labeled-statement with a case label.
	     Parse the label, and then use tail recursion to parse
	     the statement.  */
	  cp_parser_label_for_labeled_statement (parser, std_attrs);
	  in_compound = false;
	  goto restart;

	case RID_IF:
	case RID_SWITCH:
	  statement = cp_parser_selection_statement (parser, if_p, chain);
	  break;

	case RID_WHILE:
	case RID_DO:
	case RID_FOR:
	  statement = cp_parser_iteration_statement (parser, if_p, false);
	  break;

	case RID_CILK_FOR:
	  if (!flag_cilkplus)
	    {
	      error_at (cp_lexer_peek_token (parser->lexer)->location,
			"-fcilkplus must be enabled to use %<_Cilk_for%>");
	      cp_lexer_consume_token (parser->lexer);
	      statement = error_mark_node;
	    }
	  else
	    statement = cp_parser_cilk_for (parser, integer_zero_node, if_p);
	  break;

	case RID_BREAK:
	case RID_CONTINUE:
	case RID_RETURN:
	case RID_GOTO:
	  statement = cp_parser_jump_statement (parser);
	  break;

	case RID_CILK_SYNC:
	  cp_lexer_consume_token (parser->lexer);
	  if (flag_cilkplus)
	    {
	      tree sync_expr = build_cilk_sync ();
	      SET_EXPR_LOCATION (sync_expr,
				 token->location);
	      statement = finish_expr_stmt (sync_expr);
	    }
	  else
	    {
	      error_at (token->location, "-fcilkplus must be enabled to use"
			" %<_Cilk_sync%>");
	      statement = error_mark_node;
	    }
	  cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON);
	  break;

	  /* Objective-C++ exception-handling constructs.  */
	case RID_AT_TRY:
	case RID_AT_CATCH:
	case RID_AT_FINALLY:
	case RID_AT_SYNCHRONIZED:
	case RID_AT_THROW:
	  statement = cp_parser_objc_statement (parser);
	  break;

	case RID_TRY:
	  statement = cp_parser_try_block (parser);
	  break;

	case RID_NAMESPACE:
	  /* This must be a namespace alias definition.  */
	  cp_parser_declaration_statement (parser);
	  return;
	  
	case RID_TRANSACTION_ATOMIC:
	case RID_TRANSACTION_RELAXED:
	case RID_SYNCHRONIZED:
	case RID_ATOMIC_NOEXCEPT:
	case RID_ATOMIC_CANCEL:
	  statement = cp_parser_transaction (parser, token);
	  break;
	case RID_TRANSACTION_CANCEL:
	  statement = cp_parser_transaction_cancel (parser);
	  break;

	default:
	  /* It might be a keyword like `int' that can start a
	     declaration-statement.  */
	  break;
	}
    }
  else if (token->type == CPP_NAME)
    {
      /* If the next token is a `:', then we are looking at a
	 labeled-statement.  */
      token = cp_lexer_peek_nth_token (parser->lexer, 2);
      if (token->type == CPP_COLON)
	{
	  /* Looks like a labeled-statement with an ordinary label.
	     Parse the label, and then use tail recursion to parse
	     the statement.  */

	  cp_parser_label_for_labeled_statement (parser, std_attrs);
	  in_compound = false;
	  goto restart;
	}
    }
  /* Anything that starts with a `{' must be a compound-statement.  */
  else if (token->type == CPP_OPEN_BRACE)
    statement = cp_parser_compound_statement (parser, NULL, BCS_NORMAL, false);
  /* CPP_PRAGMA is a #pragma inside a function body, which constitutes
     a statement all its own.  */
  else if (token->type == CPP_PRAGMA)
    {
      /* Only certain OpenMP pragmas are attached to statements, and thus
	 are considered statements themselves.  All others are not.  In
	 the context of a compound, accept the pragma as a "statement" and
	 return so that we can check for a close brace.  Otherwise we
	 require a real statement and must go back and read one.  */
      if (in_compound)
	cp_parser_pragma (parser, pragma_compound, if_p);
      else if (!cp_parser_pragma (parser, pragma_stmt, if_p))
	goto restart;
      return;
    }
  else if (token->type == CPP_EOF)
    {
      cp_parser_error (parser, "expected statement");
      return;
    }

  /* Everything else must be a declaration-statement or an
     expression-statement.  Try for the declaration-statement
     first, unless we are looking at a `;', in which case we know that
     we have an expression-statement.  */
  if (!statement)
    {
      if (cp_lexer_next_token_is_not (parser->lexer, CPP_SEMICOLON))
	{
	  if (std_attrs != NULL_TREE)
	    {
	      /*  Attributes should be parsed as part of the the
		  declaration, so let's un-parse them.  */
	      saved_tokens.rollback();
	      std_attrs = NULL_TREE;
	    }

	  cp_parser_parse_tentatively (parser);
	  /* Try to parse the declaration-statement.  */
	  cp_parser_declaration_statement (parser);
	  /* If that worked, we're done.  */
	  if (cp_parser_parse_definitely (parser))
	    return;
	}
      /* All preceding labels have been parsed at this point.  */
      if (loc_after_labels != NULL)
	*loc_after_labels = statement_location;

      /* Look for an expression-statement instead.  */
      statement = cp_parser_expression_statement (parser, in_statement_expr);

      /* Handle [[fallthrough]];.  */
      if (attribute_fallthrough_p (std_attrs))
	{
	  /* The next token after the fallthrough attribute is ';'.  */
	  if (statement == NULL_TREE)
	    {
	      /* Turn [[fallthrough]]; into FALLTHROUGH ();.  */
	      statement = build_call_expr_internal_loc (statement_location,
							IFN_FALLTHROUGH,
							void_type_node, 0);
	      finish_expr_stmt (statement);
	    }
	  else
	    warning_at (statement_location, OPT_Wattributes,
			"%<fallthrough%> attribute not followed by %<;%>");
	  std_attrs = NULL_TREE;
	}
    }

  /* Set the line number for the statement.  */
  if (statement && STATEMENT_CODE_P (TREE_CODE (statement)))
    SET_EXPR_LOCATION (statement, statement_location);

  /* Allow "[[fallthrough]];", but warn otherwise.  */
  if (std_attrs != NULL_TREE)
    warning_at (attrs_location,
		OPT_Wattributes,
		"attributes at the beginning of statement are ignored");
}

/* Parse the label for a labeled-statement, i.e.

   identifier :
   case constant-expression :
   default :

   GNU Extension:
   case constant-expression ... constant-expression : statement

   When a label is parsed without errors, the label is added to the
   parse tree by the finish_* functions, so this function doesn't
   have to return the label.  */

static void
cp_parser_label_for_labeled_statement (cp_parser* parser, tree attributes)
{
  cp_token *token;
  tree label = NULL_TREE;
  bool saved_colon_corrects_to_scope_p = parser->colon_corrects_to_scope_p;

  /* The next token should be an identifier.  */
  token = cp_lexer_peek_token (parser->lexer);
  if (token->type != CPP_NAME
      && token->type != CPP_KEYWORD)
    {
      cp_parser_error (parser, "expected labeled-statement");
      return;
    }

  /* Remember whether this case or a user-defined label is allowed to fall
     through to.  */
  bool fallthrough_p = token->flags & PREV_FALLTHROUGH;

  parser->colon_corrects_to_scope_p = false;
  switch (token->keyword)
    {
    case RID_CASE:
      {
	tree expr, expr_hi;
	cp_token *ellipsis;

	/* Consume the `case' token.  */
	cp_lexer_consume_token (parser->lexer);
	/* Parse the constant-expression.  */
	expr = cp_parser_constant_expression (parser);
	if (check_for_bare_parameter_packs (expr))
	  expr = error_mark_node;

	ellipsis = cp_lexer_peek_token (parser->lexer);
	if (ellipsis->type == CPP_ELLIPSIS)
	  {
	    /* Consume the `...' token.  */
	    cp_lexer_consume_token (parser->lexer);
	    expr_hi = cp_parser_constant_expression (parser);
	    if (check_for_bare_parameter_packs (expr_hi))
	      expr_hi = error_mark_node;

	    /* We don't need to emit warnings here, as the common code
	       will do this for us.  */
	  }
	else
	  expr_hi = NULL_TREE;

	if (parser->in_switch_statement_p)
	  {
	    tree l = finish_case_label (token->location, expr, expr_hi);
	    if (l && TREE_CODE (l) == CASE_LABEL_EXPR)
	      FALLTHROUGH_LABEL_P (CASE_LABEL (l)) = fallthrough_p;
	  }
	else
	  error_at (token->location,
		    "case label %qE not within a switch statement",
		    expr);
      }
      break;

    case RID_DEFAULT:
      /* Consume the `default' token.  */
      cp_lexer_consume_token (parser->lexer);

      if (parser->in_switch_statement_p)
	{
	  tree l = finish_case_label (token->location, NULL_TREE, NULL_TREE);
	  if (l && TREE_CODE (l) == CASE_LABEL_EXPR)
	    FALLTHROUGH_LABEL_P (CASE_LABEL (l)) = fallthrough_p;
	}
      else
	error_at (token->location, "case label not within a switch statement");
      break;

    default:
      /* Anything else must be an ordinary label.  */
      label = finish_label_stmt (cp_parser_identifier (parser));
      if (label && TREE_CODE (label) == LABEL_DECL)
	FALLTHROUGH_LABEL_P (label) = fallthrough_p;
      break;
    }

  /* Require the `:' token.  */
  cp_parser_require (parser, CPP_COLON, RT_COLON);

  /* An ordinary label may optionally be followed by attributes.
     However, this is only permitted if the attributes are then
     followed by a semicolon.  This is because, for backward
     compatibility, when parsing
       lab: __attribute__ ((unused)) int i;
     we want the attribute to attach to "i", not "lab".  */
  if (label != NULL_TREE
      && cp_next_tokens_can_be_gnu_attribute_p (parser))
    {
      tree attrs;
      cp_parser_parse_tentatively (parser);
      attrs = cp_parser_gnu_attributes_opt (parser);
      if (attrs == NULL_TREE
	  || cp_lexer_next_token_is_not (parser->lexer, CPP_SEMICOLON))
	cp_parser_abort_tentative_parse (parser);
      else if (!cp_parser_parse_definitely (parser))
	;
      else
	attributes = chainon (attributes, attrs);
    }

  if (attributes != NULL_TREE)
    cplus_decl_attributes (&label, attributes, 0);

  parser->colon_corrects_to_scope_p = saved_colon_corrects_to_scope_p;
}

/* Parse an expression-statement.

   expression-statement:
     expression [opt] ;

   Returns the new EXPR_STMT -- or NULL_TREE if the expression
   statement consists of nothing more than an `;'. IN_STATEMENT_EXPR_P
   indicates whether this expression-statement is part of an
   expression statement.  */

static tree
cp_parser_expression_statement (cp_parser* parser, tree in_statement_expr)
{
  tree statement = NULL_TREE;
  cp_token *token = cp_lexer_peek_token (parser->lexer);
  location_t loc = token->location;

  /* There might be attribute fallthrough.  */
  tree attr = cp_parser_gnu_attributes_opt (parser);

  /* If the next token is a ';', then there is no expression
     statement.  */
  if (cp_lexer_next_token_is_not (parser->lexer, CPP_SEMICOLON))
    {
      statement = cp_parser_expression (parser);
      if (statement == error_mark_node
	  && !cp_parser_uncommitted_to_tentative_parse_p (parser))
	{
	  cp_parser_skip_to_end_of_block_or_statement (parser);
	  return error_mark_node;
	}
    }

  /* Handle [[fallthrough]];.  */
  if (attribute_fallthrough_p (attr))
    {
      /* The next token after the fallthrough attribute is ';'.  */
      if (statement == NULL_TREE)
	/* Turn [[fallthrough]]; into FALLTHROUGH ();.  */
	statement = build_call_expr_internal_loc (loc, IFN_FALLTHROUGH,
						  void_type_node, 0);
      else
	warning_at (loc, OPT_Wattributes,
		    "%<fallthrough%> attribute not followed by %<;%>");
      attr = NULL_TREE;
    }

  /* Allow "[[fallthrough]];", but warn otherwise.  */
  if (attr != NULL_TREE)
    warning_at (loc, OPT_Wattributes,
		"attributes at the beginning of statement are ignored");

  /* Give a helpful message for "A<T>::type t;" and the like.  */
  if (cp_lexer_next_token_is_not (parser->lexer, CPP_SEMICOLON)
      && !cp_parser_uncommitted_to_tentative_parse_p (parser))
    {
      if (TREE_CODE (statement) == SCOPE_REF)
	error_at (token->location, "need %<typename%> before %qE because "
		  "%qT is a dependent scope",
		  statement, TREE_OPERAND (statement, 0));
      else if (is_overloaded_fn (statement)
	       && DECL_CONSTRUCTOR_P (get_first_fn (statement)))
	{
	  /* A::A a; */
	  tree fn = get_first_fn (statement);
	  error_at (token->location,
		    "%<%T::%D%> names the constructor, not the type",
		    DECL_CONTEXT (fn), DECL_NAME (fn));
	}
    }

  /* Consume the final `;'.  */
  cp_parser_consume_semicolon_at_end_of_statement (parser);

  if (in_statement_expr
      && cp_lexer_next_token_is (parser->lexer, CPP_CLOSE_BRACE))
    /* This is the final expression statement of a statement
       expression.  */
    statement = finish_stmt_expr_expr (statement, in_statement_expr);
  else if (statement)
    statement = finish_expr_stmt (statement);

  return statement;
}

/* Parse a compound-statement.

   compound-statement:
     { statement-seq [opt] }

   GNU extension:

   compound-statement:
     { label-declaration-seq [opt] statement-seq [opt] }

   label-declaration-seq:
     label-declaration
     label-declaration-seq label-declaration

   Returns a tree representing the statement.  */

static tree
cp_parser_compound_statement (cp_parser *parser, tree in_statement_expr,
			      int bcs_flags, bool function_body)
{
  tree compound_stmt;
  matching_braces braces;

  /* Consume the `{'.  */
  if (!braces.require_open (parser))
    return error_mark_node;
  if (DECL_DECLARED_CONSTEXPR_P (current_function_decl)
      && !function_body && cxx_dialect < cxx14)
    pedwarn (input_location, OPT_Wpedantic,
	     "compound-statement in constexpr function");
  /* Begin the compound-statement.  */
  compound_stmt = begin_compound_stmt (bcs_flags);
  /* If the next keyword is `__label__' we have a label declaration.  */
  while (cp_lexer_next_token_is_keyword (parser->lexer, RID_LABEL))
    cp_parser_label_declaration (parser);
  /* Parse an (optional) statement-seq.  */
  cp_parser_statement_seq_opt (parser, in_statement_expr);
  /* Finish the compound-statement.  */
  finish_compound_stmt (compound_stmt);
  /* Consume the `}'.  */
  braces.require_close (parser);

  return compound_stmt;
}

/* Parse an (optional) statement-seq.

   statement-seq:
     statement
     statement-seq [opt] statement  */

static void
cp_parser_statement_seq_opt (cp_parser* parser, tree in_statement_expr)
{
  /* Scan statements until there aren't any more.  */
  while (true)
    {
      cp_token *token = cp_lexer_peek_token (parser->lexer);

      /* If we are looking at a `}', then we have run out of
	 statements; the same is true if we have reached the end
	 of file, or have stumbled upon a stray '@end'.  */
      if (token->type == CPP_CLOSE_BRACE
	  || token->type == CPP_EOF
	  || token->type == CPP_PRAGMA_EOL
	  || (token->type == CPP_KEYWORD && token->keyword == RID_AT_END))
	break;
      
      /* If we are in a compound statement and find 'else' then
	 something went wrong.  */
      else if (token->type == CPP_KEYWORD && token->keyword == RID_ELSE)
	{
	  if (parser->in_statement & IN_IF_STMT) 
	    break;
	  else
	    {
	      token = cp_lexer_consume_token (parser->lexer);
	      error_at (token->location, "%<else%> without a previous %<if%>");
	    }
	}

      /* Parse the statement.  */
      cp_parser_statement (parser, in_statement_expr, true, NULL);
    }
}

/* Return true if we're looking at (init; cond), false otherwise.  */

static bool
cp_parser_init_statement_p (cp_parser *parser)
{
  /* Save tokens so that we can put them back.  */
  cp_lexer_save_tokens (parser->lexer);

  /* Look for ';' that is not nested in () or {}.  */
  int ret = cp_parser_skip_to_closing_parenthesis_1 (parser,
						     /*recovering=*/false,
						     CPP_SEMICOLON,
						     /*consume_paren=*/false);

  /* Roll back the tokens we skipped.  */
  cp_lexer_rollback_tokens (parser->lexer);

  return ret == -1;
}

/* Parse a selection-statement.

   selection-statement:
     if ( init-statement [opt] condition ) statement
     if ( init-statement [opt] condition ) statement else statement
     switch ( init-statement [opt] condition ) statement

   Returns the new IF_STMT or SWITCH_STMT.

   If IF_P is not NULL, *IF_P is set to indicate whether the statement
   is a (possibly labeled) if statement which is not enclosed in
   braces and has an else clause.  This is used to implement
   -Wparentheses.

   CHAIN is a vector of if-else-if conditions.  This is used to implement
   -Wduplicated-cond.  */

static tree
cp_parser_selection_statement (cp_parser* parser, bool *if_p,
			       vec<tree> *chain)
{
  cp_token *token;
  enum rid keyword;
  token_indent_info guard_tinfo;

  if (if_p != NULL)
    *if_p = false;

  /* Peek at the next token.  */
  token = cp_parser_require (parser, CPP_KEYWORD, RT_SELECT);
  guard_tinfo = get_token_indent_info (token);

  /* See what kind of keyword it is.  */
  keyword = token->keyword;
  switch (keyword)
    {
    case RID_IF:
    case RID_SWITCH:
      {
	tree statement;
	tree condition;

	bool cx = false;
	if (keyword == RID_IF
	    && cp_lexer_next_token_is_keyword (parser->lexer,
					       RID_CONSTEXPR))
	  {
	    cx = true;
	    cp_token *tok = cp_lexer_consume_token (parser->lexer);
	    if (cxx_dialect < cxx17 && !in_system_header_at (tok->location))
	      pedwarn (tok->location, 0, "%<if constexpr%> only available "
		       "with -std=c++17 or -std=gnu++17");
	  }

	/* Look for the `('.  */
	matching_parens parens;
	if (!parens.require_open (parser))
	  {
	    cp_parser_skip_to_end_of_statement (parser);
	    return error_mark_node;
	  }

	/* Begin the selection-statement.  */
	if (keyword == RID_IF)
	  {
	    statement = begin_if_stmt ();
	    IF_STMT_CONSTEXPR_P (statement) = cx;
	  }
	else
	  statement = begin_switch_stmt ();

	/* Parse the optional init-statement.  */
	if (cp_parser_init_statement_p (parser))
	  {
	    tree decl;
	    if (cxx_dialect < cxx17)
	      pedwarn (cp_lexer_peek_token (parser->lexer)->location, 0,
		       "init-statement in selection statements only available "
		       "with -std=c++17 or -std=gnu++17");
	    cp_parser_init_statement (parser, &decl);
	  }

	/* Parse the condition.  */
	condition = cp_parser_condition (parser);
	/* Look for the `)'.  */
	if (!parens.require_close (parser))
	  cp_parser_skip_to_closing_parenthesis (parser, true, false,
						 /*consume_paren=*/true);

	if (keyword == RID_IF)
	  {
	    bool nested_if;
	    unsigned char in_statement;

	    /* Add the condition.  */
	    condition = finish_if_stmt_cond (condition, statement);

	    if (warn_duplicated_cond)
	      warn_duplicated_cond_add_or_warn (token->location, condition,
						&chain);

	    /* Parse the then-clause.  */
	    in_statement = parser->in_statement;
	    parser->in_statement |= IN_IF_STMT;

	    /* Outside a template, the non-selected branch of a constexpr
	       if is a 'discarded statement', i.e. unevaluated.  */
	    bool was_discarded = in_discarded_stmt;
	    bool discard_then = (cx && !processing_template_decl
				 && integer_zerop (condition));
	    if (discard_then)
	      {
		in_discarded_stmt = true;
		++c_inhibit_evaluation_warnings;
	      }

	    cp_parser_implicitly_scoped_statement (parser, &nested_if,
						   guard_tinfo);

	    parser->in_statement = in_statement;

	    finish_then_clause (statement);

	    if (discard_then)
	      {
		THEN_CLAUSE (statement) = NULL_TREE;
		in_discarded_stmt = was_discarded;
		--c_inhibit_evaluation_warnings;
	      }

	    /* If the next token is `else', parse the else-clause.  */
	    if (cp_lexer_next_token_is_keyword (parser->lexer,
						RID_ELSE))
	      {
		bool discard_else = (cx && !processing_template_decl
				     && integer_nonzerop (condition));
		if (discard_else)
		  {
		    in_discarded_stmt = true;
		    ++c_inhibit_evaluation_warnings;
		  }

		guard_tinfo
		  = get_token_indent_info (cp_lexer_peek_token (parser->lexer));
		/* Consume the `else' keyword.  */
		cp_lexer_consume_token (parser->lexer);
		if (warn_duplicated_cond)
		  {
		    if (cp_lexer_next_token_is_keyword (parser->lexer,
							RID_IF)
			&& chain == NULL)
		      {
			/* We've got "if (COND) else if (COND2)".  Start
			   the condition chain and add COND as the first
			   element.  */
			chain = new vec<tree> ();
			if (!CONSTANT_CLASS_P (condition)
			    && !TREE_SIDE_EFFECTS (condition))
			{
			  /* Wrap it in a NOP_EXPR so that we can set the
			     location of the condition.  */
			  tree e = build1 (NOP_EXPR, TREE_TYPE (condition),
					   condition);
			  SET_EXPR_LOCATION (e, token->location);
			  chain->safe_push (e);
			}
		      }
		    else if (!cp_lexer_next_token_is_keyword (parser->lexer,
							      RID_IF))
		      {
			/* This is if-else without subsequent if.  Zap the
			   condition chain; we would have already warned at
			   this point.  */
			delete chain;
			chain = NULL;
		      }
		  }
		begin_else_clause (statement);
		/* Parse the else-clause.  */
		cp_parser_implicitly_scoped_statement (parser, NULL,
						       guard_tinfo, chain);

		finish_else_clause (statement);

		/* If we are currently parsing a then-clause, then
		   IF_P will not be NULL.  We set it to true to
		   indicate that this if statement has an else clause.
		   This may trigger the Wparentheses warning below
		   when we get back up to the parent if statement.  */
		if (if_p != NULL)
		  *if_p = true;

		if (discard_else)
		  {
		    ELSE_CLAUSE (statement) = NULL_TREE;
		    in_discarded_stmt = was_discarded;
		    --c_inhibit_evaluation_warnings;
		  }
	      }
	    else
	      {
		/* This if statement does not have an else clause.  If
		   NESTED_IF is true, then the then-clause has an if
		   statement which does have an else clause.  We warn
		   about the potential ambiguity.  */
		if (nested_if)
		  warning_at (EXPR_LOCATION (statement), OPT_Wdangling_else,
			      "suggest explicit braces to avoid ambiguous"
			      " %<else%>");
		if (warn_duplicated_cond)
		  {
		    /* We don't need the condition chain anymore.  */
		    delete chain;
		    chain = NULL;
		  }
	      }

	    /* Now we're all done with the if-statement.  */
	    finish_if_stmt (statement);
	  }
	else
	  {
	    bool in_switch_statement_p;
	    unsigned char in_statement;

	    /* Add the condition.  */
	    finish_switch_cond (condition, statement);

	    /* Parse the body of the switch-statement.  */
	    in_switch_statement_p = parser->in_switch_statement_p;
	    in_statement = parser->in_statement;
	    parser->in_switch_statement_p = true;
	    parser->in_statement |= IN_SWITCH_STMT;
	    cp_parser_implicitly_scoped_statement (parser, if_p,
						   guard_tinfo);
	    parser->in_switch_statement_p = in_switch_statement_p;
	    parser->in_statement = in_statement;

	    /* Now we're all done with the switch-statement.  */
	    finish_switch_stmt (statement);
	  }

	return statement;
      }
      break;

    default:
      cp_parser_error (parser, "expected selection-statement");
      return error_mark_node;
    }
}

/* Parse a condition.

   condition:
     expression
     type-specifier-seq declarator = initializer-clause
     type-specifier-seq declarator braced-init-list

   GNU Extension:

   condition:
     type-specifier-seq declarator asm-specification [opt]
       attributes [opt] = assignment-expression

   Returns the expression that should be tested.  */

static tree
cp_parser_condition (cp_parser* parser)
{
  cp_decl_specifier_seq type_specifiers;
  const char *saved_message;
  int declares_class_or_enum;

  /* Try the declaration first.  */
  cp_parser_parse_tentatively (parser);
  /* New types are not allowed in the type-specifier-seq for a
     condition.  */
  saved_message = parser->type_definition_forbidden_message;
  parser->type_definition_forbidden_message
    = G_("types may not be defined in conditions");
  /* Parse the type-specifier-seq.  */
  cp_parser_decl_specifier_seq (parser,
				CP_PARSER_FLAGS_ONLY_TYPE_OR_CONSTEXPR,
				&type_specifiers,
				&declares_class_or_enum);
  /* Restore the saved message.  */
  parser->type_definition_forbidden_message = saved_message;
  /* If all is well, we might be looking at a declaration.  */
  if (!cp_parser_error_occurred (parser))
    {
      tree decl;
      tree asm_specification;
      tree attributes;
      cp_declarator *declarator;
      tree initializer = NULL_TREE;

      /* Parse the declarator.  */
      declarator = cp_parser_declarator (parser, CP_PARSER_DECLARATOR_NAMED,
					 /*ctor_dtor_or_conv_p=*/NULL,
					 /*parenthesized_p=*/NULL,
					 /*member_p=*/false,
					 /*friend_p=*/false);
      /* Parse the attributes.  */
      attributes = cp_parser_attributes_opt (parser);
      /* Parse the asm-specification.  */
      asm_specification = cp_parser_asm_specification_opt (parser);
      /* If the next token is not an `=' or '{', then we might still be
	 looking at an expression.  For example:

	   if (A(a).x)

	 looks like a decl-specifier-seq and a declarator -- but then
	 there is no `=', so this is an expression.  */
      if (cp_lexer_next_token_is_not (parser->lexer, CPP_EQ)
	  && cp_lexer_next_token_is_not (parser->lexer, CPP_OPEN_BRACE))
	cp_parser_simulate_error (parser);
	
      /* If we did see an `=' or '{', then we are looking at a declaration
	 for sure.  */
      if (cp_parser_parse_definitely (parser))
	{
	  tree pushed_scope;
	  bool non_constant_p;
	  int flags = LOOKUP_ONLYCONVERTING;

	  /* Create the declaration.  */
	  decl = start_decl (declarator, &type_specifiers,
			     /*initialized_p=*/true,
			     attributes, /*prefix_attributes=*/NULL_TREE,
			     &pushed_scope);

	  /* Parse the initializer.  */
	  if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_BRACE))
	    {
	      initializer = cp_parser_braced_list (parser, &non_constant_p);
	      CONSTRUCTOR_IS_DIRECT_INIT (initializer) = 1;
	      flags = 0;
	    }
	  else
	    {
	      /* Consume the `='.  */
	      cp_parser_require (parser, CPP_EQ, RT_EQ);
	      initializer = cp_parser_initializer_clause (parser, &non_constant_p);
	    }
	  if (BRACE_ENCLOSED_INITIALIZER_P (initializer))
	    maybe_warn_cpp0x (CPP0X_INITIALIZER_LISTS);

	  /* Process the initializer.  */
	  cp_finish_decl (decl,
			  initializer, !non_constant_p,
			  asm_specification,
			  flags);

	  if (pushed_scope)
	    pop_scope (pushed_scope);

	  return convert_from_reference (decl);
	}
    }
  /* If we didn't even get past the declarator successfully, we are
     definitely not looking at a declaration.  */
  else
    cp_parser_abort_tentative_parse (parser);

  /* Otherwise, we are looking at an expression.  */
  return cp_parser_expression (parser);
}

/* Parses a for-statement or range-for-statement until the closing ')',
   not included. */

static tree
cp_parser_for (cp_parser *parser, bool ivdep)
{
  tree init, scope, decl;
  bool is_range_for;

  /* Begin the for-statement.  */
  scope = begin_for_scope (&init);

  /* Parse the initialization.  */
  is_range_for = cp_parser_init_statement (parser, &decl);

  if (is_range_for)
    return cp_parser_range_for (parser, scope, init, decl, ivdep);
  else
    return cp_parser_c_for (parser, scope, init, ivdep);
}

static tree
cp_parser_c_for (cp_parser *parser, tree scope, tree init, bool ivdep)
{
  /* Normal for loop */
  tree condition = NULL_TREE;
  tree expression = NULL_TREE;
  tree stmt;

  stmt = begin_for_stmt (scope, init);
  /* The init-statement has already been parsed in
     cp_parser_init_statement, so no work is needed here.  */
  finish_init_stmt (stmt);

  /* If there's a condition, process it.  */
  if (cp_lexer_next_token_is_not (parser->lexer, CPP_SEMICOLON))
    condition = cp_parser_condition (parser);
  else if (ivdep)
    {
      cp_parser_error (parser, "missing loop condition in loop with "
		       "%<GCC ivdep%> pragma");
      condition = error_mark_node;
    }
  finish_for_cond (condition, stmt, ivdep);
  /* Look for the `;'.  */
  cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON);

  /* If there's an expression, process it.  */
  if (cp_lexer_next_token_is_not (parser->lexer, CPP_CLOSE_PAREN))
    expression = cp_parser_expression (parser);
  finish_for_expr (expression, stmt);

  return stmt;
}

/* Tries to parse a range-based for-statement:

  range-based-for:
    decl-specifier-seq declarator : expression

  The decl-specifier-seq declarator and the `:' are already parsed by
  cp_parser_init_statement.  If processing_template_decl it returns a
  newly created RANGE_FOR_STMT; if not, it is converted to a
  regular FOR_STMT.  */

static tree
cp_parser_range_for (cp_parser *parser, tree scope, tree init, tree range_decl,
		     bool ivdep)
{
  tree stmt, range_expr;
  auto_vec <cxx_binding *, 16> bindings;
  auto_vec <tree, 16> names;
  tree decomp_first_name = NULL_TREE;
  unsigned int decomp_cnt = 0;

  /* Get the range declaration momentarily out of the way so that
     the range expression doesn't clash with it. */
  if (range_decl != error_mark_node)
    {
      if (DECL_HAS_VALUE_EXPR_P (range_decl))
	{
	  tree v = DECL_VALUE_EXPR (range_decl);
	  /* For decomposition declaration get all of the corresponding
	     declarations out of the way.  */
	  if (TREE_CODE (v) == ARRAY_REF
	      && VAR_P (TREE_OPERAND (v, 0))
	      && DECL_DECOMPOSITION_P (TREE_OPERAND (v, 0)))
	    {
	      tree d = range_decl;
	      range_decl = TREE_OPERAND (v, 0);
	      decomp_cnt = tree_to_uhwi (TREE_OPERAND (v, 1)) + 1;
	      decomp_first_name = d;
	      for (unsigned int i = 0; i < decomp_cnt; i++, d = DECL_CHAIN (d))
		{
		  tree name = DECL_NAME (d);
		  names.safe_push (name);
		  bindings.safe_push (IDENTIFIER_BINDING (name));
		  IDENTIFIER_BINDING (name)
		    = IDENTIFIER_BINDING (name)->previous;
		}
	    }
	}
      if (names.is_empty ())
	{
	  tree name = DECL_NAME (range_decl);
	  names.safe_push (name);
	  bindings.safe_push (IDENTIFIER_BINDING (name));
	  IDENTIFIER_BINDING (name) = IDENTIFIER_BINDING (name)->previous;
	}
    }

  if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_BRACE))
    {
      bool expr_non_constant_p;
      range_expr = cp_parser_braced_list (parser, &expr_non_constant_p);
    }
  else
    range_expr = cp_parser_expression (parser);

  /* Put the range declaration(s) back into scope. */
  for (unsigned int i = 0; i < names.length (); i++)
    {
      cxx_binding *binding = bindings[i];
      binding->previous = IDENTIFIER_BINDING (names[i]);
      IDENTIFIER_BINDING (names[i]) = binding;
    }

  /* If in template, STMT is converted to a normal for-statement
     at instantiation. If not, it is done just ahead. */
  if (processing_template_decl)
    {
      if (check_for_bare_parameter_packs (range_expr))
	range_expr = error_mark_node;
      stmt = begin_range_for_stmt (scope, init);
      if (ivdep)
	RANGE_FOR_IVDEP (stmt) = 1;
      finish_range_for_decl (stmt, range_decl, range_expr);
      if (!type_dependent_expression_p (range_expr)
	  /* do_auto_deduction doesn't mess with template init-lists.  */
	  && !BRACE_ENCLOSED_INITIALIZER_P (range_expr))
	do_range_for_auto_deduction (range_decl, range_expr);
    }
  else
    {
      stmt = begin_for_stmt (scope, init);
      stmt = cp_convert_range_for (stmt, range_decl, range_expr,
				   decomp_first_name, decomp_cnt, ivdep);
    }
  return stmt;
}

/* Subroutine of cp_convert_range_for: given the initializer expression,
   builds up the range temporary.  */

static tree
build_range_temp (tree range_expr)
{
  tree range_type, range_temp;

  /* Find out the type deduced by the declaration
     `auto &&__range = range_expr'.  */
  range_type = cp_build_reference_type (make_auto (), true);
  range_type = do_auto_deduction (range_type, range_expr,
				  type_uses_auto (range_type));

  /* Create the __range variable.  */
  range_temp = build_decl (input_location, VAR_DECL,
			   get_identifier ("__for_range"), range_type);
  TREE_USED (range_temp) = 1;
  DECL_ARTIFICIAL (range_temp) = 1;

  return range_temp;
}

/* Used by cp_parser_range_for in template context: we aren't going to
   do a full conversion yet, but we still need to resolve auto in the
   type of the for-range-declaration if present.  This is basically
   a shortcut version of cp_convert_range_for.  */

static void
do_range_for_auto_deduction (tree decl, tree range_expr)
{
  tree auto_node = type_uses_auto (TREE_TYPE (decl));
  if (auto_node)
    {
      tree begin_dummy, end_dummy, range_temp, iter_type, iter_decl;
      range_temp = convert_from_reference (build_range_temp (range_expr));
      iter_type = (cp_parser_perform_range_for_lookup
		   (range_temp, &begin_dummy, &end_dummy));
      if (iter_type)
	{
	  iter_decl = build_decl (input_location, VAR_DECL, NULL_TREE,
				  iter_type);
	  iter_decl = build_x_indirect_ref (input_location, iter_decl, RO_NULL,
					    tf_warning_or_error);
	  TREE_TYPE (decl) = do_auto_deduction (TREE_TYPE (decl),
						iter_decl, auto_node);
	}
    }
}

/* Converts a range-based for-statement into a normal
   for-statement, as per the definition.

      for (RANGE_DECL : RANGE_EXPR)
	BLOCK

   should be equivalent to:

      {
	auto &&__range = RANGE_EXPR;
	for (auto __begin = BEGIN_EXPR, end = END_EXPR;
	      __begin != __end;
	      ++__begin)
	  {
	      RANGE_DECL = *__begin;
	      BLOCK
	  }
      }

   If RANGE_EXPR is an array:
	BEGIN_EXPR = __range
	END_EXPR = __range + ARRAY_SIZE(__range)
   Else if RANGE_EXPR has a member 'begin' or 'end':
	BEGIN_EXPR = __range.begin()
	END_EXPR = __range.end()
   Else:
	BEGIN_EXPR = begin(__range)
	END_EXPR = end(__range);

   If __range has a member 'begin' but not 'end', or vice versa, we must
   still use the second alternative (it will surely fail, however).
   When calling begin()/end() in the third alternative we must use
   argument dependent lookup, but always considering 'std' as an associated
   namespace.  */

tree
cp_convert_range_for (tree statement, tree range_decl, tree range_expr,
		      tree decomp_first_name, unsigned int decomp_cnt,
		      bool ivdep)
{
  tree begin, end;
  tree iter_type, begin_expr, end_expr;
  tree condition, expression;

  range_expr = mark_lvalue_use (range_expr);

  if (range_decl == error_mark_node || range_expr == error_mark_node)
    /* If an error happened previously do nothing or else a lot of
       unhelpful errors would be issued.  */
    begin_expr = end_expr = iter_type = error_mark_node;
  else
    {
      tree range_temp;

      if (VAR_P (range_expr)
	  && array_of_runtime_bound_p (TREE_TYPE (range_expr)))
	/* Can't bind a reference to an array of runtime bound.  */
	range_temp = range_expr;
      else
	{
	  range_temp = build_range_temp (range_expr);
	  pushdecl (range_temp);
	  cp_finish_decl (range_temp, range_expr,
			  /*is_constant_init*/false, NULL_TREE,
			  LOOKUP_ONLYCONVERTING);
	  range_temp = convert_from_reference (range_temp);
	}
      iter_type = cp_parser_perform_range_for_lookup (range_temp,
						      &begin_expr, &end_expr);
    }

  /* The new for initialization statement.  */
  begin = build_decl (input_location, VAR_DECL,
		      get_identifier ("__for_begin"), iter_type);
  TREE_USED (begin) = 1;
  DECL_ARTIFICIAL (begin) = 1;
  pushdecl (begin);
  cp_finish_decl (begin, begin_expr,
		  /*is_constant_init*/false, NULL_TREE,
		  LOOKUP_ONLYCONVERTING);

  if (cxx_dialect >= cxx17)
    iter_type = cv_unqualified (TREE_TYPE (end_expr));
  end = build_decl (input_location, VAR_DECL,
		    get_identifier ("__for_end"), iter_type);
  TREE_USED (end) = 1;
  DECL_ARTIFICIAL (end) = 1;
  pushdecl (end);
  cp_finish_decl (end, end_expr,
		  /*is_constant_init*/false, NULL_TREE,
		  LOOKUP_ONLYCONVERTING);

  finish_init_stmt (statement);

  /* The new for condition.  */
  condition = build_x_binary_op (input_location, NE_EXPR,
				 begin, ERROR_MARK,
				 end, ERROR_MARK,
				 NULL, tf_warning_or_error);
  finish_for_cond (condition, statement, ivdep);

  /* The new increment expression.  */
  expression = finish_unary_op_expr (input_location,
				     PREINCREMENT_EXPR, begin,
				     tf_warning_or_error);
  finish_for_expr (expression, statement);

  /* The declaration is initialized with *__begin inside the loop body.  */
  cp_finish_decl (range_decl,
		  build_x_indirect_ref (input_location, begin, RO_NULL,
					tf_warning_or_error),
		  /*is_constant_init*/false, NULL_TREE,
		  LOOKUP_ONLYCONVERTING);
  if (VAR_P (range_decl) && DECL_DECOMPOSITION_P (range_decl))
    cp_finish_decomp (range_decl, decomp_first_name, decomp_cnt);

  return statement;
}

/* Solves BEGIN_EXPR and END_EXPR as described in cp_convert_range_for.
   We need to solve both at the same time because the method used
   depends on the existence of members begin or end.
   Returns the type deduced for the iterator expression.  */

static tree
cp_parser_perform_range_for_lookup (tree range, tree *begin, tree *end)
{
  if (error_operand_p (range))
    {
      *begin = *end = error_mark_node;
      return error_mark_node;
    }

  if (!COMPLETE_TYPE_P (complete_type (TREE_TYPE (range))))
    {
      error ("range-based %<for%> expression of type %qT "
	     "has incomplete type", TREE_TYPE (range));
      *begin = *end = error_mark_node;
      return error_mark_node;
    }
  if (TREE_CODE (TREE_TYPE (range)) == ARRAY_TYPE)
    {
      /* If RANGE is an array, we will use pointer arithmetic.  */
      *begin = decay_conversion (range, tf_warning_or_error);
      *end = build_binary_op (input_location, PLUS_EXPR,
			      range,
			      array_type_nelts_top (TREE_TYPE (range)),
			      false);
      return TREE_TYPE (*begin);
    }
  else
    {
      /* If it is not an array, we must do a bit of magic.  */
      tree id_begin, id_end;
      tree member_begin, member_end;

      *begin = *end = error_mark_node;

      id_begin = get_identifier ("begin");
      id_end = get_identifier ("end");
      member_begin = lookup_member (TREE_TYPE (range), id_begin,
				    /*protect=*/2, /*want_type=*/false,
				    tf_warning_or_error);
      member_end = lookup_member (TREE_TYPE (range), id_end,
				  /*protect=*/2, /*want_type=*/false,
				  tf_warning_or_error);

      if (member_begin != NULL_TREE || member_end != NULL_TREE)
	{
	  /* Use the member functions.  */
	  if (member_begin != NULL_TREE)
	    *begin = cp_parser_range_for_member_function (range, id_begin);
	  else
	    error ("range-based %<for%> expression of type %qT has an "
		   "%<end%> member but not a %<begin%>", TREE_TYPE (range));

	  if (member_end != NULL_TREE)
	    *end = cp_parser_range_for_member_function (range, id_end);
	  else
	    error ("range-based %<for%> expression of type %qT has a "
		   "%<begin%> member but not an %<end%>", TREE_TYPE (range));
	}
      else
	{
	  /* Use global functions with ADL.  */
	  vec<tree, va_gc> *vec;
	  vec = make_tree_vector ();

	  vec_safe_push (vec, range);

	  member_begin = perform_koenig_lookup (id_begin, vec,
						tf_warning_or_error);
	  *begin = finish_call_expr (member_begin, &vec, false, true,
				     tf_warning_or_error);
	  member_end = perform_koenig_lookup (id_end, vec,
					      tf_warning_or_error);
	  *end = finish_call_expr (member_end, &vec, false, true,
				   tf_warning_or_error);

	  release_tree_vector (vec);
	}

      /* Last common checks.  */
      if (*begin == error_mark_node || *end == error_mark_node)
	{
	  /* If one of the expressions is an error do no more checks.  */
	  *begin = *end = error_mark_node;
	  return error_mark_node;
	}
      else if (type_dependent_expression_p (*begin)
	       || type_dependent_expression_p (*end))
	/* Can happen, when, eg, in a template context, Koenig lookup
	   can't resolve begin/end (c++/58503).  */
	return NULL_TREE;
      else
	{
	  tree iter_type = cv_unqualified (TREE_TYPE (*begin));
	  /* The unqualified type of the __begin and __end temporaries should
	     be the same, as required by the multiple auto declaration.  */
	  if (!same_type_p (iter_type, cv_unqualified (TREE_TYPE (*end))))
	    {
	      if (cxx_dialect >= cxx17
		  && (build_x_binary_op (input_location, NE_EXPR,
					 *begin, ERROR_MARK,
					 *end, ERROR_MARK,
					 NULL, tf_none)
		      != error_mark_node))
		/* P0184R0 allows __begin and __end to have different types,
		   but make sure they are comparable so we can give a better
		   diagnostic.  */;
	      else
		error ("inconsistent begin/end types in range-based %<for%> "
		       "statement: %qT and %qT",
		       TREE_TYPE (*begin), TREE_TYPE (*end));
	    }
	  return iter_type;
	}
    }
}

/* Helper function for cp_parser_perform_range_for_lookup.
   Builds a tree for RANGE.IDENTIFIER().  */

static tree
cp_parser_range_for_member_function (tree range, tree identifier)
{
  tree member, res;
  vec<tree, va_gc> *vec;

  member = finish_class_member_access_expr (range, identifier,
					    false, tf_warning_or_error);
  if (member == error_mark_node)
    return error_mark_node;

  vec = make_tree_vector ();
  res = finish_call_expr (member, &vec,
			  /*disallow_virtual=*/false,
			  /*koenig_p=*/false,
			  tf_warning_or_error);
  release_tree_vector (vec);
  return res;
}

/* Parse an iteration-statement.

   iteration-statement:
     while ( condition ) statement
     do statement while ( expression ) ;
     for ( init-statement condition [opt] ; expression [opt] )
       statement

   Returns the new WHILE_STMT, DO_STMT, FOR_STMT or RANGE_FOR_STMT.  */

static tree
cp_parser_iteration_statement (cp_parser* parser, bool *if_p, bool ivdep)
{
  cp_token *token;
  enum rid keyword;
  tree statement;
  unsigned char in_statement;
  token_indent_info guard_tinfo;

  /* Peek at the next token.  */
  token = cp_parser_require (parser, CPP_KEYWORD, RT_ITERATION);
  if (!token)
    return error_mark_node;

  guard_tinfo = get_token_indent_info (token);

  /* Remember whether or not we are already within an iteration
     statement.  */
  in_statement = parser->in_statement;

  /* See what kind of keyword it is.  */
  keyword = token->keyword;
  switch (keyword)
    {
    case RID_WHILE:
      {
	tree condition;

	/* Begin the while-statement.  */
	statement = begin_while_stmt ();
	/* Look for the `('.  */
	matching_parens parens;
	parens.require_open (parser);
	/* Parse the condition.  */
	condition = cp_parser_condition (parser);
	finish_while_stmt_cond (condition, statement, ivdep);
	/* Look for the `)'.  */
	parens.require_close (parser);
	/* Parse the dependent statement.  */
	parser->in_statement = IN_ITERATION_STMT;
	cp_parser_already_scoped_statement (parser, if_p, guard_tinfo);
	parser->in_statement = in_statement;
	/* We're done with the while-statement.  */
	finish_while_stmt (statement);
      }
      break;

    case RID_DO:
      {
	tree expression;

	/* Begin the do-statement.  */
	statement = begin_do_stmt ();
	/* Parse the body of the do-statement.  */
	parser->in_statement = IN_ITERATION_STMT;
	cp_parser_implicitly_scoped_statement (parser, NULL, guard_tinfo);
	parser->in_statement = in_statement;
	finish_do_body (statement);
	/* Look for the `while' keyword.  */
	cp_parser_require_keyword (parser, RID_WHILE, RT_WHILE);
	/* Look for the `('.  */
	matching_parens parens;
	parens.require_open (parser);
	/* Parse the expression.  */
	expression = cp_parser_expression (parser);
	/* We're done with the do-statement.  */
	finish_do_stmt (expression, statement, ivdep);
	/* Look for the `)'.  */
	parens.require_close (parser);
	/* Look for the `;'.  */
	cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON);
      }
      break;

    case RID_FOR:
      {
	/* Look for the `('.  */
	matching_parens parens;
	parens.require_open (parser);

	statement = cp_parser_for (parser, ivdep);

	/* Look for the `)'.  */
	parens.require_close (parser);

	/* Parse the body of the for-statement.  */
	parser->in_statement = IN_ITERATION_STMT;
	cp_parser_already_scoped_statement (parser, if_p, guard_tinfo);
	parser->in_statement = in_statement;

	/* We're done with the for-statement.  */
	finish_for_stmt (statement);
      }
      break;

    default:
      cp_parser_error (parser, "expected iteration-statement");
      statement = error_mark_node;
      break;
    }

  return statement;
}

/* Parse a init-statement or the declarator of a range-based-for.
   Returns true if a range-based-for declaration is seen.

   init-statement:
     expression-statement
     simple-declaration  */

static bool
cp_parser_init_statement (cp_parser* parser, tree *decl)
{
  /* If the next token is a `;', then we have an empty
     expression-statement.  Grammatically, this is also a
     simple-declaration, but an invalid one, because it does not
     declare anything.  Therefore, if we did not handle this case
     specially, we would issue an error message about an invalid
     declaration.  */
  if (cp_lexer_next_token_is_not (parser->lexer, CPP_SEMICOLON))
    {
      bool is_range_for = false;
      bool saved_colon_corrects_to_scope_p = parser->colon_corrects_to_scope_p;

      /* A colon is used in range-based for.  */
      parser->colon_corrects_to_scope_p = false;

      /* We're going to speculatively look for a declaration, falling back
	 to an expression, if necessary.  */
      cp_parser_parse_tentatively (parser);
      /* Parse the declaration.  */
      cp_parser_simple_declaration (parser,
				    /*function_definition_allowed_p=*/false,
				    decl);
      parser->colon_corrects_to_scope_p = saved_colon_corrects_to_scope_p;
      if (cp_lexer_next_token_is (parser->lexer, CPP_COLON))
	{
	  /* It is a range-for, consume the ':' */
	  cp_lexer_consume_token (parser->lexer);
	  is_range_for = true;
	  if (cxx_dialect < cxx11)
	    {
	      pedwarn (cp_lexer_peek_token (parser->lexer)->location, 0,
		       "range-based %<for%> loops only available with "
		       "-std=c++11 or -std=gnu++11");
	      *decl = error_mark_node;
	    }
	}
      else
	  /* The ';' is not consumed yet because we told
	     cp_parser_simple_declaration not to.  */
	  cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON);

      if (cp_parser_parse_definitely (parser))
	return is_range_for;
      /* If the tentative parse failed, then we shall need to look for an
	 expression-statement.  */
    }
  /* If we are here, it is an expression-statement.  */
  cp_parser_expression_statement (parser, NULL_TREE);
  return false;
}

/* Parse a jump-statement.

   jump-statement:
     break ;
     continue ;
     return expression [opt] ;
     return braced-init-list ;
     goto identifier ;

   GNU extension:

   jump-statement:
     goto * expression ;

   Returns the new BREAK_STMT, CONTINUE_STMT, RETURN_EXPR, or GOTO_EXPR.  */

static tree
cp_parser_jump_statement (cp_parser* parser)
{
  tree statement = error_mark_node;
  cp_token *token;
  enum rid keyword;
  unsigned char in_statement;

  /* Peek at the next token.  */
  token = cp_parser_require (parser, CPP_KEYWORD, RT_JUMP);
  if (!token)
    return error_mark_node;

  /* See what kind of keyword it is.  */
  keyword = token->keyword;
  switch (keyword)
    {
    case RID_BREAK:
      in_statement = parser->in_statement & ~IN_IF_STMT;      
      switch (in_statement)
	{
	case 0:
	  error_at (token->location, "break statement not within loop or switch");
	  break;
	default:
	  gcc_assert ((in_statement & IN_SWITCH_STMT)
		      || in_statement == IN_ITERATION_STMT);
	  statement = finish_break_stmt ();
	  if (in_statement == IN_ITERATION_STMT)
	    break_maybe_infinite_loop ();
	  break;
	case IN_OMP_BLOCK:
	  error_at (token->location, "invalid exit from OpenMP structured block");
	  break;
	case IN_OMP_FOR:
	  error_at (token->location, "break statement used with OpenMP for loop");
	  break;
	case IN_CILK_SIMD_FOR:
	  error_at (token->location, "break statement used with Cilk Plus for loop");
	  break;
	}
      cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON);
      break;

    case RID_CONTINUE:
      switch (parser->in_statement & ~(IN_SWITCH_STMT | IN_IF_STMT))
	{
	case 0:
	  error_at (token->location, "continue statement not within a loop");
	  break;
	case IN_CILK_SIMD_FOR:
	  error_at (token->location,
		    "continue statement within %<#pragma simd%> loop body");
	  /* Fall through.  */
	case IN_ITERATION_STMT:
	case IN_OMP_FOR:
	  statement = finish_continue_stmt ();
	  break;
	case IN_OMP_BLOCK:
	  error_at (token->location, "invalid exit from OpenMP structured block");
	  break;
	default:
	  gcc_unreachable ();
	}
      cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON);
      break;

    case RID_RETURN:
      {
	tree expr;
	bool expr_non_constant_p;

	if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_BRACE))
	  {
	    cp_lexer_set_source_position (parser->lexer);
	    maybe_warn_cpp0x (CPP0X_INITIALIZER_LISTS);
	    expr = cp_parser_braced_list (parser, &expr_non_constant_p);
	  }
	else if (cp_lexer_next_token_is_not (parser->lexer, CPP_SEMICOLON))
	  expr = cp_parser_expression (parser);
	else
	  /* If the next token is a `;', then there is no
	     expression.  */
	  expr = NULL_TREE;
	/* Build the return-statement.  */
	if (current_function_auto_return_pattern && in_discarded_stmt)
	  /* Don't deduce from a discarded return statement.  */;
	else
	  statement = finish_return_stmt (expr);
	/* Look for the final `;'.  */
	cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON);
      }
      break;

    case RID_GOTO:
      if (parser->in_function_body
	  && DECL_DECLARED_CONSTEXPR_P (current_function_decl))
	{
	  error ("%<goto%> in %<constexpr%> function");
	  cp_function_chain->invalid_constexpr = true;
	}

      /* Create the goto-statement.  */
      if (cp_lexer_next_token_is (parser->lexer, CPP_MULT))
	{
	  /* Issue a warning about this use of a GNU extension.  */
	  pedwarn (token->location, OPT_Wpedantic, "ISO C++ forbids computed gotos");
	  /* Consume the '*' token.  */
	  cp_lexer_consume_token (parser->lexer);
	  /* Parse the dependent expression.  */
	  finish_goto_stmt (cp_parser_expression (parser));
	}
      else
	finish_goto_stmt (cp_parser_identifier (parser));
      /* Look for the final `;'.  */
      cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON);
      break;

    default:
      cp_parser_error (parser, "expected jump-statement");
      break;
    }

  return statement;
}

/* Parse a declaration-statement.

   declaration-statement:
     block-declaration  */

static void
cp_parser_declaration_statement (cp_parser* parser)
{
  void *p;

  /* Get the high-water mark for the DECLARATOR_OBSTACK.  */
  p = obstack_alloc (&declarator_obstack, 0);

 /* Parse the block-declaration.  */
  cp_parser_block_declaration (parser, /*statement_p=*/true);

  /* Free any declarators allocated.  */
  obstack_free (&declarator_obstack, p);
}

/* Some dependent statements (like `if (cond) statement'), are
   implicitly in their own scope.  In other words, if the statement is
   a single statement (as opposed to a compound-statement), it is
   none-the-less treated as if it were enclosed in braces.  Any
   declarations appearing in the dependent statement are out of scope
   after control passes that point.  This function parses a statement,
   but ensures that is in its own scope, even if it is not a
   compound-statement.

   If IF_P is not NULL, *IF_P is set to indicate whether the statement
   is a (possibly labeled) if statement which is not enclosed in
   braces and has an else clause.  This is used to implement
   -Wparentheses.

   CHAIN is a vector of if-else-if conditions.  This is used to implement
   -Wduplicated-cond.

   Returns the new statement.  */

static tree
cp_parser_implicitly_scoped_statement (cp_parser* parser, bool *if_p,
				       const token_indent_info &guard_tinfo,
				       vec<tree> *chain)
{
  tree statement;
  location_t body_loc = cp_lexer_peek_token (parser->lexer)->location;
  location_t body_loc_after_labels = UNKNOWN_LOCATION;
  token_indent_info body_tinfo
    = get_token_indent_info (cp_lexer_peek_token (parser->lexer));

  if (if_p != NULL)
    *if_p = false;

  /* Mark if () ; with a special NOP_EXPR.  */
  if (cp_lexer_next_token_is (parser->lexer, CPP_SEMICOLON))
    {
      cp_lexer_consume_token (parser->lexer);
      statement = add_stmt (build_empty_stmt (body_loc));

      if (guard_tinfo.keyword == RID_IF
	  && !cp_lexer_next_token_is_keyword (parser->lexer, RID_ELSE))
	warning_at (body_loc, OPT_Wempty_body,
		    "suggest braces around empty body in an %<if%> statement");
      else if (guard_tinfo.keyword == RID_ELSE)
	warning_at (body_loc, OPT_Wempty_body,
		    "suggest braces around empty body in an %<else%> statement");
    }
  /* if a compound is opened, we simply parse the statement directly.  */
  else if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_BRACE))
    statement = cp_parser_compound_statement (parser, NULL, BCS_NORMAL, false);
  /* If the token is not a `{', then we must take special action.  */
  else
    {
      /* Create a compound-statement.  */
      statement = begin_compound_stmt (0);
      /* Parse the dependent-statement.  */
      cp_parser_statement (parser, NULL_TREE, false, if_p, chain,
			   &body_loc_after_labels);
      /* Finish the dummy compound-statement.  */
      finish_compound_stmt (statement);
    }

  token_indent_info next_tinfo
    = get_token_indent_info (cp_lexer_peek_token (parser->lexer));
  warn_for_misleading_indentation (guard_tinfo, body_tinfo, next_tinfo);

  if (body_loc_after_labels != UNKNOWN_LOCATION
      && next_tinfo.type != CPP_SEMICOLON)
    warn_for_multistatement_macros (body_loc_after_labels, next_tinfo.location,
				    guard_tinfo.location, guard_tinfo.keyword);

  /* Return the statement.  */
  return statement;
}

/* For some dependent statements (like `while (cond) statement'), we
   have already created a scope.  Therefore, even if the dependent
   statement is a compound-statement, we do not want to create another
   scope.  */

static void
cp_parser_already_scoped_statement (cp_parser* parser, bool *if_p,
				    const token_indent_info &guard_tinfo)
{
  /* If the token is a `{', then we must take special action.  */
  if (cp_lexer_next_token_is_not (parser->lexer, CPP_OPEN_BRACE))
    {
      token_indent_info body_tinfo
	= get_token_indent_info (cp_lexer_peek_token (parser->lexer));
      location_t loc_after_labels = UNKNOWN_LOCATION;

      cp_parser_statement (parser, NULL_TREE, false, if_p, NULL,
			   &loc_after_labels);
      token_indent_info next_tinfo
	= get_token_indent_info (cp_lexer_peek_token (parser->lexer));
      warn_for_misleading_indentation (guard_tinfo, body_tinfo, next_tinfo);

      if (loc_after_labels != UNKNOWN_LOCATION
	  && next_tinfo.type != CPP_SEMICOLON)
	warn_for_multistatement_macros (loc_after_labels, next_tinfo.location,
					guard_tinfo.location,
					guard_tinfo.keyword);
    }
  else
    {
      /* Avoid calling cp_parser_compound_statement, so that we
	 don't create a new scope.  Do everything else by hand.  */
      matching_braces braces;
      braces.require_open (parser);
      /* If the next keyword is `__label__' we have a label declaration.  */
      while (cp_lexer_next_token_is_keyword (parser->lexer, RID_LABEL))
	cp_parser_label_declaration (parser);
      /* Parse an (optional) statement-seq.  */
      cp_parser_statement_seq_opt (parser, NULL_TREE);
      braces.require_close (parser);
    }
}

/* Declarations [gram.dcl.dcl] */

/* Parse an optional declaration-sequence.

   declaration-seq:
     declaration
     declaration-seq declaration  */

static void
cp_parser_declaration_seq_opt (cp_parser* parser)
{
  while (true)
    {
      cp_token *token;

      token = cp_lexer_peek_token (parser->lexer);

      if (token->type == CPP_CLOSE_BRACE
	  || token->type == CPP_EOF
	  || token->type == CPP_PRAGMA_EOL)
	break;

      if (token->type == CPP_SEMICOLON)
	{
	  /* A declaration consisting of a single semicolon is
	     invalid.  Allow it unless we're being pedantic.  */
	  cp_lexer_consume_token (parser->lexer);
	  if (!in_system_header_at (input_location))
	    pedwarn (input_location, OPT_Wpedantic, "extra %<;%>");
	  continue;
	}

      /* If we're entering or exiting a region that's implicitly
	 extern "C", modify the lang context appropriately.  */
      if (!parser->implicit_extern_c && token->implicit_extern_c)
	{
	  push_lang_context (lang_name_c);
	  parser->implicit_extern_c = true;
	}
      else if (parser->implicit_extern_c && !token->implicit_extern_c)
	{
	  pop_lang_context ();
	  parser->implicit_extern_c = false;
	}

      if (token->type == CPP_PRAGMA)
	{
	  /* A top-level declaration can consist solely of a #pragma.
	     A nested declaration cannot, so this is done here and not
	     in cp_parser_declaration.  (A #pragma at block scope is
	     handled in cp_parser_statement.)  */
	  cp_parser_pragma (parser, pragma_external, NULL);
	  continue;
	}

      /* Parse the declaration itself.  */
      cp_parser_declaration (parser);
    }
}

/* Parse a declaration.

   declaration:
     block-declaration
     function-definition
     template-declaration
     explicit-instantiation
     explicit-specialization
     linkage-specification
     namespace-definition

   C++17:
     deduction-guide

   GNU extension:

   declaration:
      __extension__ declaration */

static void
cp_parser_declaration (cp_parser* parser)
{
  cp_token token1;
  cp_token token2;
  int saved_pedantic;
  void *p;
  tree attributes = NULL_TREE;

  /* Check for the `__extension__' keyword.  */
  if (cp_parser_extension_opt (parser, &saved_pedantic))
    {
      /* Parse the qualified declaration.  */
      cp_parser_declaration (parser);
      /* Restore the PEDANTIC flag.  */
      pedantic = saved_pedantic;

      return;
    }

  /* Try to figure out what kind of declaration is present.  */
  token1 = *cp_lexer_peek_token (parser->lexer);

  if (token1.type != CPP_EOF)
    token2 = *cp_lexer_peek_nth_token (parser->lexer, 2);
  else
    {
      token2.type = CPP_EOF;
      token2.keyword = RID_MAX;
    }

  /* Get the high-water mark for the DECLARATOR_OBSTACK.  */
  p = obstack_alloc (&declarator_obstack, 0);

  /* If the next token is `extern' and the following token is a string
     literal, then we have a linkage specification.  */
  if (token1.keyword == RID_EXTERN
      && cp_parser_is_pure_string_literal (&token2))
    cp_parser_linkage_specification (parser);
  /* If the next token is `template', then we have either a template
     declaration, an explicit instantiation, or an explicit
     specialization.  */
  else if (token1.keyword == RID_TEMPLATE)
    {
      /* `template <>' indicates a template specialization.  */
      if (token2.type == CPP_LESS
	  && cp_lexer_peek_nth_token (parser->lexer, 3)->type == CPP_GREATER)
	cp_parser_explicit_specialization (parser);
      /* `template <' indicates a template declaration.  */
      else if (token2.type == CPP_LESS)
	cp_parser_template_declaration (parser, /*member_p=*/false);
      /* Anything else must be an explicit instantiation.  */
      else
	cp_parser_explicit_instantiation (parser);
    }
  /* If the next token is `export', then we have a template
     declaration.  */
  else if (token1.keyword == RID_EXPORT)
    cp_parser_template_declaration (parser, /*member_p=*/false);
  /* If the next token is `extern', 'static' or 'inline' and the one
     after that is `template', we have a GNU extended explicit
     instantiation directive.  */
  else if (cp_parser_allow_gnu_extensions_p (parser)
	   && (token1.keyword == RID_EXTERN
	       || token1.keyword == RID_STATIC
	       || token1.keyword == RID_INLINE)
	   && token2.keyword == RID_TEMPLATE)
    cp_parser_explicit_instantiation (parser);
  /* If the next token is `namespace', check for a named or unnamed
     namespace definition.  */
  else if (token1.keyword == RID_NAMESPACE
	   && (/* A named namespace definition.  */
	       (token2.type == CPP_NAME
		&& (cp_lexer_peek_nth_token (parser->lexer, 3)->type
		    != CPP_EQ))
               || (token2.type == CPP_OPEN_SQUARE
                   && cp_lexer_peek_nth_token (parser->lexer, 3)->type
                   == CPP_OPEN_SQUARE)
	       /* An unnamed namespace definition.  */
	       || token2.type == CPP_OPEN_BRACE
	       || token2.keyword == RID_ATTRIBUTE))
    cp_parser_namespace_definition (parser);
  /* An inline (associated) namespace definition.  */
  else if (token1.keyword == RID_INLINE
	   && token2.keyword == RID_NAMESPACE)
    cp_parser_namespace_definition (parser);
  /* Objective-C++ declaration/definition.  */
  else if (c_dialect_objc () && OBJC_IS_AT_KEYWORD (token1.keyword))
    cp_parser_objc_declaration (parser, NULL_TREE);
  else if (c_dialect_objc ()
	   && token1.keyword == RID_ATTRIBUTE
	   && cp_parser_objc_valid_prefix_attributes (parser, &attributes))
    cp_parser_objc_declaration (parser, attributes);
  /* At this point we may have a template declared by a concept
     introduction.  */
  else if (flag_concepts
	   && cp_parser_template_declaration_after_export (parser,
							   /*member_p=*/false))
    /* We did.  */;
  else
    /* Try to parse a block-declaration, or a function-definition.  */
    cp_parser_block_declaration (parser, /*statement_p=*/false);

  /* Free any declarators allocated.  */
  obstack_free (&declarator_obstack, p);
}

/* Parse a block-declaration.

   block-declaration:
     simple-declaration
     asm-definition
     namespace-alias-definition
     using-declaration
     using-directive

   GNU Extension:

   block-declaration:
     __extension__ block-declaration

   C++0x Extension:

   block-declaration:
     static_assert-declaration

   If STATEMENT_P is TRUE, then this block-declaration is occurring as
   part of a declaration-statement.  */

static void
cp_parser_block_declaration (cp_parser *parser,
			     bool      statement_p)
{
  cp_token *token1;
  int saved_pedantic;

  /* Check for the `__extension__' keyword.  */
  if (cp_parser_extension_opt (parser, &saved_pedantic))
    {
      /* Parse the qualified declaration.  */
      cp_parser_block_declaration (parser, statement_p);
      /* Restore the PEDANTIC flag.  */
      pedantic = saved_pedantic;

      return;
    }

  /* Peek at the next token to figure out which kind of declaration is
     present.  */
  token1 = cp_lexer_peek_token (parser->lexer);

  /* If the next keyword is `asm', we have an asm-definition.  */
  if (token1->keyword == RID_ASM)
    {
      if (statement_p)
	cp_parser_commit_to_tentative_parse (parser);
      cp_parser_asm_definition (parser);
    }
  /* If the next keyword is `namespace', we have a
     namespace-alias-definition.  */
  else if (token1->keyword == RID_NAMESPACE)
    cp_parser_namespace_alias_definition (parser);
  /* If the next keyword is `using', we have a
     using-declaration, a using-directive, or an alias-declaration.  */
  else if (token1->keyword == RID_USING)
    {
      cp_token *token2;

      if (statement_p)
	cp_parser_commit_to_tentative_parse (parser);
      /* If the token after `using' is `namespace', then we have a
	 using-directive.  */
      token2 = cp_lexer_peek_nth_token (parser->lexer, 2);
      if (token2->keyword == RID_NAMESPACE)
	cp_parser_using_directive (parser);
      /* If the second token after 'using' is '=', then we have an
	 alias-declaration.  */
      else if (cxx_dialect >= cxx11
	       && token2->type == CPP_NAME
	       && ((cp_lexer_peek_nth_token (parser->lexer, 3)->type == CPP_EQ)
		   || (cp_nth_tokens_can_be_attribute_p (parser, 3))))
	cp_parser_alias_declaration (parser);
      /* Otherwise, it's a using-declaration.  */
      else
	cp_parser_using_declaration (parser,
				     /*access_declaration_p=*/false);
    }
  /* If the next keyword is `__label__' we have a misplaced label
     declaration.  */
  else if (token1->keyword == RID_LABEL)
    {
      cp_lexer_consume_token (parser->lexer);
      error_at (token1->location, "%<__label__%> not at the beginning of a block");
      cp_parser_skip_to_end_of_statement (parser);
      /* If the next token is now a `;', consume it.  */
      if (cp_lexer_next_token_is (parser->lexer, CPP_SEMICOLON))
	cp_lexer_consume_token (parser->lexer);
    }
  /* If the next token is `static_assert' we have a static assertion.  */
  else if (token1->keyword == RID_STATIC_ASSERT)
    cp_parser_static_assert (parser, /*member_p=*/false);
  /* Anything else must be a simple-declaration.  */
  else
    cp_parser_simple_declaration (parser, !statement_p,
				  /*maybe_range_for_decl*/NULL);
}

/* Parse a simple-declaration.

   simple-declaration:
     decl-specifier-seq [opt] init-declarator-list [opt] ;
     decl-specifier-seq ref-qualifier [opt] [ identifier-list ]
       brace-or-equal-initializer ;

   init-declarator-list:
     init-declarator
     init-declarator-list , init-declarator

   If FUNCTION_DEFINITION_ALLOWED_P is TRUE, then we also recognize a
   function-definition as a simple-declaration.

   If MAYBE_RANGE_FOR_DECL is not NULL, the pointed tree will be set to the
   parsed declaration if it is an uninitialized single declarator not followed
   by a `;', or to error_mark_node otherwise. Either way, the trailing `;',
   if present, will not be consumed.  */

static void
cp_parser_simple_declaration (cp_parser* parser,
			      bool function_definition_allowed_p,
			      tree *maybe_range_for_decl)
{
  cp_decl_specifier_seq decl_specifiers;
  int declares_class_or_enum;
  bool saw_declarator;
  location_t comma_loc = UNKNOWN_LOCATION;
  location_t init_loc = UNKNOWN_LOCATION;

  if (maybe_range_for_decl)
    *maybe_range_for_decl = NULL_TREE;

  /* Defer access checks until we know what is being declared; the
     checks for names appearing in the decl-specifier-seq should be
     done as if we were in the scope of the thing being declared.  */
  push_deferring_access_checks (dk_deferred);

  /* Parse the decl-specifier-seq.  We have to keep track of whether
     or not the decl-specifier-seq declares a named class or
     enumeration type, since that is the only case in which the
     init-declarator-list is allowed to be empty.

     [dcl.dcl]

     In a simple-declaration, the optional init-declarator-list can be
     omitted only when declaring a class or enumeration, that is when
     the decl-specifier-seq contains either a class-specifier, an
     elaborated-type-specifier, or an enum-specifier.  */
  cp_parser_decl_specifier_seq (parser,
				CP_PARSER_FLAGS_OPTIONAL,
				&decl_specifiers,
				&declares_class_or_enum);
  /* We no longer need to defer access checks.  */
  stop_deferring_access_checks ();

  /* In a block scope, a valid declaration must always have a
     decl-specifier-seq.  By not trying to parse declarators, we can
     resolve the declaration/expression ambiguity more quickly.  */
  if (!function_definition_allowed_p
      && !decl_specifiers.any_specifiers_p)
    {
      cp_parser_error (parser, "expected declaration");
      goto done;
    }

  /* If the next two tokens are both identifiers, the code is
     erroneous. The usual cause of this situation is code like:

       T t;

     where "T" should name a type -- but does not.  */
  if (!decl_specifiers.any_type_specifiers_p
      && cp_parser_parse_and_diagnose_invalid_type_name (parser))
    {
      /* If parsing tentatively, we should commit; we really are
	 looking at a declaration.  */
      cp_parser_commit_to_tentative_parse (parser);
      /* Give up.  */
      goto done;
    }

  /* If we have seen at least one decl-specifier, and the next token
     is not a parenthesis, then we must be looking at a declaration.
     (After "int (" we might be looking at a functional cast.)  */
  if (decl_specifiers.any_specifiers_p
      && cp_lexer_next_token_is_not (parser->lexer, CPP_OPEN_PAREN)
      && cp_lexer_next_token_is_not (parser->lexer, CPP_OPEN_BRACE)
      && !cp_parser_error_occurred (parser))
    cp_parser_commit_to_tentative_parse (parser);

  /* Look for C++17 decomposition declaration.  */
  for (size_t n = 1; ; n++)
    if (cp_lexer_nth_token_is (parser->lexer, n, CPP_AND)
	|| cp_lexer_nth_token_is (parser->lexer, n, CPP_AND_AND))
      continue;
    else if (cp_lexer_nth_token_is (parser->lexer, n, CPP_OPEN_SQUARE)
	     && !cp_lexer_nth_token_is (parser->lexer, n + 1, CPP_OPEN_SQUARE)
	     && decl_specifiers.any_specifiers_p)
      {
	tree decl
	  = cp_parser_decomposition_declaration (parser, &decl_specifiers,
						 maybe_range_for_decl,
						 &init_loc);

	/* The next token should be either a `,' or a `;'.  */
	cp_token *token = cp_lexer_peek_token (parser->lexer);
	/* If it's a `;', we are done.  */
	if (token->type == CPP_SEMICOLON || maybe_range_for_decl)
	  goto finish;
	/* Anything else is an error.  */
	else
	  {
	    /* If we have already issued an error message we don't need
	       to issue another one.  */
	    if ((decl != error_mark_node
		 && DECL_INITIAL (decl) != error_mark_node)
		|| cp_parser_uncommitted_to_tentative_parse_p (parser))
	      cp_parser_error (parser, "expected %<,%> or %<;%>");
	    /* Skip tokens until we reach the end of the statement.  */
	    cp_parser_skip_to_end_of_statement (parser);
	    /* If the next token is now a `;', consume it.  */
	    if (cp_lexer_next_token_is (parser->lexer, CPP_SEMICOLON))
	      cp_lexer_consume_token (parser->lexer);
	    goto done;
	  }
      }
    else
      break;

  tree last_type;
  bool auto_specifier_p;
  /* NULL_TREE if both variable and function declaration are allowed,
     error_mark_node if function declaration are not allowed and
     a FUNCTION_DECL that should be diagnosed if it is followed by
     variable declarations.  */
  tree auto_function_declaration;

  last_type = NULL_TREE;
  auto_specifier_p
    = decl_specifiers.type && type_uses_auto (decl_specifiers.type);
  auto_function_declaration = NULL_TREE;

  /* Keep going until we hit the `;' at the end of the simple
     declaration.  */
  saw_declarator = false;
  while (cp_lexer_next_token_is_not (parser->lexer,
				     CPP_SEMICOLON))
    {
      cp_token *token;
      bool function_definition_p;
      tree decl;
      tree auto_result = NULL_TREE;

      if (saw_declarator)
	{
	  /* If we are processing next declarator, comma is expected */
	  token = cp_lexer_peek_token (parser->lexer);
	  gcc_assert (token->type == CPP_COMMA);
	  cp_lexer_consume_token (parser->lexer);
	  if (maybe_range_for_decl)
	    {
	      *maybe_range_for_decl = error_mark_node;
	      if (comma_loc == UNKNOWN_LOCATION)
		comma_loc = token->location;
	    }
	}
      else
	saw_declarator = true;

      /* Parse the init-declarator.  */
      decl = cp_parser_init_declarator (parser, &decl_specifiers,
					/*checks=*/NULL,
					function_definition_allowed_p,
					/*member_p=*/false,
					declares_class_or_enum,
					&function_definition_p,
					maybe_range_for_decl,
					&init_loc,
					&auto_result);
      /* If an error occurred while parsing tentatively, exit quickly.
	 (That usually happens when in the body of a function; each
	 statement is treated as a declaration-statement until proven
	 otherwise.)  */
      if (cp_parser_error_occurred (parser))
	goto done;

      if (auto_specifier_p && cxx_dialect >= cxx14)
	{
	  /* If the init-declarator-list contains more than one
	     init-declarator, they shall all form declarations of
	     variables.  */
	  if (auto_function_declaration == NULL_TREE)
	    auto_function_declaration
	      = TREE_CODE (decl) == FUNCTION_DECL ? decl : error_mark_node;
	  else if (TREE_CODE (decl) == FUNCTION_DECL
		   || auto_function_declaration != error_mark_node)
	    {
	      error_at (decl_specifiers.locations[ds_type_spec],
			"non-variable %qD in declaration with more than one "
			"declarator with placeholder type",
			TREE_CODE (decl) == FUNCTION_DECL
			? decl : auto_function_declaration);
	      auto_function_declaration = error_mark_node;
	    }
	}

      if (auto_result
	  && (!processing_template_decl || !type_uses_auto (auto_result)))
	{
	  if (last_type
	      && last_type != error_mark_node
	      && !same_type_p (auto_result, last_type))
	    {
	      /* If the list of declarators contains more than one declarator,
		 the type of each declared variable is determined as described
		 above. If the type deduced for the template parameter U is not
		 the same in each deduction, the program is ill-formed.  */
	      error_at (decl_specifiers.locations[ds_type_spec],
			"inconsistent deduction for %qT: %qT and then %qT",
			decl_specifiers.type, last_type, auto_result);
	      last_type = error_mark_node;
	    }
	  else
	    last_type = auto_result;
	}

      /* Handle function definitions specially.  */
      if (function_definition_p)
	{
	  /* If the next token is a `,', then we are probably
	     processing something like:

	       void f() {}, *p;

	     which is erroneous.  */
	  if (cp_lexer_next_token_is (parser->lexer, CPP_COMMA))
	    {
	      cp_token *token = cp_lexer_peek_token (parser->lexer);
	      error_at (token->location,
			"mixing"
			" declarations and function-definitions is forbidden");
	    }
	  /* Otherwise, we're done with the list of declarators.  */
	  else
	    {
	      pop_deferring_access_checks ();
	      return;
	    }
	}
      if (maybe_range_for_decl && *maybe_range_for_decl == NULL_TREE)
	*maybe_range_for_decl = decl;
      /* The next token should be either a `,' or a `;'.  */
      token = cp_lexer_peek_token (parser->lexer);
      /* If it's a `,', there are more declarators to come.  */
      if (token->type == CPP_COMMA)
	/* will be consumed next time around */;
      /* If it's a `;', we are done.  */
      else if (token->type == CPP_SEMICOLON)
	break;
      else if (maybe_range_for_decl)
	{
	  if ((declares_class_or_enum & 2) && token->type == CPP_COLON)
	    permerror (decl_specifiers.locations[ds_type_spec],
		       "types may not be defined in a for-range-declaration");
	  break;
	}
      /* Anything else is an error.  */
      else
	{
	  /* If we have already issued an error message we don't need
	     to issue another one.  */
	  if ((decl != error_mark_node
	       && DECL_INITIAL (decl) != error_mark_node)
	      || cp_parser_uncommitted_to_tentative_parse_p (parser))
	    cp_parser_error (parser, "expected %<,%> or %<;%>");
	  /* Skip tokens until we reach the end of the statement.  */
	  cp_parser_skip_to_end_of_statement (parser);
	  /* If the next token is now a `;', consume it.  */
	  if (cp_lexer_next_token_is (parser->lexer, CPP_SEMICOLON))
	    cp_lexer_consume_token (parser->lexer);
	  goto done;
	}
      /* After the first time around, a function-definition is not
	 allowed -- even if it was OK at first.  For example:

	   int i, f() {}

	 is not valid.  */
      function_definition_allowed_p = false;
    }

  /* Issue an error message if no declarators are present, and the
     decl-specifier-seq does not itself declare a class or
     enumeration: [dcl.dcl]/3.  */
  if (!saw_declarator)
    {
      if (cp_parser_declares_only_class_p (parser))
	{
	  if (!declares_class_or_enum
	      && decl_specifiers.type
	      && OVERLOAD_TYPE_P (decl_specifiers.type))
	    /* Ensure an error is issued anyway when finish_decltype_type,
	       called via cp_parser_decl_specifier_seq, returns a class or
	       an enumeration (c++/51786).  */
	    decl_specifiers.type = NULL_TREE;
	  shadow_tag (&decl_specifiers);
	}
      /* Perform any deferred access checks.  */
      perform_deferred_access_checks (tf_warning_or_error);
    }

  /* Consume the `;'.  */
 finish:
  if (!maybe_range_for_decl)
    cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON);
  else if (cp_lexer_next_token_is (parser->lexer, CPP_COLON))
    {
      if (init_loc != UNKNOWN_LOCATION)
	error_at (init_loc, "initializer in range-based %<for%> loop");
      if (comma_loc != UNKNOWN_LOCATION)
	error_at (comma_loc,
		  "multiple declarations in range-based %<for%> loop");
    }

 done:
  pop_deferring_access_checks ();
}

/* Helper of cp_parser_simple_declaration, parse a decomposition declaration.
     decl-specifier-seq ref-qualifier [opt] [ identifier-list ]
       initializer ;  */

static tree
cp_parser_decomposition_declaration (cp_parser *parser,
				     cp_decl_specifier_seq *decl_specifiers,
				     tree *maybe_range_for_decl,
				     location_t *init_loc)
{
  cp_ref_qualifier ref_qual = cp_parser_ref_qualifier_opt (parser);
  location_t loc = cp_lexer_peek_token (parser->lexer)->location;
  cp_parser_require (parser, CPP_OPEN_SQUARE, RT_OPEN_SQUARE);

  /* Parse the identifier-list.  */
  auto_vec<cp_expr, 10> v;
  if (!cp_lexer_next_token_is (parser->lexer, CPP_CLOSE_SQUARE))
    while (true)
      {
	cp_expr e = cp_parser_identifier (parser);
	if (e.get_value () == error_mark_node)
	  break;
	v.safe_push (e);
	if (!cp_lexer_next_token_is (parser->lexer, CPP_COMMA))
	  break;
	cp_lexer_consume_token (parser->lexer);
      }

  location_t end_loc = cp_lexer_peek_token (parser->lexer)->location;
  if (!cp_parser_require (parser, CPP_CLOSE_SQUARE, RT_CLOSE_SQUARE))
    {
      end_loc = UNKNOWN_LOCATION;
      cp_parser_skip_to_closing_parenthesis_1 (parser, true, CPP_CLOSE_SQUARE,
					       false);
      if (cp_lexer_next_token_is (parser->lexer, CPP_CLOSE_SQUARE))
	cp_lexer_consume_token (parser->lexer);
      else
	{
	  cp_parser_skip_to_end_of_statement (parser);
	  return error_mark_node;
	}
    }

  if (cxx_dialect < cxx17)
    pedwarn (loc, 0, "structured bindings only available with "
		     "-std=c++17 or -std=gnu++17");

  tree pushed_scope;
  cp_declarator *declarator = make_declarator (cdk_decomp);
  loc = end_loc == UNKNOWN_LOCATION ? loc : make_location (loc, loc, end_loc);
  declarator->id_loc = loc;
  if (ref_qual != REF_QUAL_NONE)
    declarator = make_reference_declarator (TYPE_UNQUALIFIED, declarator,
					    ref_qual == REF_QUAL_RVALUE,
					    NULL_TREE);
  tree decl = start_decl (declarator, decl_specifiers, SD_INITIALIZED,
			  NULL_TREE, decl_specifiers->attributes,
			  &pushed_scope);
  tree orig_decl = decl;

  unsigned int i;
  cp_expr e;
  cp_decl_specifier_seq decl_specs;
  clear_decl_specs (&decl_specs);
  decl_specs.type = make_auto ();
  tree prev = decl;
  FOR_EACH_VEC_ELT (v, i, e)
    {
      if (i == 0)
	declarator = make_id_declarator (NULL_TREE, e.get_value (), sfk_none);
      else
	declarator->u.id.unqualified_name = e.get_value ();
      declarator->id_loc = e.get_location ();
      tree elt_pushed_scope;
      tree decl2 = start_decl (declarator, &decl_specs, SD_INITIALIZED,
			       NULL_TREE, NULL_TREE, &elt_pushed_scope);
      if (decl2 == error_mark_node)
	decl = error_mark_node;
      else if (decl != error_mark_node && DECL_CHAIN (decl2) != prev)
	{
	  /* Ensure we've diagnosed redeclaration if we aren't creating
	     a new VAR_DECL.  */
	  gcc_assert (errorcount);
	  decl = error_mark_node;
	}
      else
	prev = decl2;
      if (elt_pushed_scope)
	pop_scope (elt_pushed_scope);
    }

  if (v.is_empty ())
    {
      error_at (loc, "empty structured binding declaration");
      decl = error_mark_node;
    }

  if (maybe_range_for_decl == NULL
      || cp_lexer_next_token_is_not (parser->lexer, CPP_COLON))
    {
      bool non_constant_p = false, is_direct_init = false;
      *init_loc = cp_lexer_peek_token (parser->lexer)->location;
      tree initializer = cp_parser_initializer (parser, &is_direct_init,
						&non_constant_p);
      if (initializer == NULL_TREE
	  || (TREE_CODE (initializer) == TREE_LIST
	      && TREE_CHAIN (initializer))
	  || (TREE_CODE (initializer) == CONSTRUCTOR
	      && CONSTRUCTOR_NELTS (initializer) != 1))
	{
	  error_at (loc, "invalid initializer for structured binding "
		    "declaration");
	  initializer = error_mark_node;
	}

      if (decl != error_mark_node)
	{
	  cp_finish_decl (decl, initializer, non_constant_p, NULL_TREE,
			  is_direct_init ? LOOKUP_NORMAL : LOOKUP_IMPLICIT);
	  cp_finish_decomp (decl, prev, v.length ());
	}
    }
  else if (decl != error_mark_node)
    {
      *maybe_range_for_decl = prev;
      /* Ensure DECL_VALUE_EXPR is created for all the decls but
	 the underlying DECL.  */
      cp_finish_decomp (decl, prev, v.length ());
    }

  if (pushed_scope)
    pop_scope (pushed_scope);

  if (decl == error_mark_node && DECL_P (orig_decl))
    {
      if (DECL_NAMESPACE_SCOPE_P (orig_decl))
	SET_DECL_ASSEMBLER_NAME (orig_decl, get_identifier ("<decomp>"));
    }

  return decl;
}

/* Parse a decl-specifier-seq.

   decl-specifier-seq:
     decl-specifier-seq [opt] decl-specifier
     decl-specifier attribute-specifier-seq [opt] (C++11)

   decl-specifier:
     storage-class-specifier
     type-specifier
     function-specifier
     friend
     typedef

   GNU Extension:

   decl-specifier:
     attributes

   Concepts Extension:

   decl-specifier:
     concept

   Set *DECL_SPECS to a representation of the decl-specifier-seq.

   The parser flags FLAGS is used to control type-specifier parsing.

   *DECLARES_CLASS_OR_ENUM is set to the bitwise or of the following
   flags:

     1: one of the decl-specifiers is an elaborated-type-specifier
	(i.e., a type declaration)
     2: one of the decl-specifiers is an enum-specifier or a
	class-specifier (i.e., a type definition)

   */

static void
cp_parser_decl_specifier_seq (cp_parser* parser,
			      cp_parser_flags flags,
			      cp_decl_specifier_seq *decl_specs,
			      int* declares_class_or_enum)
{
  bool constructor_possible_p = !parser->in_declarator_p;
  bool found_decl_spec = false;
  cp_token *start_token = NULL;
  cp_decl_spec ds;

  /* Clear DECL_SPECS.  */
  clear_decl_specs (decl_specs);

  /* Assume no class or enumeration type is declared.  */
  *declares_class_or_enum = 0;

  /* Keep reading specifiers until there are no more to read.  */
  while (true)
    {
      bool constructor_p;
      cp_token *token;
      ds = ds_last;

      /* Peek at the next token.  */
      token = cp_lexer_peek_token (parser->lexer);

      /* Save the first token of the decl spec list for error
         reporting.  */
      if (!start_token)
	start_token = token;
      /* Handle attributes.  */
      if (cp_next_tokens_can_be_attribute_p (parser))