Mercurial > hg > CbC > CbC_gcc
view gcc/testsuite/g++.dg/template/sfinae13.C @ 131:84e7813d76e9
gcc-8.2
author | mir3636 |
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date | Thu, 25 Oct 2018 07:37:49 +0900 |
parents | 04ced10e8804 |
children |
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// DR 339 // // Test of the use of casts with SFINAE // Boilerplate helpers typedef char yes_type; struct no_type { char data[2]; }; template<typename T> T create_a(); template<typename T> struct type { }; template<bool, typename T = void> struct enable_if { typedef T type; }; template<typename T> struct enable_if<false, T> { }; #define JOIN( X, Y ) DO_JOIN( X, Y ) #define DO_JOIN( X, Y ) DO_JOIN2(X,Y) #define DO_JOIN2( X, Y ) X##Y #define CHECK_CAST(CastKind) \ template<typename T, typename U> \ typename enable_if<(sizeof((JOIN(CastKind,_cast)<U>(create_a<T>())), 0) > 0), \ yes_type>::type \ JOIN(check_,JOIN(CastKind,_cast))(int); \ \ template<typename T, typename U> \ no_type JOIN(check_,JOIN(CastKind,_cast))(...); \ \ template<typename T, typename U> \ struct JOIN(has_,JOIN(CastKind,_cast)) \ { \ static const bool value = \ (sizeof(JOIN(check_,JOIN(CastKind,_cast))<T, U>(0)) == sizeof(yes_type)); \ } template<typename T, typename U> typename enable_if<(sizeof(((U)create_a<T>()), 0) > 0), yes_type>::type check_c_cast(int); template<typename T, typename U> no_type check_c_cast(...); template<typename T, typename U> struct has_c_cast { static const bool value = (sizeof(check_c_cast<T, U>(0)) == sizeof(yes_type)); }; #ifdef __GXX_EXPERIMENTAL_CXX0X__ # define STATIC_ASSERT(Expr) static_assert(Expr, #Expr) #else # define STATIC_ASSERT(Expr) int JOIN(a,__LINE__)[Expr? 1 : -1] #endif CHECK_CAST(static); CHECK_CAST(dynamic); CHECK_CAST(const); CHECK_CAST(reinterpret); struct X { virtual void f(); }; struct Y { operator bool(); }; struct Z : public X { }; STATIC_ASSERT((has_static_cast<int, float>::value)); STATIC_ASSERT((!has_static_cast<X, Y>::value)); STATIC_ASSERT((has_static_cast<Z, X>::value)); STATIC_ASSERT(!(has_dynamic_cast<int, float>::value)); STATIC_ASSERT(!(has_dynamic_cast<X, Y>::value)); STATIC_ASSERT(!(has_dynamic_cast<X, Z>::value)); STATIC_ASSERT(!(has_dynamic_cast<Y, Z>::value)); STATIC_ASSERT((has_dynamic_cast<X*, Z*>::value)); STATIC_ASSERT((has_dynamic_cast<X*, Y*>::value)); STATIC_ASSERT(!(has_dynamic_cast<Y*, Z*>::value)); STATIC_ASSERT(!(has_const_cast<int, float>::value)); STATIC_ASSERT((has_const_cast<const int*, int*>::value)); STATIC_ASSERT((has_const_cast<int*, const int*>::value)); STATIC_ASSERT(!(has_const_cast<const int*, float*>::value)); STATIC_ASSERT((has_reinterpret_cast<int*, float*>::value)); STATIC_ASSERT(!(has_reinterpret_cast<void*, char>::value)); STATIC_ASSERT(!(has_reinterpret_cast<const X, X>::value)); STATIC_ASSERT((has_c_cast<int, float>::value)); STATIC_ASSERT(!(has_c_cast<X, Y>::value)); STATIC_ASSERT(!(has_c_cast<void*, char>::value));