diff gcc/testsuite/g++.dg/cpp0x/variadic-alias2.C @ 19:2b5abeee2509 default tip

update gcc11
author anatofuz
date Mon, 25 May 2020 07:50:57 +0900
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/cpp0x/variadic-alias2.C	Mon May 25 07:50:57 2020 +0900
@@ -0,0 +1,103 @@
+// PR c++/91966
+// { dg-do compile { target c++11 } }
+
+// Reduced to this include-free example. Further reduction is hard: Either
+// the bug(?) disappears, or the program becomes meaningless.
+
+template<class...>
+struct list {};
+
+struct nil;
+
+////////////////////////////////////////////////////////////////////////////////
+
+template<int n>
+struct number {
+  constexpr /*implicit*/ operator int() const { return n; }
+  using type = number<n>;
+};
+
+using false_ = number<0>;
+using true_ = number<1>;
+
+static_assert(!false_{}, "");
+static_assert(true_{}, "");
+
+template<int... ns> using numbers = list<number<ns>...>;
+
+////////////////////////////////////////////////////////////////////////////////
+
+template<class lhs, class rhs>
+struct less_impl;
+
+template<int lhs, int rhs>
+struct less_impl<number<lhs>, number<rhs>>
+  : number<(lhs < rhs)> {};
+
+template<class lhs, class rhs> using less = typename less_impl<lhs, rhs>::type;
+
+////////////////////////////////////////////////////////////////////////////////
+
+template<class v0, class... vs>
+struct sum_impl {
+  static_assert(sizeof...(vs) == 0, "see specialization");
+  using type = v0;
+};
+
+template<int v0, int v1, class... vs>
+struct sum_impl<number<v0>, number<v1>, vs...>
+  : sum_impl<number<v0 + v1>, vs...> {};
+
+template<class... nums> using sum = typename sum_impl<nums...>::type;
+
+////////////////////////////////////////////////////////////////////////////////
+
+template<class num>
+struct conditional_impl {
+  static_assert(num{}, "see specialization");
+
+  template<class T, class F>
+  using type = T;
+};
+
+template<>
+struct conditional_impl<false_> {
+  template<class T, class F>
+  using type = F;
+};
+
+template<class num, class T, class F>
+using conditional = typename conditional_impl<num>::template type<T, F>;
+
+////////////////////////////////////////////////////////////////////////////////
+
+template<class seq>
+struct min_filter_impl;
+
+template<class... nums>
+struct min_filter_impl<list<nums...>> {
+  template<class num>
+  using count_better_mins = sum<less<nums, num>...>;
+
+  using type = list<conditional<count_better_mins<nums>, nil, nums>...>;
+
+//using debug = list<conditional<count_better_mins<nums>, nil, void>...>;
+
+// error: expansion pattern 'conditional<typename sum_impl<less<nums, nums>...>::type, nil, void>' contains no parameter packs
+
+};
+
+template<class seq> using min_filter = typename min_filter_impl<seq>::type;
+
+////////////////////////////////////////////////////////////////////////////////
+
+void test_min_filter() {
+  using computed = min_filter<numbers<2, 7, 2>>;
+  using expected = list<number<2>, nil, number<2>>;
+  (void)(computed{} = expected{});// compiles for identical types
+
+// error: no match for 'operator=' (operand types are 'computed' {aka 'list<number<2>, number<7>, number<2> >'} and 'expected' {aka 'list<number<2>, nil, number<2> >'})
+
+}
+
+int main() {}