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comparison gcc/testsuite/g++.dg/concepts/dr1430.C @ 111:04ced10e8804

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gcc 7
author kono
date Fri, 27 Oct 2017 22:46:09 +0900
parents
children 84e7813d76e9
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68:561a7518be6b 111:04ced10e8804
1 // PR c++/66092
2 // { dg-options "-std=c++17 -fconcepts" }
3
4 #include <type_traits>
5
6 template <typename T, typename U, typename... Args>
7 requires (sizeof...(Args) == 0)
8 constexpr decltype(auto) check()
9 {
10 return std::integral_constant<bool, __is_same_as(T, U)>();
11 }
12
13 template <typename T, typename U, typename... Args>
14 requires (sizeof...(Args) > 0)
15 constexpr decltype(auto) check()
16 {
17 return std::integral_constant<bool, __is_same_as(T, U)
18 && decltype(check<U, Args...>())::value>();
19 }
20
21 template <typename T, typename U, typename... Args>
22 concept bool Same()
23 {
24 return decltype(check<T, U, Args...>())::value;
25 }
26
27 template <typename T, typename U, typename... Args>
28 concept bool Similar = true;
29
30 template <typename... Args>
31 requires Same<Args...>() // { dg-error "invalid reference" }
32 void foo( Args... args ) {}
33
34 template <typename... Args>
35 requires Similar<Args...> // { dg-error "invalid reference" }
36 void bar( Args... args ) {}
37
38 int main()
39 {
40 foo(1, 2, 3); // { dg-error "cannot call" }
41 bar(1, 2, 3); // { dg-error "cannot call" }
42 }