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comparison gcc/testsuite/g++.dg/concepts/req1.C @ 111:04ced10e8804

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gcc 7
author kono
date Fri, 27 Oct 2017 22:46:09 +0900
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children 84e7813d76e9
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68:561a7518be6b 111:04ced10e8804
1 // { dg-do compile }
2 // { dg-options "-std=c++17 -fconcepts" }
3
4 template<typename T>
5 concept bool Class () { return __is_class(T); }
6
7 // Allow a requires-expression with no parms.
8 template<typename T>
9 concept bool C = requires { typename T::type; };
10
11 void f1(auto a) requires Class<decltype(a)>() { }
12 void f2(auto a) requires requires (decltype(a) x) { -x; } { }
13
14 struct S { } s;
15
16 // Allow non-type template parms as constraints.
17 template<bool B> requires B struct S0; // OK
18
19 template<int N> requires N struct S1 { }; // { dg-error "does not have type" }
20 template<int N> requires N == 0 struct S2 { }; // OK
21
22 template<typename T, T X> requires X struct S3 { }; // OK
23 S3<int, 0> s3a; // { dg-error "constraint failure|does not have type" }
24 S3<bool, false> s3b; // { dg-error "constraint failure" }
25
26 int main() {
27 f1(s);
28 f2(0);
29 }