| // { dg-do compile { target c++17_only } } |
| // { dg-options "-fconcepts" } |
| |
| template<typename T> |
| concept bool C1 = __is_same_as(T, int); |
| |
| template<int N> |
| concept bool C2 = N == 0; |
| |
| template<template<typename> class X> |
| concept bool C3 = false; |
| |
| template<typename> struct Foo; |
| |
| // Instantiation of default arguments happens at the point of |
| // instantiation for the class. |
| |
| template<C1 T = char> struct S1 { }; |
| template<C2 N = 1> struct S2 { }; |
| template<C3 X = Foo> struct S3 { }; |
| |
| S1<> s1; // { dg-error "constraint failure|invalid type" } |
| S2<> s2; // { dg-error "constraint failure|invalid type" } |
| S3<> s3; // { dg-error "constraint failure|invalid type" } |
