1 // { dg-options "-std=c++17 -fconcepts" }
4 concept bool C() { return __is_class(T); }
7 concept bool D() { return C<T>() and __is_empty(T); }
9 template<template<typename Q> requires C<Q>() class X>
12 template<typename A> requires true struct T0 { };
13 template<typename A> requires D<A>() struct T1 { };
15 S<T0> x3; // { dg-error "constraint mismatch|invalid type" }
16 S<T1> x4; // { dg-error "constraint mismatch|invalid type" }