We accept this testcase after r12-6773 ("CTAD inside alias template").
PR c++/103631 gcc/testsuite/ChangeLog: * g++.dg/cpp2a/nontype-class51.C: New test. --- gcc/testsuite/g++.dg/cpp2a/nontype-class51.C | 26 ++++++++++++++++++++ 1 file changed, 26 insertions(+) create mode 100644 gcc/testsuite/g++.dg/cpp2a/nontype-class51.C diff --git a/gcc/testsuite/g++.dg/cpp2a/nontype-class51.C b/gcc/testsuite/g++.dg/cpp2a/nontype-class51.C new file mode 100644 index 00000000000..1501aa1c426 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/nontype-class51.C @@ -0,0 +1,26 @@ +// PR c++/103631 +// { dg-do compile { target c++20 } } + +template<class Target, template<auto> class T> +constexpr bool is_specialize_value_v = false; + +template<template<auto> class T, auto Ts> +constexpr bool is_specialize_value_v<T<Ts>, T> = true; + +template<class Target, template<auto> class T> +concept specialize_value = is_specialize_value_v<Target, T>; + +template<int> struct Test { }; + +template<Test> +struct A { + template<class T> void f(T) requires specialize_value<T, A>; +}; + +int main() { + A<Test<0>{}> a0; + A<Test<1>{}> a1; + a0.f(a0); + a0.f(a1); + a0.f(0); // { dg-error "no match" } +} -- 2.35.0.rc1