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// PR c++/109752 // { dg-do compile { target c++20 } } template<class T> concept C = requires { sizeof(T); } && T::value; // { dg-error "changed from" } struct A; static_assert(!C<A>); struct A { static constexpr bool value = false; }; static_assert(C<A>); // { dg-error "assert" }