https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106758
--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #3)
> Ah, but it should use the tuple(U1&&...) constructor
Oops, no, the inner tuple uses that one, but the outer tuple uses tuple(const
T&...).
Reduced:
struct tuple
{
tuple(const float&) { }
};
void bar(tuple) {}
template <typename T>
concept test_expression = requires(T value) {
bar({value});
};
template <test_expression T>
void foo(T&&) {}
int main() {
// The following is a valid expression that compiles in GCC and Clang.
bar({12});
// This concept fails in GCC (but not Clang).
foo(12);
}
Clang and EDG accept this, GCC doesn't.
