https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92067
--- Comment #4 from Jason Merrill <jason at gcc dot gnu.org> --- (In reply to Jason Merrill from comment #3) > Hmm? but the standard says that a precondition for std::is_constructible is > the type being complete, and we enforce that with a static_assert (since > PR71579). Why would it be a problem for the builtin to enforce it as well? ...having tried it, one reason not to is that it makes the diagnostic worse: instead of one understandable error from the static_assert, we also get the compiler error, and then another one from trying to access ::value in the class we failed to instantiate. Do other standard library implementations depend on the compiler to diagnose this?
