[Bug libstdc++/100667] [11/12 Regression] std::tuple cannot be constructed from A&&, if A not defined (only forward declared)

[cvs-commit at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100667

--- Comment #15 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-12 branch has been updated by Jason Merrill
<ja...@gcc.gnu.org>:

https://gcc.gnu.org/g:ba57a52dbf6a64ba66f72c20064c5c0e8cc9dbbb

commit r12-10470-gba57a52dbf6a64ba66f72c20064c5c0e8cc9dbbb
Author: Jason Merrill <ja...@redhat.com>
Date:   Wed Mar 27 16:14:01 2024 -0400

    c++: __is_constructible ref binding [PR100667]

    The requirement that a type argument be complete is excessive in the case
of
    direct reference binding to the same type, which does not rely on any
    properties of the type.  This is LWG 2939.

            PR c++/100667

    gcc/cp/ChangeLog:

            * semantics.cc (same_type_ref_bind_p): New.
            (finish_trait_expr): Use it.

    gcc/testsuite/ChangeLog:

            * g++.dg/ext/is_constructible8.C: New test.

    (cherry picked from commit 8bb3ef3f6e335e8794590fb712a2661d11d21973)