https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96803
--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-8 branch has been updated by Jonathan Wakely <r...@gcc.gnu.org>: https://gcc.gnu.org/g:6e86f0926f8de014cb0b0218442812e9f3ea8e95 commit r8-10525-g6e86f0926f8de014cb0b0218442812e9f3ea8e95 Author: Jonathan Wakely <jwak...@redhat.com> Date: Tue Sep 22 09:39:33 2020 +0100 libstdc++: Use correct argument type for __use_alloc [PR 96803] The _Tuple_impl constructor for allocator-extended construction from a different tuple type uses the _Tuple_impl's own _Head type in the __use_alloc test. That is incorrect, because the argument tuple could have a different type. Using the wrong type might select the leading-allocator convention when it should use the trailing-allocator convention, or vice versa. This backport includes the value category fix from r11-3348. libstdc++-v3/ChangeLog: PR libstdc++/96803 * include/std/tuple (_Tuple_impl(allocator_arg_t, Alloc, const _Tuple_impl<U...>&)): Replace parameter pack with a type parameter and a pack and pass the first type to __use_alloc. * testsuite/20_util/tuple/cons/96803.cc: New test. (cherry picked from commit 5494edae83ad33c769bd1ebc98f0c492453a6417)
