https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108952
Bug ID: 108952
Summary: Regression in uses_allocator_construction_args for
pair of rvalue references
Product: gcc
Version: 12.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: christian.mazakas at gmail dot com
Target Milestone: ---
Consider the following example as demonstrated on Compiler Explorer:
https://godbolt.org/z/jhxxK9hT3
The C++20 version of uses_allocator_construction_args seems to inappropriately
forward the pair's data members and when they happen to be rvalue references,
they decay to an lvalue reference which breaks constructibility tests.
This same code will pass for previous standards versions.
I'm not sure about the range of compilers affected by this but it seems to
follow wherever C++20 support is enabled.
