[Bug libstdc++/100630] Unexpected implicit conversion from volatile bool& to std::filesystem::path in gcc <= 10
cvs-commit at gcc dot gnu.org
gcc-bugzilla@gcc.gnu.org
Mon May 17 20:52:27 GMT 2021
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100630
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Jonathan Wakely
<redi@gcc.gnu.org>:
https://gcc.gnu.org/g:f8d2cef5c544dd0196ec5a6f479fbf96d2214d76
commit r11-8425-gf8d2cef5c544dd0196ec5a6f479fbf96d2214d76
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Mon May 17 11:54:06 2021 +0100
libstdc++: Fix filesystem::path constraints for volatile [PR 100630]
The constraint check for filesystem::path construction uses
decltype(__is_path_src(declval<Source>())) which mean it considers
conversion from an rvalue. When Source is a volatile-qualified type
it cannot use is_path_src(const Unknown&) because a const lvalue
reference can only bind to a non-volatile rvalue.
Since the relevant path members all have a const Source& parameter,
the constraint should be defined in terms of declval<const Source&>(),
not declval<Source>(). This avoids the problem of volatile-qualified
rvalues, because we no longer use an rvalue at all.
libstdc++-v3/ChangeLog:
PR libstdc++/100630
* include/experimental/bits/fs_path.h (__is_constructible_from):
Test construction from a const lvalue, not an rvalue.
* testsuite/27_io/filesystem/path/construct/100630.cc: New test.
* testsuite/experimental/filesystem/path/construct/100630.cc:
New test.
(cherry picked from commit 45aa7a447652e8541cc381d7ab128544f81ed857)
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