[Bug libstdc++/100630] Unexpected implicit conversion from volatile bool& to std::filesystem::path in gcc <= 10
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100630 Jonathan Wakely changed: What|Removed |Added Status|NEW |RESOLVED Resolution|--- |FIXED --- Comment #8 from Jonathan Wakely --- Fixed for 9.5, 10.4 and 11.2
[Bug libstdc++/100630] Unexpected implicit conversion from volatile bool& to std::filesystem::path in gcc <= 10
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100630 --- Comment #7 from CVS Commits --- The releases/gcc-9 branch has been updated by Jonathan Wakely : https://gcc.gnu.org/g:3c805829c9023da48db6d636221fd79612dff7ea commit r9-9593-g3c805829c9023da48db6d636221fd79612dff7ea Author: Jonathan Wakely 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())) 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(), not declval(). This avoids the problem of volatile-qualified rvalues, because we no longer use an rvalue at all. libstdc++-v3/ChangeLog: PR libstdc++/100630 * include/bits/fs_path.h (__is_constructible_from): Test construction from a const lvalue, not an rvalue. * include/experimental/bits/fs_path.h (__is_constructible_from): Likewise. * testsuite/27_io/filesystem/path/construct/100630.cc: New test. * testsuite/experimental/filesystem/path/construct/100630.cc: New test. (cherry picked from commit 4cd69a5a0dd31bc6fdef1bbabc8d6d1416014ea1)
[Bug libstdc++/100630] Unexpected implicit conversion from volatile bool& to std::filesystem::path in gcc <= 10
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100630 Jonathan Wakely changed: What|Removed |Added Target Milestone|--- |9.5 --- Comment #6 from Jonathan Wakely --- It's too late for 9.4 but I plan to backport it for 9.5
[Bug libstdc++/100630] Unexpected implicit conversion from volatile bool& to std::filesystem::path in gcc <= 10
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100630 --- Comment #5 from Romain Geissler --- Hi, Thanks for providing a fix that quickly ! I backported it in my own copy of gcc 8 and 9 and it fixed my issue on these branches as well. Cheers, Romain
[Bug libstdc++/100630] Unexpected implicit conversion from volatile bool& to std::filesystem::path in gcc <= 10
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100630 --- Comment #4 from CVS Commits --- The releases/gcc-11 branch has been updated by Jonathan Wakely : https://gcc.gnu.org/g:f8d2cef5c544dd0196ec5a6f479fbf96d2214d76 commit r11-8425-gf8d2cef5c544dd0196ec5a6f479fbf96d2214d76 Author: Jonathan Wakely 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())) 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(), not declval(). 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)
[Bug libstdc++/100630] Unexpected implicit conversion from volatile bool& to std::filesystem::path in gcc <= 10
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100630 --- Comment #3 from CVS Commits --- The master branch has been updated by Jonathan Wakely : https://gcc.gnu.org/g:45aa7a447652e8541cc381d7ab128544f81ed857 commit r12-845-g45aa7a447652e8541cc381d7ab128544f81ed857 Author: Jonathan Wakely 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())) 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(), not declval(). 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.
[Bug libstdc++/100630] Unexpected implicit conversion from volatile bool& to std::filesystem::path in gcc <= 10
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100630 --- Comment #2 from CVS Commits --- The releases/gcc-10 branch has been updated by Jonathan Wakely : https://gcc.gnu.org/g:4cd69a5a0dd31bc6fdef1bbabc8d6d1416014ea1 commit r10-9831-g4cd69a5a0dd31bc6fdef1bbabc8d6d1416014ea1 Author: Jonathan Wakely 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())) 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(), not declval(). This avoids the problem of volatile-qualified rvalues, because we no longer use an rvalue at all. libstdc++-v3/ChangeLog: PR libstdc++/100630 * include/bits/fs_path.h (__is_constructible_from): Test construction from a const lvalue, not an rvalue. * include/experimental/bits/fs_path.h (__is_constructible_from): Likewise. * testsuite/27_io/filesystem/path/construct/100630.cc: New test. * testsuite/experimental/filesystem/path/construct/100630.cc: New test.
[Bug libstdc++/100630] Unexpected implicit conversion from volatile bool& to std::filesystem::path in gcc <= 10
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100630
Jonathan Wakely changed:
What|Removed |Added
Last reconfirmed||2021-05-17
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
--- Comment #1 from Jonathan Wakely ---
(In reply to Romain Geissler from comment #0)
> Hi,
>
> I came across this issue today (which I think is unexpected) with gcc 8, 9
> and 10. It seems that the following code triggers some implicit conversion
> from volatile bool& to std::filesystem::path while this was definitely not
> the intention:
It's not triggering such a conversion, it's checking if such a conversion is
viable as part of overload resolution. But then that instantiates something
that is ill-formed and fails with an error outside the immediate context.
I think the right fix for the branches is:
--- a/libstdc++-v3/include/bits/fs_path.h
+++ b/libstdc++-v3/include/bits/fs_path.h
@@ -116,7 +116,7 @@ namespace __detail
template
struct __constructible_from<_Source, void>
-: decltype(__is_path_src(std::declval<_Source>(), 0))
+: decltype(__is_path_src(std::declval(), 0))
{ };
template
