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* [Bug c++/115085] New: Variable unqualified-id is falsely treated as rvalue when appearing in braced-init-list @ 2024-05-14 9:38 janschultke at googlemail dot com 2024-05-14 9:41 ` [Bug c++/115085] " janschultke at googlemail dot com ` (4 more replies) 0 siblings, 5 replies; 6+ messages in thread From: janschultke at googlemail dot com @ 2024-05-14 9:38 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115085 Bug ID: 115085 Summary: Variable unqualified-id is falsely treated as rvalue when appearing in braced-init-list Product: gcc Version: 15.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: janschultke at googlemail dot com Target Milestone: --- > int a{}, b = decltype((a)){a}; GCC falsely rejects this (https://godbolt.org/z/a6c4h8Mhv). If you're having trouble reading this, it also rejects: > using T = int&; > int a{}, b = T{a}; Splitting this into multiple lines is also not relevant. The error is: > <source>:3:17: error: cannot bind non-const lvalue reference of type 'T' {aka 'int&'} to an rvalue of type 'int' > 3 | int a{}, b = T{a}; > | ^ There is no apparent reason why should be an rvalue in this context. It is not move-eligible within the initializer of a variable. My guess is something something aggregate initialization doing copy-initialization for each initializer and then getting a prvalue out of that. Dunno, it's quite weird. See https://stackoverflow.com/a/78477064/5740428 for a more in-depth explanation of the relevant wording. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/115085] Variable unqualified-id is falsely treated as rvalue when appearing in braced-init-list 2024-05-14 9:38 [Bug c++/115085] New: Variable unqualified-id is falsely treated as rvalue when appearing in braced-init-list janschultke at googlemail dot com @ 2024-05-14 9:41 ` janschultke at googlemail dot com 2024-05-14 9:50 ` pinskia at gcc dot gnu.org ` (3 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: janschultke at googlemail dot com @ 2024-05-14 9:41 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115085 --- Comment #1 from Jan Schultke <janschultke at googlemail dot com> --- Another user suggested that this is caused by falsely performing temporary materialization. This would make a an xvalue, which would also make the reference binding fail. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/115085] Variable unqualified-id is falsely treated as rvalue when appearing in braced-init-list 2024-05-14 9:38 [Bug c++/115085] New: Variable unqualified-id is falsely treated as rvalue when appearing in braced-init-list janschultke at googlemail dot com 2024-05-14 9:41 ` [Bug c++/115085] " janschultke at googlemail dot com @ 2024-05-14 9:50 ` pinskia at gcc dot gnu.org 2024-05-14 9:58 ` pinskia at gcc dot gnu.org ` (2 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: pinskia at gcc dot gnu.org @ 2024-05-14 9:50 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115085 --- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- I think there is a dup of this bug already filed ... ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/115085] Variable unqualified-id is falsely treated as rvalue when appearing in braced-init-list 2024-05-14 9:38 [Bug c++/115085] New: Variable unqualified-id is falsely treated as rvalue when appearing in braced-init-list janschultke at googlemail dot com 2024-05-14 9:41 ` [Bug c++/115085] " janschultke at googlemail dot com 2024-05-14 9:50 ` pinskia at gcc dot gnu.org @ 2024-05-14 9:58 ` pinskia at gcc dot gnu.org 2024-05-14 10:24 ` janschultke at googlemail dot com 2024-05-14 10:53 ` jlame646 at gmail dot com 4 siblings, 0 replies; 6+ messages in thread From: pinskia at gcc dot gnu.org @ 2024-05-14 9:58 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115085 --- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> --- See https://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1521 also. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/115085] Variable unqualified-id is falsely treated as rvalue when appearing in braced-init-list 2024-05-14 9:38 [Bug c++/115085] New: Variable unqualified-id is falsely treated as rvalue when appearing in braced-init-list janschultke at googlemail dot com ` (2 preceding siblings ...) 2024-05-14 9:58 ` pinskia at gcc dot gnu.org @ 2024-05-14 10:24 ` janschultke at googlemail dot com 2024-05-14 10:53 ` jlame646 at gmail dot com 4 siblings, 0 replies; 6+ messages in thread From: janschultke at googlemail dot com @ 2024-05-14 10:24 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115085 --- Comment #4 from Jan Schultke <janschultke at googlemail dot com> --- https://github.com/cplusplus/CWG/issues/536 ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/115085] Variable unqualified-id is falsely treated as rvalue when appearing in braced-init-list 2024-05-14 9:38 [Bug c++/115085] New: Variable unqualified-id is falsely treated as rvalue when appearing in braced-init-list janschultke at googlemail dot com ` (3 preceding siblings ...) 2024-05-14 10:24 ` janschultke at googlemail dot com @ 2024-05-14 10:53 ` jlame646 at gmail dot com 4 siblings, 0 replies; 6+ messages in thread From: jlame646 at gmail dot com @ 2024-05-14 10:53 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115085 Jason Liam <jlame646 at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jlame646 at gmail dot com --- Comment #5 from Jason Liam <jlame646 at gmail dot com> --- Maybe related bugs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64892 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78209 ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2024-05-14 10:53 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2024-05-14 9:38 [Bug c++/115085] New: Variable unqualified-id is falsely treated as rvalue when appearing in braced-init-list janschultke at googlemail dot com 2024-05-14 9:41 ` [Bug c++/115085] " janschultke at googlemail dot com 2024-05-14 9:50 ` pinskia at gcc dot gnu.org 2024-05-14 9:58 ` pinskia at gcc dot gnu.org 2024-05-14 10:24 ` janschultke at googlemail dot com 2024-05-14 10:53 ` jlame646 at gmail dot com
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