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* [Bug c++/96103] New: Unclear diagnostic for a function return with "decltype(auto)" @ 2020-07-07 17:41 haoxintu at gmail dot com 2020-07-07 20:19 ` [Bug c++/96103] " mpolacek at gcc dot gnu.org ` (5 more replies) 0 siblings, 6 replies; 7+ messages in thread From: haoxintu at gmail dot com @ 2020-07-07 17:41 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96103 Bug ID: 96103 Summary: Unclear diagnostic for a function return with "decltype(auto)" Product: gcc Version: 11.0 Status: UNCONFIRMED Keywords: diagnostic Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: haoxintu at gmail dot com Target Milestone: --- Hi, all. This code, "decltype(auto)" in return type is a c++14 extension and I guess GCC might diagnose this better. $cat test.cc decltype(auto) foo () {} $g++ -c -std=c++11 test.cc test.cc:1:10: error: expected primary-expression before ‘auto’ 1 | decltype(auto) foo () {} | ^~~~ test.cc: In function ‘int foo()’: test.cc:1:24: warning: no return statement in function returning non-void [-Wreturn-type] 1 | decltype(auto) foo () {} | ^ $g++ -c -std=c++14 test.cc //emits nothing While in Clang: $clang++ -c -std=c++11 test.cc test.cc:1:10: warning: 'decltype(auto)' type specifier is a C++14 extension [-Wc++14-extensions] decltype(auto) foo () {} ^ test.cc:1:1: error: deduced return types are a C++14 extension decltype(auto) foo () {} ^ 1 warning and 1 error generated. I guess users can not fix the code according to the errors emitted until they realized this is a C++14 extension. Should GCC recognizes the C++14 extension first when parsing this code and then emits the appropriate diagnostic information? Thanks, Haoxin ^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/96103] Unclear diagnostic for a function return with "decltype(auto)" 2020-07-07 17:41 [Bug c++/96103] New: Unclear diagnostic for a function return with "decltype(auto)" haoxintu at gmail dot com @ 2020-07-07 20:19 ` mpolacek at gcc dot gnu.org 2020-07-07 21:13 ` mpolacek at gcc dot gnu.org ` (4 subsequent siblings) 5 siblings, 0 replies; 7+ messages in thread From: mpolacek at gcc dot gnu.org @ 2020-07-07 20:19 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96103 Marek Polacek <mpolacek at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|0 |1 Status|UNCONFIRMED |NEW Last reconfirmed| |2020-07-07 CC| |mpolacek at gcc dot gnu.org --- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> --- Confirmed, we should tweak cp_parser_decltype to give a better error. ^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/96103] Unclear diagnostic for a function return with "decltype(auto)" 2020-07-07 17:41 [Bug c++/96103] New: Unclear diagnostic for a function return with "decltype(auto)" haoxintu at gmail dot com 2020-07-07 20:19 ` [Bug c++/96103] " mpolacek at gcc dot gnu.org @ 2020-07-07 21:13 ` mpolacek at gcc dot gnu.org 2020-07-08 13:33 ` cvs-commit at gcc dot gnu.org ` (3 subsequent siblings) 5 siblings, 0 replies; 7+ messages in thread From: mpolacek at gcc dot gnu.org @ 2020-07-07 21:13 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96103 Marek Polacek <mpolacek at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |ASSIGNED Assignee|unassigned at gcc dot gnu.org |mpolacek at gcc dot gnu.org ^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/96103] Unclear diagnostic for a function return with "decltype(auto)" 2020-07-07 17:41 [Bug c++/96103] New: Unclear diagnostic for a function return with "decltype(auto)" haoxintu at gmail dot com 2020-07-07 20:19 ` [Bug c++/96103] " mpolacek at gcc dot gnu.org 2020-07-07 21:13 ` mpolacek at gcc dot gnu.org @ 2020-07-08 13:33 ` cvs-commit at gcc dot gnu.org 2020-07-08 13:34 ` mpolacek at gcc dot gnu.org ` (2 subsequent siblings) 5 siblings, 0 replies; 7+ messages in thread From: cvs-commit at gcc dot gnu.org @ 2020-07-08 13:33 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96103 --- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Marek Polacek <mpolacek@gcc.gnu.org>: https://gcc.gnu.org/g:a51de1af063b0a9233762dcd6ecf2ea0bdf4cdff commit r11-1913-ga51de1af063b0a9233762dcd6ecf2ea0bdf4cdff Author: Marek Polacek <polacek@redhat.com> Date: Tue Jul 7 17:09:42 2020 -0400 c++: Better diagnostic for decltype(auto) in C++11 [PR96103] If you try to use decltype(auto) in C++11, we emit obscure error: expected primary-expression before 'auto' giving the user no hint as to what's wrong. This patch improves that diagnostic. Since we've been giving an error, I'm also using error(). gcc/cp/ChangeLog: PR c++/96103 * parser.c (cp_parser_decltype): Print error about using decltype(auto) in C++11. Check that the token following "auto" is ")". gcc/testsuite/ChangeLog: PR c++/96103 * g++.dg/cpp0x/decltype77.C: New test. ^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/96103] Unclear diagnostic for a function return with "decltype(auto)" 2020-07-07 17:41 [Bug c++/96103] New: Unclear diagnostic for a function return with "decltype(auto)" haoxintu at gmail dot com ` (2 preceding siblings ...) 2020-07-08 13:33 ` cvs-commit at gcc dot gnu.org @ 2020-07-08 13:34 ` mpolacek at gcc dot gnu.org 2021-09-07 17:07 ` pinskia at gcc dot gnu.org 2021-09-07 17:07 ` pinskia at gcc dot gnu.org 5 siblings, 0 replies; 7+ messages in thread From: mpolacek at gcc dot gnu.org @ 2020-07-08 13:34 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96103 Marek Polacek <mpolacek at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|ASSIGNED |RESOLVED Resolution|--- |FIXED --- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> --- Fixed. ^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/96103] Unclear diagnostic for a function return with "decltype(auto)" 2020-07-07 17:41 [Bug c++/96103] New: Unclear diagnostic for a function return with "decltype(auto)" haoxintu at gmail dot com ` (3 preceding siblings ...) 2020-07-08 13:34 ` mpolacek at gcc dot gnu.org @ 2021-09-07 17:07 ` pinskia at gcc dot gnu.org 2021-09-07 17:07 ` pinskia at gcc dot gnu.org 5 siblings, 0 replies; 7+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-09-07 17:07 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96103 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Target Milestone|--- |11.0 ^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/96103] Unclear diagnostic for a function return with "decltype(auto)" 2020-07-07 17:41 [Bug c++/96103] New: Unclear diagnostic for a function return with "decltype(auto)" haoxintu at gmail dot com ` (4 preceding siblings ...) 2021-09-07 17:07 ` pinskia at gcc dot gnu.org @ 2021-09-07 17:07 ` pinskia at gcc dot gnu.org 5 siblings, 0 replies; 7+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-09-07 17:07 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96103 --- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> --- *** Bug 95658 has been marked as a duplicate of this bug. *** ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2021-09-07 17:07 UTC | newest] Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-07-07 17:41 [Bug c++/96103] New: Unclear diagnostic for a function return with "decltype(auto)" haoxintu at gmail dot com 2020-07-07 20:19 ` [Bug c++/96103] " mpolacek at gcc dot gnu.org 2020-07-07 21:13 ` mpolacek at gcc dot gnu.org 2020-07-08 13:33 ` cvs-commit at gcc dot gnu.org 2020-07-08 13:34 ` mpolacek at gcc dot gnu.org 2021-09-07 17:07 ` pinskia at gcc dot gnu.org 2021-09-07 17:07 ` pinskia at gcc dot gnu.org
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