[Bug c++/54930] New: Add warning switch for "returning reference to temporary" and similar

[Bug c++/54930] New: Add warning switch for "returning reference to temporary" and similar

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54930

             Bug #: 54930
           Summary: Add warning switch for "returning reference to
                    temporary" and similar
    Classification: Unclassified
           Product: gcc
           Version: 4.6.4
            Status: UNCONFIRMED
          Keywords: diagnostic
          Severity: enhancement
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: redi@gcc.gnu.org


The various warnings issued by maybe_warn_about_returning_address_of_local()
are enabled by default, so there is no way to make them (and only them) into
errors.

If they were controlled by a switch such as -Wreturn-local-addr (enabled by
default) then they could be promoted to an error with -Werror=return-local-addr
(or disabled with -Wno-return-local-addr for the foolish.)

[Bug c++/54930] Add warning switch for "returning reference to temporary" and similar

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54930

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-10-15 10:09:01 UTC ---
Created attachment 28448
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28448
add -Wreturn-local-addr switch

This bootstraps, I'll regtest it tonight

[Bug c++/54930] Add warning switch for "returning reference to temporary" and similar

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54930

--- Comment #2 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-10-15 10:11:15 UTC ---
Great. Remember the docs.

[Bug c++/54930] Add warning switch for "returning reference to temporary" and similar

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54930

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-10-15 10:24:14 UTC ---
Yep, and tests :)

[Bug c++/54930] Add warning switch for "returning reference to temporary" and similar

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54930

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2012-10-15
         AssignedTo|unassigned at gcc dot       |redi at gcc dot gnu.org
                   |gnu.org                     |
   Target Milestone|---                         |4.8.0
     Ever Confirmed|0                           |1

[Bug c++/54930] Add warning switch for "returning reference to temporary" and similar

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54930

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-10-18 18:30:40 UTC ---
patch posted for review http://gcc.gnu.org/ml/gcc-patches/2012-10/msg01737.html

[Bug c++/54930] Add warning switch for "returning reference to temporary" and similar

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54930

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-10-29 23:21:42 UTC ---
Author: redi
Date: Mon Oct 29 23:21:35 2012
New Revision: 192968

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=192968
Log:
gcc/c-family:
    PR c++/54930
    * c.opt (Wreturn_local_addr): Define new option.

gcc/c:
    PR c++/54930
    * c-typeck.c (c_finish_return): Use OPT_Wreturn_local_addr.

gcc/cp:
    PR c++/54930
    * typeck.c (maybe_warn_about_returning_address_of_local): Use
    OPT_Wreturn_local_addr.

gcc:
    PR c++/54930
    * doc/invoke.texi (Warning Options): Document -Wno-return-local-addr.

gcc/testsuite:
    PR c++/54930
    * gcc.dg/Wreturn-local-addr.c: New.
    * g++.dg/warn/Wno-return-local-addr.C: New.
    * g++.dg/warn/Wreturn-local-addr.C: New.

Added:
    trunk/gcc/testsuite/g++.dg/warn/Wno-return-local-addr.C
    trunk/gcc/testsuite/g++.dg/warn/Wreturn-local-addr.C
    trunk/gcc/testsuite/gcc.dg/Wreturn-local-addr.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/c-family/ChangeLog
    trunk/gcc/c-family/c.opt
    trunk/gcc/c/ChangeLog
    trunk/gcc/c/c-typeck.c
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/typeck.c
    trunk/gcc/doc/invoke.texi
    trunk/gcc/testsuite/ChangeLog

[Bug c++/54930] Add warning switch for "returning reference to temporary" and similar

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54930

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-10-29 23:22:51 UTC ---
fixed for 4.8.0