[Bug c++/29028] No warning about unused names introduced with using declarations

[Bug c++/29028] No warning about unused names introduced with using declarations

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29028

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|gcc-bugs at gcc dot gnu.org |dodji at gcc dot gnu.org

--- Comment #2 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-11-06 23:27:11 UTC ---
Adding Dodji in CC, the issue reminds me so much the "unused typedef"
warning...

[Bug c++/29028] No warning about unused names introduced with using declarations

[dodji at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29028

Dodji Seketeli <dodji at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
         AssignedTo|unassigned at gcc dot       |dodji at gcc dot gnu.org
                   |gnu.org                     |

[Bug c++/29028] No warning about unused names introduced with using declarations

[dodji at seketeli dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29028

--- Comment #3 from dodji at seketeli dot org <dodji at seketeli dot org> 2012-09-21 13:02:15 UTC ---
A candidate patch has been sent to
http://gcc.gnu.org/ml/gcc-patches/2012-09/msg01540.html.

[Bug c++/29028] No warning about unused names introduced with using declarations

[dodji at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29028

--- Comment #4 from Dodji Seketeli <dodji at gcc dot gnu.org> 2012-09-28 12:51:42 UTC ---
Author: dodji
Date: Fri Sep 28 12:51:30 2012
New Revision: 191829

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=191829
Log:
PR c++/29028 - Missed unused warning on using declaration

In the example of the patch, g++ fails to warn that the variable N::i
(introduced via a using declaration) is unused.

This is because as we want to emit the warning in poplevel, when we
walk the local bindings returned by getdecls, we forget that a
VAR_DECL introduced by a using declaration is represented by a
TREE_LIST which TREE_VALUE is the VAR_DECL, and we wrongly look for a
bare VAR_DECL.

Fixed thus and tested on x86_64-unknown-linux-gnu against trunk.

gcc/cp/

    * decl.c (poplevel<warn_unused*>): Do not forget that some local
    bindings are represented by a TREE_LIST.

gcc/testsuite/

    * g++.dg/warn/Wunused-var-18.C: New test.

Added:
    trunk/gcc/testsuite/g++.dg/warn/Wunused-var-18.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/decl.c
    trunk/gcc/testsuite/ChangeLog

[Bug c++/29028] No warning about unused names introduced with using declarations

[dodji at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29028

Dodji Seketeli <dodji at gcc dot gnu.org> changed:

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

--- Comment #5 from Dodji Seketeli <dodji at gcc dot gnu.org> 2012-09-28 13:01:56 UTC ---
Fixed in trunk (4.8)

[Bug c++/29028] No warning about unused names introduced with using declarations

[pinskia at gcc dot gnu dot org]

-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|minor                       |enhancement


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29028

[Bug c++/29028] No warning about unused names introduced with using declarations

[bangerth at dealii dot org]

------- Comment #1 from bangerth at dealii dot org  2006-09-12 03:58 -------
At first I thought that the warning is not useful since the variable may
in fact not be unused at all -- the using declaration simply makes the
name available in the present scope.

However, then I realized that this also holds here:
----------------
void f()
{
  extern int i;
}
----------------
For this code, we warn, though:

g/x> /home/bangerth/bin/gcc-4.2-pre/bin/c++ -Wunused -c x.cc
x.cc: In function ‘void f()’:
x.cc:3: warning: unused variable ‘i’

So for the sake of consistency, we should probably do the same in both
situations, whatever "the same" is here.

W.


-- 

bangerth at dealii dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2006-09-12 03:58:07
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29028