[Bug c++/43824] New: C++0x feature "inline namespace" enabled under -std=c++98; no warnings

[Bug c++/43824] New: C++0x feature "inline namespace" enabled under -std=c++98; no warnings

[bergner at gcc dot gnu dot org]

Inline namespace definitions are a feature proposed under C++0x.  The feature
is not part of the C++98/03 standards.  Code that uses it under -std=c++98
-Wall -Wextra -pedantic should get at least a warning.

bergner@etna:~/gcc/BUGS/> cat t.cpp 
inline namespace A { }
bergner@etna:~/gcc/BUGS/> g++ -std=c++98 -Wall -Wextra -pedantic -c t.cpp 
bergner@etna:~/gcc/BUGS/> echo $?
0

This seems to also be the case for GCC 4.4 and 4.5.


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           Summary: C++0x feature "inline namespace" enabled under -
                    std=c++98; no warnings
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: bergner at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43824

[Bug c++/43824] C++0x feature "inline namespace" enabled under -std=c++98; no warnings

[paolo dot carlini at oracle dot com]

------- Comment #1 from paolo dot carlini at oracle dot com  2010-04-21 00:24 -------
This new feature of C++0x has been pioneered by GCC, used for the
implementation of the special modes of the C++ library (eg, debug-mode, then
parallel-mode, etc). I'm not sure how much we can tighten the warnings without
breaking the long standing usages as implementation detail. If/when we change
something we should also make sure variadic templates are treated consistently.

Adding Jason in CC.


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paolo dot carlini at oracle dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jason at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43824

[Bug c++/43824] C++0x feature "inline namespace" enabled under -std=c++98; no warnings

[redi at gcc dot gnu dot org]

------- Comment #2 from redi at gcc dot gnu dot org  2010-04-21 09:40 -------
Right, this is a GNU extension used to implement the library, which was later
standardised. We also support 'long long' in C++03 mode.
GCC is not intended to be a strict ANSI C++ verification tool, so doesn't
reject all non-portable programs


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43824

[Bug c++/43824] C++0x feature "inline namespace" enabled under -std=c++98; no warnings

[pinskia at gcc dot gnu dot org]

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------- Comment #3 from pinskia at gcc dot gnu dot org  2010-04-21 16:54 -------
(In reply to comment #2)
> Right, this is a GNU extension used to implement the library, which was later
> standardised. We also support 'long long' in C++03 mode.

Yes but with -pedantic we do warn about long long:
t.cc:1:1: warning: ISO C++ 1998 does not support ‘long long’

(and with -pedantic-error we error out).  So the argument using long long as an
example is incorrect.


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pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Keywords|                            |accepts-invalid
   Last reconfirmed|0000-00-00 00:00:00         |2010-04-21 16:54:00
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43824

[Bug c++/43824] C++0x feature "inline namespace" enabled under -std=c++98; no warnings

[redi at gcc dot gnu dot org]

------- Comment #4 from redi at gcc dot gnu dot org  2010-04-21 17:04 -------
good point

then #pragma GCC system_header must disable the warning, so we can use inline
namespaces and variadic templates in the standard library


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43824

[Bug c++/43824] C++0x feature "inline namespace" enabled under -std=c++98; no warnings

[rodrigorivascosta at gmail dot com]

------- Comment #5 from rodrigorivascosta at gmail dot com  2010-07-26 09:59 -------
Created an attachment (id=21313)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=21313&action=view)
Patch to add pedantic warning to inline namespaces in  C++98

I think that this tiny patch should do the trick.

Regards.
-- Rodrigo.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43824

[Bug c++/43824] C++0x feature "inline namespace" enabled under -std=c++98; no warnings

[jason at gcc dot gnu dot org]

------- Comment #6 from jason at gcc dot gnu dot org  2010-09-10 18:29 -------
Subject: Bug 43824

Author: jason
Date: Fri Sep 10 18:28:59 2010
New Revision: 164201

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=164201
Log:
        PR c++/43824
        * error.c (maybe_warn_cpp0x): Add new warning
        CPP0X_INLINE_NAMESPACES.
        * parser.c (cp_parser_namespace_definition): Likewise.
        * cp-tree.h (cpp0x_warn_str): Likewise.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/inline-ns4.C
    trunk/gcc/testsuite/g++.dg/cpp0x/inline-ns5.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/cp-tree.h
    trunk/gcc/cp/error.c
    trunk/gcc/cp/parser.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/g++.dg/cpp0x/inline-ns3.C
    trunk/gcc/testsuite/g++.dg/lookup/strong-using-1.C
    trunk/gcc/testsuite/g++.dg/lookup/strong-using-2.C
    trunk/gcc/testsuite/g++.dg/lookup/strong-using-3.C
    trunk/gcc/testsuite/g++.dg/lookup/strong-using-5.C


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43824