[Bug c++/25980] New: Unexpected name conflict between symbols

[Bug c++/25980] New: Unexpected name conflict between symbols

[dwhorton at gmail dot com]

The following fails to compile, it would appear that symbols from seperate
namespaces are colliding in error:

[dhorton@dev228 tmp]$ cat test2.cpp
namespace ns1 {
    class c {};
    typedef int f;

    static c x;
}

namespace ns2 {
    void f(ns1::c& cc)
    {
    }

    void g()
    {
        f(ns1::x);
    }
}
[dhorton@dev228 tmp]$ g++ -v -save-temps -Wall -c test2.cpp
Reading specs from /usr/local/lib/gcc-lib/i686-pc-linux-gnu/3.3.2/specs
Configured with: /usr/local/share/gcc-3.3.2/configure -march=pentium4 :
(reconfi
gured) /usr/local/share/gcc-3.3.2/configure -march=pentium4 : (reconfigured)
/us
r/local/share/gcc-3.3.2/configure --with-arch=pentium4
Thread model: posix
gcc version 3.3.2
 /usr/local/lib/gcc-lib/i686-pc-linux-gnu/3.3.2/cc1plus -E -D__GNUG__=3 -quiet
-
v -D__GNUC__=3 -D__GNUC_MINOR__=3 -D__GNUC_PATCHLEVEL__=2 -D_GNU_SOURCE
test2.cp
p -Wall test2.ii
ignoring nonexistent directory "NONE/include"
ignoring nonexistent directory "/usr/local/i686-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/include/c++/3.3.2
 /usr/local/include/c++/3.3.2/i686-pc-linux-gnu
 /usr/local/include/c++/3.3.2/backward
 /usr/local/include
 /usr/local/lib/gcc-lib/i686-pc-linux-gnu/3.3.2/include
 /usr/include
End of search list.
 /usr/local/lib/gcc-lib/i686-pc-linux-gnu/3.3.2/cc1plus -fpreprocessed test2.ii
-quiet -dumpbase test2.cpp -auxbase test2 -Wall -version -o test2.s
GNU C++ version 3.3.2 (i686-pc-linux-gnu)
        compiled by GNU C version 3.2.2 20030222 (Red Hat Linux 3.2.2-5).
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
test2.cpp: In function `void ns2::g()':
test2.cpp:3: error: `ns1::f' is not a function,
test2.cpp:10: error:   conflict with `void ns2::f(ns1::c&)'
test2.cpp:15: error:   in call to `f'
[dhorton@dev228 tmp]$
[dhorton@dev228 tmp]$ cat test2.*i*
# 1 "test2.cpp"
# 1 "<built-in>"
# 1 "<command line>"
# 1 "test2.cpp"
namespace ns1 {
    class c {};
    typedef int f;

    static c x;
}

namespace ns2 {
    void f(ns1::c& cc)
    {
    }

    void g()
    {
        f(ns1::x);
    }
}
[dhorton@dev228 tmp]$

I don't see why symbols ns1::f and ns2::f are in conflict here, as when f() in
ns2::g is being resolved ns1::f should not be visible, should it?

If the parameter ns1::x is removed from the signature of ns2::f then there is
no error.  It would appear that the ns1 namespace is being opened up as a
result of the parameter.

The online Comeau C/C++ compiler accepts this particular example.


-- 
           Summary: Unexpected name conflict between symbols
           Product: gcc
           Version: 3.3.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: dwhorton at gmail dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25980

[Bug c++/25980] Unexpected name conflict between symbols

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2006-01-26 18:49 -------
I think you (and EDG) are missing what argument dependent lookup does for this
case.  


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25980

[Bug c++/25980] Unexpected name conflict between symbols

[gdr at cs dot tamu dot edu]

------- Comment #2 from gdr at cs dot tamu dot edu  2006-01-26 18:56 -------
Subject: Re:   New: Unexpected name conflict between symbols

"dwhorton at gmail dot com" <gcc-bugzilla@gcc.gnu.org> writes:

| The following fails to compile, it would appear that symbols from seperate
| namespaces are colliding in error:
| 
| [dhorton@dev228 tmp]$ cat test2.cpp
| namespace ns1 {
|     class c {};
|     typedef int f;
| 
|     static c x;
| }
| 
| namespace ns2 {
|     void f(ns1::c& cc)
|     {
|     }
| 
|     void g()
|     {
|         f(ns1::x);
|     }
| }

[...]

| test2.cpp: In function `void ns2::g()':
| test2.cpp:3: error: `ns1::f' is not a function,
| test2.cpp:10: error:   conflict with `void ns2::f(ns1::c&)'
| test2.cpp:15: error:   in call to `f'
| [dhorton@dev228 tmp]$
| [dhorton@dev228 tmp]$ cat test2.*i*
| # 1 "test2.cpp"
| # 1 "<built-in>"
| # 1 "<command line>"
| # 1 "test2.cpp"
| namespace ns1 {
|     class c {};
|     typedef int f;
| 
|     static c x;
| }
| 
| namespace ns2 {
|     void f(ns1::c& cc)
|     {
|     }
| 
|     void g()
|     {
|         f(ns1::x);
|     }
| }
| [dhorton@dev228 tmp]$
| 
| I don't see why symbols ns1::f and ns2::f are in conflict here, as when f()
in
| ns2::g is being resolved ns1::f should not be visible, should it?

This is a known issue.  Name lookup apply uniformly.  In particular,
ADL finds in this case both function and non-function.
Since we don't have (yet) overload set that can include functions and
non-functions, the program is ill-formed. See Core Issue 218

  http://www.open-std.org/JTC1/SC22/WG21/docs/cwg_active.html#218

Notice that the last note was quite a long time ago -- before C++03
and now we're in the "extensions" timeframe.  There is strong feeling
that name lookup should apply uniformly, and we should also have
overload resolution with function objects included.  
I believe there alreay is a PR for this.  The proper action is to
suspend it until the issue is completely resolved.

-- Gaby


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25980

[Bug c++/25980] Unexpected name conflict between symbols

[dwhorton at gmail dot com]

------- Comment #3 from dwhorton at gmail dot com  2006-01-26 20:27 -------
I see the issue.  I am surprised that ADL causes non-functions from one
namespace to pollute another.  Nonetheless given the present state of the spec
the confict as reported seems to be valid behaviour.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25980

[Bug c++/25980] [DR 218] Unexpected name conflict between symbols

[pinskia at gcc dot gnu dot org]

------- Comment #4 from pinskia at gcc dot gnu dot org  2006-01-28 20:49 -------
Confirmed and then ...


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2006-01-28 20:49:43
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25980

[Bug c++/25980] [DR 218] Unexpected name conflict between symbols

[pinskia at gcc dot gnu dot org]

------- Comment #5 from pinskia at gcc dot gnu dot org  2006-01-28 20:50 -------
Suspending based on the fact the defect report is still opened.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |SUSPENDED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25980

[Bug c++/25980] [DR 218] Unexpected name conflict between symbols

[pinskia at gcc dot gnu dot org]

------- Comment #6 from pinskia at gcc dot gnu dot org  2006-09-19 04:12 -------
(In reply to comment #2)
> I believe there alreay is a PR for this.  The proper action is to
> suspend it until the issue is completely resolved.

Yes PR 17365.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  BugsThisDependsOn|                            |17365


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25980

[Bug c++/25980] [DR 218] Unexpected name conflict between symbols

[pinskia at gcc dot gnu dot org]

------- Comment #7 from pinskia at gcc dot gnu dot org  2006-09-19 04:15 -------
*** Bug 17045 has been marked as a duplicate of this bug. ***


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |gcc-bugzilla at contacts dot
                   |                            |eelis dot net


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25980

[Bug c++/25980] [DR 218] Unexpected name conflict between symbols

[pinskia at gcc dot gnu dot org]

------- Comment #8 from pinskia at gcc dot gnu dot org  2006-09-19 04:16 -------
I am just going to close this as a dup of bug 17365 which is all the same
issues, finding non functions for ADL.

*** This bug has been marked as a duplicate of 17365 ***


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|SUSPENDED                   |RESOLVED
         Resolution|                            |DUPLICATE


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25980