[Bug c++/31187] New: [4.2 regression] extern declaration of variable in anonymous namespace prevents use of its address as template argument

[Bug c++/31187] New: [4.2 regression] extern declaration of variable in anonymous namespace prevents use of its address as template argument

[zak at transversal dot com]

The following code, which compiles fine on gcc 4.1.2 and I believe is valid,
fails on an up-to-date checkout from the 4.2 branch:

--------------------------------------
class foo { };

namespace
{
        extern foo foo1;
        foo foo1;
}

template< foo * >
class bar { };

bar< &foo1 > bar1;
---------------------------------------

giving the error:

test.cc:12: error: '&<unnamed>::foo1' is not a valid template argument of type
'foo*' because '<unnamed>::foo1' does not have external linkage
test.cc:12: error: invalid type in declaration before ';' token


... which I would only expect if "foo1" were declared "static".


If I remove the line with the "extern" declaration, the code compiles again on
4.2.


-- 
           Summary: [4.2 regression] extern declaration of variable in
                    anonymous namespace prevents use of its address as
                    template argument
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: zak at transversal dot com
 GCC build triplet: x86_64-pc-linux-gnu
  GCC host triplet: x86_64-pc-linux-gnu
GCC target triplet: x86_64-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31187

[Bug c++/31187] [4.2/4.3 regression] extern declaration of variable in anonymous namespace prevents use of its address as template argument

[pinskia at gcc dot gnu dot org]

-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pinskia at gcc dot gnu dot
                   |                            |org, mmitchel at gcc dot gnu
                   |                            |dot org
           Severity|normal                      |blocker
  GCC build triplet|x86_64-pc-linux-gnu         |
   GCC host triplet|x86_64-pc-linux-gnu         |
            Summary|[4.2 regression] extern     |[4.2/4.3 regression] extern
                   |declaration of variable in  |declaration of variable in
                   |anonymous namespace prevents|anonymous namespace prevents
                   |use of its address as       |use of its address as
                   |template argument           |template argument
   Target Milestone|---                         |4.2.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31187

[Bug c++/31187] [4.2/4.3 regression] extern declaration of variable in anonymous namespace prevents use of its address as template argument

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2007-03-15 16:07 -------
Confirmed.


-- 

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         |2007-03-15 16:07:38
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31187

[Bug c++/31187] [4.2/4.3 regression] extern declaration of variable in anonymous namespace prevents use of its address as template argument

[gdr at cs dot tamu dot edu]

------- Comment #2 from gdr at cs dot tamu dot edu  2007-03-16 15:15 -------
Subject: Re:   New: [4.2 regression] extern declaration of variable in
anonymous namespace prevents use of its address as template argument

"zak at transversal dot com" <gcc-bugzilla@gcc.gnu.org> writes:

| The following code, which compiles fine on gcc 4.1.2 and I believe is valid,
| fails on an up-to-date checkout from the 4.2 branch:
| 
| --------------------------------------
| class foo { };
| 
| namespace
| {
|         extern foo foo1;
|         foo foo1;
| }
| 
| template< foo * >
| class bar { };
| 
| bar< &foo1 > bar1;
| ---------------------------------------
| 
| giving the error:
| 
| test.cc:12: error: '&<unnamed>::foo1' is not a valid template argument of
type
| 'foo*' because '<unnamed>::foo1' does not have external linkage
| test.cc:12: error: invalid type in declaration before ';' token
| 
| 
| ... which I would only expect if "foo1" were declared "static".

Yes, this is a bug in the compiler.  I suspect it was introduced when
the the back was told to treat declarations at unnamed namespaces
ast static.  That of course is an optimization and should be appear at
the front-end.

-- gaby


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31187

Re: [Bug c++/31187] New: [4.2 regression] extern declaration of variable in anonymous namespace prevents use of its address as template argument

[Gabriel Dos Reis]

"zak at transversal dot com" <gcc-bugzilla@gcc.gnu.org> writes:

| The following code, which compiles fine on gcc 4.1.2 and I believe is valid,
| fails on an up-to-date checkout from the 4.2 branch:
| 
| --------------------------------------
| class foo { };
| 
| namespace
| {
|         extern foo foo1;
|         foo foo1;
| }
| 
| template< foo * >
| class bar { };
| 
| bar< &foo1 > bar1;
| ---------------------------------------
| 
| giving the error:
| 
| test.cc:12: error: '&<unnamed>::foo1' is not a valid template argument of type
| 'foo*' because '<unnamed>::foo1' does not have external linkage
| test.cc:12: error: invalid type in declaration before ';' token
| 
| 
| ... which I would only expect if "foo1" were declared "static".

Yes, this is a bug in the compiler.  I suspect it was introduced when
the the back was told to treat declarations at unnamed namespaces
ast static.  That of course is an optimization and should be appear at
the front-end.

-- gaby

[Bug c++/31187] [4.2/4.3 regression] extern declaration of variable in anonymous namespace prevents use of its address as template argument

[mmitchel at gcc dot gnu dot org]

-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31187

[Bug c++/31187] [4.2/4.3 regression] extern declaration of variable in anonymous namespace prevents use of its address as template argument

[mmitchel at gcc dot gnu dot org]

------- Comment #3 from mmitchel at gcc dot gnu dot org  2007-03-22 23:34 -------
Jason -- 

This appears to be fallout from your patch for PR c++/28407 and/or c++/28409. 
Do you have time to take a look?

Thanks,

-- Mark


-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jason at redhat dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31187

[Bug c++/31187] [4.2/4.3 regression] extern declaration of variable in anonymous namespace prevents use of its address as template argument

[bangerth at dealii dot org]

------- Comment #4 from bangerth at dealii dot org  2007-03-23 02:37 -------
Without wanting to be a distractor, but can variables of a type that
was declared in an anonymous namespace really have external linkage?
Think of the type being declared in a header file and one .cc file
has the variable declaration/definition and another one an extern
declaration for that variable. Do they refer to the same variable? I
don't think so -- they have the same name, but distinct types, so we
have an ODR violation.

IMHO, variables with a type that comes from an anonymous namespace
can but have internal linkage.
W.


-- 

bangerth at dealii dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bangerth at dealii dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31187

[Bug c++/31187] [4.2/4.3 regression] extern declaration of variable in anonymous namespace prevents use of its address as template argument

[mark at codesourcery dot com]

------- Comment #5 from mark at codesourcery dot com  2007-03-23 02:44 -------
Subject: Re:  [4.2/4.3 regression] extern declaration of variable
 in anonymous namespace prevents use of its address as template argument

bangerth at dealii dot org wrote:
> ------- Comment #4 from bangerth at dealii dot org  2007-03-23 02:37 -------
> Without wanting to be a distractor, but can variables of a type that
> was declared in an anonymous namespace really have external linkage?

That's not the case here; the class is in the global namespace.  Only
the variable is in the anonymous namespace, and entities in anonymous
namespaces do have external linkage.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31187

[Bug c++/31187] [4.2/4.3 regression] extern declaration of variable in anonymous namespace prevents use of its address as template argument

[bangerth at dealii dot org]

------- Comment #6 from bangerth at dealii dot org  2007-03-23 03:03 -------
(In reply to comment #5)
> That's not the case here; the class is in the global namespace.

Oh, bummer, of course...


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31187

[Bug c++/31187] [4.2/4.3 regression] extern declaration of variable in anonymous namespace prevents use of its address as template argument

[jason at gcc dot gnu dot org]

-- 

jason at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |jason at gcc dot gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2007-03-15 16:07:38         |2007-03-27 03:37:29
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31187

[Bug c++/31187] [4.2/4.3 regression] extern declaration of variable in anonymous namespace prevents use of its address as template argument

[jason at gcc dot gnu dot org]

------- Comment #7 from jason at gcc dot gnu dot org  2007-04-02 18:49 -------
Subject: Bug 31187

Author: jason
Date: Mon Apr  2 18:49:21 2007
New Revision: 123432

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=123432
Log:
        PR c++/31187                                                            
        * typeck.c (cp_type_readonly): New fn.                                  
        * cp-tree.h: Declare it.                                                
        * decl.c (start_decl): Set implicit DECL_THIS_STATIC here.              
        (cp_finish_decl): Not here.                                             

        * g++.dg/ext/visibility/anon3.C: New test.                              

Added:
    trunk/gcc/testsuite/g++.dg/ext/visibility/anon3.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/cp-tree.h
    trunk/gcc/cp/decl.c
    trunk/gcc/cp/typeck.c
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31187

[Bug c++/31187] [4.2/4.3 regression] extern declaration of variable in anonymous namespace prevents use of its address as template argument

[jason at gcc dot gnu dot org]

------- Comment #8 from jason at gcc dot gnu dot org  2007-04-02 20:12 -------
Subject: Bug 31187

Author: jason
Date: Mon Apr  2 20:12:15 2007
New Revision: 123434

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=123434
Log:
        PR c++/31187                                                            
        * typeck.c (cp_type_readonly): New fn.                                  
        * cp-tree.h: Declare it.                                                
        * decl.c (start_decl): Set implicit DECL_THIS_STATIC here.              
        (cp_finish_decl): Not here.                                             

        * g++.dg/ext/visibility/anon3.C: New test.                              

Added:
    branches/gcc-4_2-branch/gcc/testsuite/g++.dg/ext/visibility/anon3.C
      - copied unchanged from r123432,
trunk/gcc/testsuite/g++.dg/ext/visibility/anon3.C
Modified:
    branches/gcc-4_2-branch/gcc/cp/ChangeLog
    branches/gcc-4_2-branch/gcc/cp/cp-tree.h
    branches/gcc-4_2-branch/gcc/cp/decl.c
    branches/gcc-4_2-branch/gcc/cp/typeck.c
    branches/gcc-4_2-branch/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31187

[Bug c++/31187] [4.2/4.3 regression] extern declaration of variable in anonymous namespace prevents use of its address as template argument

[jason at gcc dot gnu dot org]

------- Comment #9 from jason at gcc dot gnu dot org  2007-04-09 22:43 -------
Fixed in 4.2 branch and trunk.


-- 

jason at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31187

[Bug c++/31187] [4.2/4.3 regression] extern declaration of variable in anonymous namespace prevents use of its address as template argument

[jakub at gcc dot gnu dot org]

------- Comment #10 from jakub at gcc dot gnu dot org  2007-06-26 11:57 -------
Subject: Bug 31187

Author: jakub
Date: Tue Jun 26 11:57:42 2007
New Revision: 126027

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=126027
Log:
2007-03-30  Jason Merrill  <jason@redhat.com>

        PR c++/31187
        * typeck.c (cp_type_readonly): New fn.
        * cp-tree.h: Declare it.
        * decl.c (start_decl): Set implicit DECL_THIS_STATIC here.
        (cp_finish_decl): Not here.

2007-04-02  Jason Merrill  <jason@redhat.com>

        PR c++/31187
        * g++.dg/ext/visibility/anon3.C: New test.

Added:
    branches/redhat/gcc-4_1-branch/gcc/testsuite/g++.dg/ext/visibility/anon3.C
Modified:
    branches/redhat/gcc-4_1-branch/gcc/cp/ChangeLog
    branches/redhat/gcc-4_1-branch/gcc/cp/cp-tree.h
    branches/redhat/gcc-4_1-branch/gcc/cp/decl.c
    branches/redhat/gcc-4_1-branch/gcc/cp/typeck.c
    branches/redhat/gcc-4_1-branch/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31187