Bug 38764

Summary: bogus 'changes meaning' error?
Product: gcc Reporter: Pawel Sikora <pawel_sikora>
Component: c++Assignee: Not yet assigned to anyone <unassigned>
Status: RESOLVED DUPLICATE    
Severity: normal CC: gcc-bugs
Priority: P3    
Version: 4.3.3   
Target Milestone: ---   
Host: Target:
Build: Known to work:
Known to fail: Last reconfirmed:

Description Pawel Sikora 2009-01-08 12:22:19 UTC
following code snipet is reducted testcase from external application.
g++ and comeau online accept/reject source differently.

template < class T >
struct A
{
};
template < class U >
struct B
{
#if 1
        typedef A< float > A; // <-- accepted by comeau but...
        // g++: error: declaration of typedef struct A<float> B<U>::A
        // g++: error: changes meaning of A from struct A<float>
#else
        typedef ::A< float > A; // <-- accepted by g++ but...
        // comeau: class member typedef may not be redeclared
        //         typedef ::A< float > A;
        //                              ^
#endif
};
Comment 1 Richard Biener 2009-01-08 12:50:05 UTC
I suggest filing a problem report with Comeau.  EDG accepts both in -strict_ansi mode.
Comment 2 Pawel Sikora 2009-01-08 12:56:05 UTC
(In reply to comment #1)
> I suggest filing a problem report with Comeau.  EDG accepts both in
> -strict_ansi mode.
> 

i've tested it on comeau online to verify g++ behaviour :)
Comment 3 pinskia@gmail.com 2009-01-08 19:16:12 UTC
Subject: Re:   New: bogus 'changes meaning' error?


On Jan 8, 2009, at 4:22 AM, "pluto at agmk dot net" <gcc-bugzilla@gcc.gnu.org 
 > wrote:

> following code snipet is reducted testcase from external application.
> g++ and comeau online accept/reject source differently.
>
> template < class T >
> struct A
> {
> };
> template < class U >
> struct B
> {
> #if 1
>        typedef A< float > A; // <-- accepted by comeau but...
>        // g++: error: declaration of typedef struct A<float> B<U>::A
>        // g++: error: changes meaning of A from struct A<float>
> #else
>        typedef ::A< float > A; // <-- accepted by g++ but...
>        // comeau: class member typedef may not be redeclared
>        //         typedef ::A< float > A;
>        //                              ^
> #endif
> };

GCC is correct.  This code is invalid but the standard says for this  
case no diagnostic is required so both compilers are correct according  
to the standard. Just that edg could be enchened to error about this  
case.


>
>
>
> -- 
>           Summary: bogus 'changes meaning' error?
>           Product: gcc
>           Version: 4.3.3
>            Status: UNCONFIRMED
>          Severity: normal
>          Priority: P3
>         Component: c++
>        AssignedTo: unassigned at gcc dot gnu dot org
>        ReportedBy: pluto at agmk dot net
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38764
>
Comment 4 Pawel Sikora 2009-01-09 19:39:32 UTC
as mentioned, gcc is correct.
Comment 5 Andrew Pinski 2018-03-31 17:41:35 UTC
*** Bug 85128 has been marked as a duplicate of this bug. ***
Comment 6 Andrew Pinski 2018-03-31 17:42:30 UTC
Dup of bug 34531.

*** This bug has been marked as a duplicate of bug 34531 ***