Re: [C++] Possible GCC bug

[Jiri Palecek <jpalecek at web dot de>]

Ulf Magnusson wrote:
> On Wed, Nov 14, 2012 at 6:10 PM, Piotr Wyderski
> <piotr.wyderski@gmail.com>  wrote:
> > The following snippet:
> >
> > class A {};
> > class B : public A {
> >
> >     typedef A super;
> >
> > public:
> >
> >     class X {};
> > };
> >
> >
> > class C : public B {
> >
> >     typedef B super;
> >
> >     class X : public super::X {
> >
> >        typedef super::X super;
> >     };
> > };
> >
> > compiles without a warning on Comeau and MSVC, but GCC (4.6.1 and
> > 4.7.1) failes with the following message:
> >
> > $ gcc -c bug.cpp
> > bug.cpp:18:24: error: declaration of âtypedef class B::X C::X::superâ
> > [-fpermissive]
> > bug.cpp:14:14: error: changes meaning of âsuperâ from âtypedef class B
> > C::superâ [-fpermissive]
> >
> > Should I file a report?
> >
> >      Best regards, Piotr
> Here's a two-line TC:
>
> typedef struct { typedef int type; } s1;
> struct S2 { s1::type s1; };
>
> Fails with GCC 4.6.3; succeeds with clang 3.0. Looks like a bug to me.
>
> /Ulf
In your example, GCC is in fact right. Basically, you mustn't have a name refer to two things in a class:

3.3.6/1: ... A name N used in a class S shall refer to the same declaration in its context and when re-evaluated in the
completed scope of S. No diagnostic is required for a violation of this rule. ...

Regards
JiÅÃ PaleÄek