[Bug c++/27665] [4.0/4.1/4.2 regression] ICE writing class instead of typename

["mmitchel at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #3 from mmitchel at gcc dot gnu dot org  2006-06-15 00:06 -------
The problem here is with the parser optimization by which the results of
parsing a nested-name-specifier is cached, even if the parser backs up.  Here,
we consider that "class A<N>::B::C" might be a class-head.  In that context,
the dependent name A<N>::B should be resolved.  Therefore, the saved version of
the nested-name specifier is the class A<N>::B, rather than typename A<N>::B. 
Then, since this is not in fact a class-head, we back up and try again, parsing
the construct as an elaborated-type-specifier.  In that context, we should get
the typename -- but do not, due to the caching.

However, in this case A<N>::B shouldn't really be permitted to refer to the
class, even if it were part of a class-head, as we A<N> is not the same thing
as the abstract uninstantiated A.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27665