Re: c++/8772: Segmentation fault on 3 lines of template code

[Gabriel Dos Reis <gdr at integrable-solutions dot net>]

bangerth@dealii.org writes:

| Synopsis: Segmentation fault on 3 lines of template code
| 
| State-Changed-From-To: open->analyzed
| State-Changed-By: bangerth
| State-Changed-When: Mon Dec  2 12:45:29 2002
| State-Changed-Why:
|     Others have confirmed this already.
|     
|     However, just for the record: I fail to see how this can be
|     made legal: when you write A<n>::B to denote the template
|     type, B is a template dependent type, and one would think
|     one has to write a "typename" somewhere. But then we have
|       typename A<n>::B
|     which is not the name of a type, but of a template. I don't
|     know what the standard says here, but I don't see a way to
|     make it legal in any case.

This case seems to be forgotten by the standard.  I think the
following should make GCC happy.

  template<int n>
     struct D  {
       enum { 
         v = C<A<n>::template B>::v
       };
     };

Note the "template" keyword in front of B.

The closest you can find in the standard is 14.2/

    4
      When the name of a member template specialization appears after . or
      -> in a postfix-expression, or after nested-name-specifier in a
      qualified-id, and the postfix-expression or qualified-id explicitly
      depends on a template-parameter (14.6.2), the member template name
      must be prefixed by the keyword template. Otherwise the name is
      assumed to name a non-template. [ example not reproduced ]

    5
      If a name prefixed by the keyword template is not the name of a
      member template, the program is ill-formed.

-- Gaby