[Bug c++/65943] New: template keyword required for base-specifier that names member of the current instantiation

["redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65943

            Bug ID: 65943
           Summary: template keyword required for base-specifier that
                    names member of the current instantiation
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Keywords: rejects-valid
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: redi at gcc dot gnu.org
  Target Milestone: ---

template<class A> struct X
{
    template<class B> struct Base;
    template<class B> struct Data;
};

template<class A>
template<class B>
struct X<A>::Data : X<A>::Base<B>
{ };


This fails to compile:

f.cc:9:33: error: ‘typename X<A>::Base’ names ‘template<class A> template<class
B> struct X<A>::Base’, which is not a type
 struct X<A>::Data : X<A>::Base<B>
                                 ^
f.cc:9:27: error: ‘typename X<A>::Base’ names ‘template<class A> template<class
B> struct X<A>::Base’, which is not a type
 struct X<A>::Data : X<A>::Base<B>
                           ^
f.cc:10:1: error: expected class-name before ‘{’ token
 { };
 ^

Clang and EDG accept it.

It compiles if the base-specifier is changed to X<A>::template Base<B>, but I
think the addition of "but the name is not a member of the current
instantiation" to C++11 14.2 [temp.names] p4 should make it valid.

In any case, http://open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1710 will
definitely make it valid. See also
http://open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1812 and
http://open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#314
>From gcc-bugs-return-485039-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Thu Apr 30 09:05:10 2015
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From: "paolo.carlini at oracle dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/59955] Segmentation fault on (re?)defining a struct template as function template, when inside a struct tempate
Date: Thu, 30 Apr 2015 09:05:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idY955

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED
   Target Milestone|---                         |6.0

--- Comment #7 from Paolo Carlini <paolo.carlini at oracle dot com> ---
Done.