[Bug c++/66350] typename should be forbidden in inhering constructors

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66350

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |msebor at gcc dot gnu.org

--- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> ---
Here's a reduced test case compiled with -Wall in C++ 98 mode:

  $ cat t.cpp && ~/bin/gcc-5.1.0/bin/g++ -Wall -std=c++98 -c t.cpp
  template <class T> struct A { A (T) { } };
  template <class T> struct B: A<T> {
      using typename A<T>::A;
  };

  B<int> b (0);
  t.cpp:3:26: warning: inheriting constructors only available with -std=c++11
or -std=gnu++11
       using typename A<T>::A;
                          ^
I don't think gcc is incorrect in accepting the code either in C++ 98 mode as
an extension, or in C++ 11 mode.  In the latter mode, accepting it is in
keeping with the resolution of DR 147. Naming the constructor  (Clang accepts
the test case above in C++ 11 mode).  That is, when 'A<T>::A' nominates class
template A the name is instead taken to name the ctor of A.