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

[vgheorgh at gmail dot com]

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

--- Comment #2 from Vlad Gheorghiu <vgheorgh at gmail dot com> ---
(In reply to Martin Sebor from comment #1)
> 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.

I tried compiling your test with Clang but it fails with the same error,
http://melpon.org/wandbox/permlink/7sGeB2XfPOHkOFfN