Re: [PATCH] Fix PR56480 aka DR374. Allow explicit specialization in enclosing namespace.

[Jason Merrill]

On 11/08/2014 06:57 AM, Markus Trippelsdorf wrote:
+++ b/gcc/testsuite/g++.old-deja/g++.pt/explicit73.C
@@ -7,9 +7,9 @@
 // the template
 namespace N {
-  template <class T> class foo;  // { dg-error "" } referenced below
+  template <class T> class foo;  // { dg-error "" "" { target { ! c++11 } } } 
referenced below
 }

 using namespace N;

-template <> class foo<void>; // { dg-error "" } invalid specialization
+template <> class foo<void>; // { dg-error "" "" { target { ! c++11 } } } 
invalid specialization

This should still get an error in C++11 mode.

I think we also need to test this:

namespace A {
  namespace B {
    template <class T> void f();
  }
  using namespace B;
}

template<> void A::f<>(); // { dg-error "" }

I think your code won't catch this, because we need to know what the 
explicit namespace was, not just whether there was one.

Can we handle this in check_explicit_specialization rather than all the 
way down in register_specialization?

Jason