[PATCH] Implement DR21

[Richard Smith]

LGTM.

It looks like we still don't reject this:

  struct S { template<typename T = int> friend void f() {} };
  template<typename> void f();

... but I'm happy for us to treat this as part of DR226 and call DR21 done.

On Sat, Jun 22, 2013 at 5:36 PM, David Majnemer
<david.majnemer at gmail.com> wrote:
> This patch implements CWG DR21 [*]
>
> Interestingly, we properly handled default template arguments on friend
> class members but not on just friend classes:
> struct A {
>   template <class T1> void foo();
> };
> class B {
>   template <class T1 = int> friend void A::foo();
> };
>
> [*] http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#21
>
> --
> David Majnemer