[Bug c++/102036] -Wmismatched-tags doesn't warn for explicit instantations

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102036

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=103703

--- Comment #3 from Martin Sebor <msebor at gcc dot gnu.org> ---
G++ also doesn't warn for more involved cases like the one in pr103703 (with
the ICE fixed):

template <typename T>
struct A
{
  struct B { };
};

template <typename T>
struct C
{
  friend class A<C>::B;       // { dg-warning "-Wmismatched-tags" "pr102036" {
xfail *-*-* } }
};

template struct C<int>;

Clang warns for the above but also suffers from a false positive below:

template <typename T>
struct D
{
  friend class A<D>::B;       // okay, specialized as class below
};

template <>
struct A<long>
{
  class B { };
};

template struct D<long>;