[Bug fortran/66544] [F03] ICE on function with procedure-pointer result in combination with implicit none

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66544

--- Comment #4 from janus at gcc dot gnu.org ---
Btw, I don't fully understand why "implicit none" should make any difference
here.

I can see that it would make a difference if you don't specify an interface in
the procedure statement:

module m
  implicit none
contains
  function f() result(z)
      procedure(), pointer :: z
  end
end module

But this version works fine, with and without "implicit none". In your original
test case the interface is fully specified, i.e. nothing is really 'implicit'.

I guess the actual problem is the self reference of the interface. We should
check if this is legal, and if not reject it.