[Bug c++/96498] Wrong location for function first declared as a friend in a template

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96498

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2020-08-06

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This happens even if the function has already been declared at namespace scope
prior to the friend declaration in the class template:

__attribute__((nonnull(1))) void foo(void*);

template<typename>
struct T {
  friend void foo(void*);
};

void bar()
{
  foo(0);
  T<int> t;
  foo(0);
}

attr.C: In function 'void bar()':
attr.C:11:8: warning: argument 1 null where non-null expected [-Wnonnull]
   11 |   foo(0);
      |        ^
attr.C:1:34: note: in a call to function 'void foo(void*)' declared 'nonnull'
    1 | __attribute__((nonnull(1))) void foo(void*);
      |                                  ^~~
attr.C:13:8: warning: argument 1 null where non-null expected [-Wnonnull]
   13 |   foo(0);
      |        ^
attr.C:5:15: note: in a call to function 'void foo(void*)' declared 'nonnull'
    5 |   friend void foo(void*);
      |               ^~~
attr.C:12:10: warning: unused variable 't' [-Wunused-variable]
   12 |   T<int> t;
      |          ^

I think the friend in the template should not change anything here, since the
function is already visible.