[Bug c++/77777] Use rich location to mark correct expression for "invalid use of non-static member function"

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77777

--- Comment #4 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
FWIW the location information is available in the frame above:

Breakpoint 6, invalid_nonstatic_memfn_p (loc=205792, expr=<function_decl
0x7ffff1a16900 f>, complain=3)
    at ../../src/gcc/cp/typeck.c:1834
1834                            expr);
(gdb) list
1829          if (complain & tf_error)
1830            {
1831              if (DECL_P (expr))
1832                {
1833                  error_at (loc, "invalid use of non-static member function
%qD",
1834                            expr);
1835                  inform (DECL_SOURCE_LOCATION (expr), "declared here");
1836                }

within EXPR_LOCATION (arg):

(gdb) up
#7  0x00000000007b1a65 in resolve_args (args=0x7ffff1a14460 = {...},
complain=3) at ../../src/gcc/cp/call.c:4012
4012          else if (invalid_nonstatic_memfn_p (input_location, arg,
complain))

(gdb) call inform (arg->exp.locus, "")
/tmp/pr77777.cc: In function ‘int main()’:
/tmp/pr77777.cc:11:9: note: 
       x.f
       ~~^

so this location could be passed to invalid_nonstatic_memfn_p and a fix-it hint
added.