[Bug c/103996] Enhancement: Better diagnostic for invalid reuse of a function name

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103996

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
C++ front-end produces:
<source>: In function 'void f()':
<source>:4:10: error: invalid types '<unresolved overloaded function
type>[int]' for array subscript
    4 |     index[0] = 0;
      |          ^

Which seems better.