Proposed resolution (approved by CWG 2026-10-27):

Change in 9.3.4.6 [dcl.fct] paragraph 4 as follows:

...

  void h(int x(const int));  // #3
  void h(int (*)(int)) {}    // defines #3

  void j(int[0]);            // error: int[0] is not a valid type

(From submission #797.)

Clarify that a zero-size array as a function parameter is ill-formed, because the array-to-pointer canonicalization happens later. There is implementation divergence.