[Bug c++/61470] New: ill-formed friend declaration(s) with default-arguments not caught

["filip.roseen at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61470

            Bug ID: 61470
           Summary: ill-formed friend declaration(s) with
                    default-arguments not caught
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: filip.roseen at gmail dot com

Created attachment 32920
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=32920&action=edit
testcase.cpp

struct A {
  friend void f(int=0);   // (A), ill-formed, [dcl.fct.default]p4
  friend void g(int=0){}; // ( ), legal
};

void g(int);              // (B), ill-formed, [dcl.fct.default]p4

int main () { }

---------------------

(A) and (B) are violating the following sentence from [dcl.fct.default]p4:

 > If a friend declaration specifies a default argument expression, that
 > declaration shall be a definition and shall be the only declaration of
 > the function or function template in the translation unit.