https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77406
--- Comment #2 from Steve Kargl <sgk at troutmask dot apl.washington.edu> --- Previous patch was bogus. Try this one: Index: gcc/fortran/interface.c =================================================================== --- gcc/fortran/interface.c (revision 239833) +++ gcc/fortran/interface.c (working copy) @@ -1616,8 +1616,13 @@ gfc_compare_interfaces (gfc_symbol *s1, f1 = gfc_sym_get_dummy_args (s1); f2 = gfc_sym_get_dummy_args (s2); + /* Special case: No arguments. */ if (f1 == NULL && f2 == NULL) - return 1; /* Special case: No arguments. */ + return 1; + + /* Special case: only alternate return. */ + if (f1 && f1->sym == NULL && f2 && f2->sym == NULL) + return 1; if (generic_flag) {