[Bug fortran/86116] [6/7/8/9 Regression] Ambiguous generic interface not recognised

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86116

--- Comment #2 from janus at gcc dot gnu.org ---
The problem can be fixed by removing the following piece of code:


Index: gcc/fortran/interface.c
===================================================================
--- gcc/fortran/interface.c     (revision 263308)
+++ gcc/fortran/interface.c     (working copy)
@@ -735,12 +735,6 @@ compare_type (gfc_symbol *s1, gfc_symbol *s2)
   if (s2->attr.ext_attr & (1 << EXT_ATTR_NO_ARG_CHECK))
     return true;

-  /* TYPE and CLASS of the same declared type are type compatible,
-     but have different characteristics.  */
-  if ((s1->ts.type == BT_CLASS && s2->ts.type == BT_DERIVED)
-      || (s1->ts.type == BT_DERIVED && s2->ts.type == BT_CLASS))
-    return false;
-
   return gfc_compare_types (&s1->ts, &s2->ts) || s2->ts.type == BT_ASSUMED;
 }


This was added by Tobias in r201329 (for PR 57530), which is certainly the
origin of the regression. Unfortunately the commit does not include a test
case, nevertheless I expect that the patch above will trigger some testsuite
regressions (but haven't checked yet).