[Bug fortran/92990] INVALID code with NULLIFY – partially misleading error message "If bounds remapping is specified at (1), the pointer target shall not be NULL"

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92990

anlauf at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P5
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2019-12-19
     Ever confirmed|0                           |1

--- Comment #1 from anlauf at gcc dot gnu.org ---
How about a simple approach to catch this early?
Beware: this is untested.

Index: gcc/fortran/match.c
===================================================================
--- gcc/fortran/match.c (Revision 279592)
+++ gcc/fortran/match.c (Arbeitskopie)
@@ -4589,6 +4589,19 @@ gfc_match_nullify (void)
          goto cleanup;
        }

+      /* Check for valid array pointer object.  Bounds remapping is not
+        allowed with NULLIFY.  */
+      if (p->ref)
+       {
+         gfc_ref* remap;
+         for (remap = p->ref; remap; remap = remap->next)
+           if (!remap->next && remap->type == REF_ARRAY
+               && remap->u.ar.type != AR_FULL)
+             break;
+         if (remap)
+           goto syntax;
+       }
+
       /* build ' => NULL() '.  */
       e = gfc_get_null_expr (&gfc_current_locus);