[Bug fortran/28081] Undue compile-time error for zero-sized substring

[fxcoudert at gcc dot gnu dot org]

------- Comment #1 from fxcoudert at gcc dot gnu dot org  2006-06-19 11:39 -------
Here is a patch that fixes this problem (and gives a slightly better, IMHO,
error message):

Index: resolve.c
===================================================================
--- resolve.c   (revision 114721)
+++ resolve.c   (working copy)
@@ -2542,7 +2542,9 @@
          return FAILURE;
        }

-      if (compare_bound_int (ref->u.ss.start, 1) == CMP_LT)
+      if (compare_bound_int (ref->u.ss.start, 1) == CMP_LT
+         && (compare_bound (ref->u.ss.end, ref->u.ss.start) == CMP_EQ
+             || compare_bound (ref->u.ss.end, ref->u.ss.start) == CMP_GT))
        {
          gfc_error ("Substring start index at %L is less than one",
                     &ref->u.ss.start->where);
@@ -2570,9 +2572,11 @@
        }

       if (ref->u.ss.length != NULL
-         && compare_bound (ref->u.ss.end, ref->u.ss.length->length) == CMP_GT)
+         && compare_bound (ref->u.ss.end, ref->u.ss.length->length) == CMP_GT
+         && (compare_bound (ref->u.ss.end, ref->u.ss.start) == CMP_EQ
+             || compare_bound (ref->u.ss.end, ref->u.ss.start) == CMP_GT))
        {
-         gfc_error ("Substring end index at %L is out of bounds",
+         gfc_error ("Substring end index at %L exceeds the string length",
                     &ref->u.ss.start->where);
          return FAILURE;
        }


-- 

fxcoudert at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|0                           |1
           Keywords|                            |patch
      Known to fail|                            |4.2.0 4.1.2
   Last reconfirmed|0000-00-00 00:00:00         |2006-06-19 11:39:33
               date|                            |
   Target Milestone|---                         |4.1.2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28081