PR69741: Bad error in formal with array scalar loop counters

[Steve Kargl]

On Sat, Nov 19, 2016 at 03:44:12PM +0100, Harald Anlauf wrote:
> > 
> > 2016-11-19  Harald Anlauf  <anlauf@gmx.de>
> > 
> > 	PR fortran/69741
> > 	* resolve.c (gfc_resolve_forall): Check for non-scalar index
> > 	variables.
> > 
> > 2016-11-19  Harald Anlauf  <anlauf@gmx.de>
> > 
> > 	PR fortran/69741
> > 	* gfortran.dg/forall_18.f90: New testcase.
> > 

Here's the patch that I committed.

Index: gcc/fortran/resolve.c
===================================================================
--- gcc/fortran/resolve.c	(revision 242624)
+++ gcc/fortran/resolve.c	(working copy)
@@ -9647,16 +9647,15 @@ gfc_resolve_forall (gfc_code *code, gfc_
   static gfc_expr **var_expr;
   static int total_var = 0;
   static int nvar = 0;
-  int old_nvar, tmp;
+  int i, old_nvar, tmp;
   gfc_forall_iterator *fa;
-  int i;
 
   old_nvar = nvar;
 
   /* Start to resolve a FORALL construct   */
   if (forall_save == 0)
     {
-      /* Count the total number of FORALL index in the nested FORALL
+      /* Count the total number of FORALL indices in the nested FORALL
          construct in order to allocate the VAR_EXPR with proper size.  */
       total_var = gfc_count_forall_iterators (code);
 
@@ -9664,19 +9663,25 @@ gfc_resolve_forall (gfc_code *code, gfc_
       var_expr = XCNEWVEC (gfc_expr *, total_var);
     }
 
-  /* The information about FORALL iterator, including FORALL index start, end
-     and stride. The FORALL index can not appear in start, end or stride.  */
+  /* The information about FORALL iterator, including FORALL indices start, end
+     and stride.  An outer FORALL indice cannot appear in start, end or stride.  */
   for (fa = code->ext.forall_iterator; fa; fa = fa->next)
     {
+      /* Fortran 20008: C738 (R753).  */
+      if (fa->var->ref && fa->var->ref->type == REF_ARRAY)
+	{
+	  gfc_error ("FORALL index-name at %L must be a scalar variable "
+		     "of type integer", &fa->var->where);
+	  continue;
+	}
+
       /* Check if any outer FORALL index name is the same as the current
 	 one.  */
       for (i = 0; i < nvar; i++)
 	{
 	  if (fa->var->symtree->n.sym == var_expr[i]->symtree->n.sym)
-	    {
-	      gfc_error ("An outer FORALL construct already has an index "
-			 "with this name %L", &fa->var->where);
-	    }
+	    gfc_error ("An outer FORALL construct already has an index "
+			"with this name %L", &fa->var->where);
 	}
 
       /* Record the current FORALL index.  */
Index: gcc/testsuite/gfortran.dg/forall_18.f90
===================================================================
--- gcc/testsuite/gfortran.dg/forall_18.f90	(nonexistent)
+++ gcc/testsuite/gfortran.dg/forall_18.f90	(working copy)
@@ -0,0 +1,16 @@
+! { dg-do compile }
+! PR fortran/69741 - improve error message for nonscalar FORALL index variables
+!
+subroutine check
+  integer :: ii(2), i
+  real :: a(3,2)
+
+  forall (ii(1)=1:3, i=1:2) ! { dg-error "scalar variable of type integer" }
+     a(ii(1),i) = ii(1) * i
+  end forall
+
+  forall (j=1:3, ii(2)=1:2) ! { dg-error "scalar variable of type integer" }
+     a(j,ii(2)) = j * ii(2)
+  end forall
+
+end subroutine check
-- 
Steve