Stick finger into a couple more holes in the leaky dike of

modifyAggrefQual.  This routine really, really needs to be retired, but
until we have subselects in FROM there's no chance of doing the job right.
In the meantime try to respond to unhandlable cases with elog rather than
coredump.

src/backend/rewrite/rewriteHandler.c

@@ -6,7 +6,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.58 1999/10/01 04:08:24 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.59 1999/10/02 04:42:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -530,6 +530,13 @@ modifyAggrefMakeSublink(Expr *origexp, Query *parsetree)
 	subquery->targetList = lcons(tle, NIL);
 	subquery->qual = modifyAggrefDropQual((Node *) parsetree->qual,
 										  (Node *) origexp);
+	/*
+	 * If there are still aggs in the subselect's qual, give up.
+	 * Recursing would be a bad idea --- we'd likely produce an
+	 * infinite recursion.  This whole technique is a crock, really...
+	 */
+	if (checkQueryHasAggs(subquery->qual))
+		elog(ERROR, "Cannot handle aggregate function inserted at this place in WHERE clause");
 	subquery->groupClause = NIL;
 	subquery->havingQual = NULL;
 	subquery->hasAggs = TRUE;
@@ -576,10 +583,18 @@ modifyAggrefQual(Node *node, Query *parsetree)
 			SubLink    *sub = modifyAggrefMakeSublink(expr,
 													  parsetree);
 			parsetree->hasSubLinks = true;
+			/* check for aggs in resulting lefthand... */
+			sub->lefthand = (List *) modifyAggrefQual((Node *) sub->lefthand,
+													  parsetree);
 			return (Node *) sub;
 		}
 		/* otherwise, fall through and copy the expr normally */
 	}
+	if (IsA(node, Aggref))
+	{
+		/* Oops, found one that's not inside an Expr we can rearrange... */
+		elog(ERROR, "Cannot handle aggregate function inserted at this place in WHERE clause");
+	}
 	/* We do NOT recurse into subselects in this routine.  It's sufficient
 	 * to get rid of aggregates that are in the qual expression proper.
 	 */