diff --git a/VERSION b/VERSION
index 960ac53..3663b2b 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.5.183
+1.5.184
diff --git a/base/netcmp.c b/base/netcmp.c
index be933b8..ab672ed 100644
--- a/base/netcmp.c
+++ b/base/netcmp.c
@@ -7245,7 +7245,8 @@ int MatchPins(struct nlist *tc1, struct nlist *tc2, int dolist)
    /* so apply only to black-box (CELL_PLACEHOLDER) entries.	*/ 
    /* (Semi-hack: Allow "!" global flag) */
 
-   if ((tc1->flags & CELL_PLACEHOLDER) && (tc2->flags & CELL_PLACEHOLDER)) {
+   if (((tc1->flags & CELL_PLACEHOLDER) && (tc2->flags & CELL_PLACEHOLDER)) ||
+	    (NodeClasses == NULL)) {
       ob1 = tc1->cell;
       bangptr1 = strrchr(ob1->name, '!');
       if (bangptr1 && (*(bangptr1 + 1) == '\0'))
@@ -7349,7 +7350,6 @@ int MatchPins(struct nlist *tc1, struct nlist *tc2, int dolist)
 			Tcl_NewStringObj(ob2->name, -1));
          }
 #endif
-	 result = 0;
 
 	 /* Before making a proxy pin, check to see if	*/
 	 /* flattening instances has left a port with a	*/
@@ -7368,6 +7368,10 @@ int MatchPins(struct nlist *tc1, struct nlist *tc2, int dolist)
 	    needclean2 = 1;
 	    continue;
 	 }
+	 else if (notempty == 1) {
+	    /* Flag this as an error */
+	    result = 0;
+	 }
 	 ob2->model.port = numnodes++;	// Assign a port order
 
 	 /* Add a proxy pin to tc1 */