Index: libcfa/src/bits/collection.hfa
===================================================================
--- libcfa/src/bits/collection.hfa	(revision 8a81b092ecea5683a5987e76b0118ed12616f1c4)
+++ libcfa/src/bits/collection.hfa	(revision b3c8496a418823a0579dda2d3179e4d6e61a1c8b)
@@ -37,5 +37,4 @@
 
 	// 	bool listed( T * n ) {
-	// 		fprintf(stderr, "inappropriate listed used");
 	// 		return Next( (Colable *)n ) != 0p;
 	// 	}
Index: libcfa/src/bits/queue.hfa
===================================================================
--- libcfa/src/bits/queue.hfa	(revision 8a81b092ecea5683a5987e76b0118ed12616f1c4)
+++ libcfa/src/bits/queue.hfa	(revision b3c8496a418823a0579dda2d3179e4d6e61a1c8b)
@@ -3,5 +3,5 @@
 #include "bits/collection.hfa"
 
-forall( dtype T ) {
+forall( dtype T | { T *& Next ( T * ); bool listed ( T * ); } ) {
 	struct Queue {
 		inline Collection;								// Plan 9 inheritance
@@ -64,5 +64,5 @@
 			T & t = head( q );
 			if ( root ) {
-				root = Next( root );
+				root = Next( (T *)root );
 				if ( &head( q ) == &t ) {
 					root = last = 0p;					// only one element
@@ -142,5 +142,5 @@
 } // distribution
 
-forall( dtype T ) {
+forall( dtype T | { T *& Next ( T * ); bool listed ( T * ); } ) {
 	struct QueueIter {
 		inline ColIter;									// Plan 9 inheritance
Index: libcfa/src/bits/stack.hfa
===================================================================
--- libcfa/src/bits/stack.hfa	(revision 8a81b092ecea5683a5987e76b0118ed12616f1c4)
+++ libcfa/src/bits/stack.hfa	(revision b3c8496a418823a0579dda2d3179e4d6e61a1c8b)
@@ -3,5 +3,5 @@
 #include "bits/collection.hfa"
 
-forall( dtype T ) {
+forall( dtype T | { T *& Next ( T * ); bool listed ( T * ); } ) {
 	struct Stack {
 		inline Collection;								// Plan 9 inheritance
@@ -44,5 +44,5 @@
 			T & t = head( s );
 			if ( root ) {
-				root = ( T *)Next( root );
+				root = ( T *)Next( (T *)root );
 				if ( &head( s ) == &t ) root = 0p;		// only one element ?
 				Next( &t ) = 0p;
@@ -58,5 +58,5 @@
 
 
-forall( dtype T ) {
+forall( dtype T | { T *& Next ( T * ); bool listed ( T * ); } ) {
 	struct StackIter {
 		inline ColIter;									// Plan 9 inheritance