--- a/compiler/PPCNodeVisitor.st	Fri Jul 24 15:06:54 2015 +0100
+++ b/compiler/PPCNodeVisitor.st	Mon Aug 17 12:13:16 2015 +0100
@@ -53,7 +53,8 @@
 
 close: node
     self assert: (self isOpen: node) description: 'should be opened first!!'.
-    
+    openSet size > 500 ifTrue: [ self error: 'This seems to be a bit too much, isnt it?' ].
+        
     openSet remove: node.
     closeSet add: node
 !
@@ -68,6 +69,7 @@
 
 open: node
     self assert: (self isOpen: node) not description: 'already opened!!'.
+    openSet size > 100 ifTrue: [ self error: 'This seems to be a bit too much, isnt it?' ].
     openSet add: node
 !