diff --git a/lib/ast.js b/lib/ast.js
index f3df78fe..953d031a 100644
--- a/lib/ast.js
+++ b/lib/ast.js
@@ -92,7 +92,10 @@ var AST_Token = DEFNODE("Token", "type value line col pos endline endcol endpos
 
 var AST_Node = DEFNODE("Node", "start end", {
     clone: function() {
-        return new this.CTOR(this);
+        var cloned = new this.CTOR(this);
+        cloned.cloned_from = this;
+        
+        return cloned;
     },
     $documentation: "Base class of all AST nodes",
     $propdoc: {