diff --git a/Src/AST/Myc.Ast.Evaluator.pas b/Src/AST/Myc.Ast.Evaluator.pas
index 3918af0..e55d3cd 100644
--- a/Src/AST/Myc.Ast.Evaluator.pas
+++ b/Src/AST/Myc.Ast.Evaluator.pas
@@ -126,7 +126,8 @@ var
     i: Integer;
     sourceAddresses: TArray<TResolvedAddress>;
     closureScope: IExecutionScope;
-    closureValue: TDataValue;
+    [weak]
+    closure: TDataValue.TFunc;
     visitorFactory: TVisitorFactory;
 begin
     sourceAddresses := Node.Upvalues;
@@ -145,7 +146,8 @@ begin
     var scopeDescriptor := Node.ScopeDescriptor;
     var params := Node.Parameters;
 
-    closureValue :=
+    // weak reference to break cyclic referencing
+    closure :=
         TDataValue.TFunc(
             function(const ArgValues: TArray<TDataValue>): TDataValue
             var
@@ -164,7 +166,7 @@ begin
 
                 // Capture 'Self' (slot 0) for recursion using the captured variable.
                 adr.SlotIndex := 0;
-                lambdaScope[adr] := closureValue;
+                lambdaScope[adr] := TDataValue(closure);
 
                 // Populate the actual parameters.
                 for i := 0 to High(ArgValues) do
@@ -180,7 +182,7 @@ begin
             end
         );
 
-    Result := closureValue;
+    Result := TDataValue(closure);
 end;
 
 function TEvaluatorVisitor.VisitFunctionCall(const Node: IFunctionCallNode): TDataValue;
diff --git a/Src/AST/Myc.Ast.Scope.pas b/Src/AST/Myc.Ast.Scope.pas
index 6f88862..d6020ff 100644
--- a/Src/AST/Myc.Ast.Scope.pas
+++ b/Src/AST/Myc.Ast.Scope.pas
@@ -140,7 +140,6 @@ begin
     case Address.Kind of
         akUpvalue:
         begin
-            // TODO Dieser Pfad wird nie erreicht!
             Assert(Assigned(FCapturedUpvalues), 'Attempt to access an upvalue in a scope with no closure context.');
             Assert(
                 (Address.SlotIndex >= 0) and (Address.SlotIndex < Length(FCapturedUpvalues)),