Handle Nop properly

Src/AST/Myc.Ast.Compiler.Binder.pas

@@ -46,12 +46,8 @@ type
 
         // --- Standard Traversal (Use inherited) ---
         function VisitKeyword(const Node: IKeywordNode): IAstNode; override;
-        function VisitRecurNode(const Node: IRecurNode): IAstNode; override;
         function VisitConstant(const Node: IConstantNode): IAstNode; override;
         function VisitCreateSeries(const Node: ICreateSeriesNode): IAstNode; override;
-        function VisitAddSeriesItem(const Node: IAddSeriesItemNode): IAstNode; override;
-        function VisitSeriesLength(const Node: ISeriesLengthNode): IAstNode; override;
-
     public
         constructor Create(const AInitialDescriptor: IScopeDescriptor);
         destructor Destroy; override;
@@ -222,20 +218,6 @@ begin
     Result := Node;
 end;
 
-function TAstBinder.VisitAddSeriesItem(const Node: IAddSeriesItemNode): IAstNode;
-begin
-    // Visit children
-    Result := inherited VisitAddSeriesItem(Node);
-    // Binding pass does not assign types.
-end;
-
-function TAstBinder.VisitSeriesLength(const Node: ISeriesLengthNode): IAstNode;
-begin
-    // Visit children
-    Result := inherited VisitSeriesLength(Node);
-    // Binding pass does not assign types.
-end;
-
 function TAstBinder.VisitLambdaExpression(const Node: ILambdaExpressionNode): IAstNode;
 var
     i: integer;
@@ -304,13 +286,6 @@ begin
     Result := TAst.LambdaExpr(newParams, newBody, scopeDescriptor, upvalues, hasNestedLambdas);
 end;
 
-function TAstBinder.VisitRecurNode(const Node: IRecurNode): IAstNode;
-begin
-    // Visit children
-    Result := inherited VisitRecurNode(Node);
-    // Binding pass does not assign types.
-end;
-
 function TAstBinder.VisitIdentifier(const Node: IIdentifierNode): IAstNode;
 var
     symbol: TResolvedSymbol;

Src/AST/Myc.Ast.Compiler.TypeChecker.pas

@@ -45,6 +45,7 @@ type
         function VisitAddSeriesItem(const Node: IAddSeriesItemNode): IAstNode; override;
         function VisitSeriesLength(const Node: ISeriesLengthNode): IAstNode; override;
         function VisitRecurNode(const Node: IRecurNode): IAstNode; override;
+        function VisitNop(const Node: INopNode): IAstNode; override;
 
         // Base cases (types are now set here)
         function VisitConstant(const Node: IConstantNode): IAstNode; override;
@@ -609,6 +610,12 @@ begin
     Result := TAst.AddSeriesItem(newSeries.AsIdentifier, newValue, newLookback, TTypes.Void);
 end;
 
+function TTypeChecker.VisitNop(const Node: INopNode): IAstNode;
+begin
+    // This is a leaf node. Assign its final type as Void.
+    Result := TAst.Nop(TTypes.Void);
+end;
+
 function TTypeChecker.VisitSeriesLength(const Node: ISeriesLengthNode): IAstNode;
 var
     seriesType: IStaticType;

Src/AST/Myc.Ast.Nodes.pas

@@ -160,9 +160,8 @@ type
         property StaticType: IStaticType read GetStaticType;
     end;
 
-    INopNode = interface(IAstNode)
+    INopNode = interface(IAstTypedNode)
     // A placeholder node for the UI (e.g., drag target).
-    // This node is illegal during compilation.
     end;
 
     IConstantNode = interface(IAstTypedNode)

Src/AST/Myc.Ast.pas

@@ -29,8 +29,7 @@ type
         class function CreateScope(Parent: IExecutionScope; const Descriptor: IScopeDescriptor = nil): IExecutionScope; static;
 
         // A No-Operation node, used as a placeholder/stub (e.g., for UI drop targets).
-        // This node is illegal in the compiler (Binder/TypeChecker will reject it).
+        class function Nop(const AStaticType: IStaticType = nil): IAstNode; static;
-        class function Nop: IAstNode; static;
 
         // --- Factory functions ---
         class function Constant(const AValue: TDataValue; const AStaticType: IStaticType = nil): IConstantNode; overload; static;
@@ -583,11 +582,11 @@ type
         property GenericDefinition: IGenericRecordDefinition read GetGenericDefinition;
     end;
 
-    TNopNode = class(TAstNode, INopNode)
+    TNopNode = class(TAstTypedNode, INopNode)
     private
         function GetKind: TAstNodeKind; override;
     public
-        constructor Create;
+        constructor Create(const AStaticType: IStaticType);
         function Accept(const Visitor: IAstVisitor): TDataValue; override;
         function AsNop: INopNode; override;
     end;
@@ -858,10 +857,10 @@ begin
         );
 end;
 
-class function TAst.Nop: IAstNode;
+class function TAst.Nop(const AStaticType: IStaticType = nil): IAstNode;
 begin
     // Factory function for the new Nop node
-    Result := TNopNode.Create;
+    Result := TNopNode.Create(TTypes.Unknown);
 end;
 
 class function TAst.Quasiquote(const AExpression: IAstNode): IQuasiquoteNode;
@@ -963,9 +962,9 @@ end;
 
 { TNopNode }
 
-constructor TNopNode.Create;
+constructor TNopNode.Create(const AStaticType: IStaticType);
 begin
-    inherited Create;
+    inherited Create(AStaticType);
 end;
 
 function TNopNode.Accept(const Visitor: IAstVisitor): TDataValue;