Index: src/Parser/ParseNode.h
===================================================================
--- src/Parser/ParseNode.h	(revision 1b299967c6b00690fea8f261aa12be0524f73546)
+++ src/Parser/ParseNode.h	(revision fe84230d44afd91fb519712a68f209d0452629d3)
@@ -109,5 +109,5 @@
 	ExpressionNode * set_extension( bool exten ) { extension = exten; return this; }
 
-	void print( std::ostream &os, int indent = 0 ) const {}
+	virtual void print( std::ostream &os, int indent = 0 ) const override {}
 	void printOneLine( std::ostream &os, int indent = 0 ) const {}
 
@@ -187,5 +187,5 @@
 //##############################################################################
 
-class TypeData;
+struct TypeData;
 
 class DeclarationNode : public ParseNode {
@@ -271,6 +271,6 @@
 	}
 
-	void print( std::ostream &os, int indent = 0 ) const;
-	void printList( std::ostream &os, int indent = 0 ) const;
+	virtual void print( std::ostream &os, int indent = 0 ) const override;
+	virtual void printList( std::ostream &os, int indent = 0 ) const override;
 
 	Declaration * build() const;
@@ -345,6 +345,6 @@
 	virtual StatementNode * append_last_case( StatementNode * );
 
-	virtual void print( std::ostream &os, int indent = 0 ) {}
-	virtual void printList( std::ostream &os, int indent = 0 ) {}
+	virtual void print( std::ostream &os, int indent = 0 ) const override {}
+	virtual void printList( std::ostream &os, int indent = 0 ) const override {}
   private:
 	std::unique_ptr<Statement> stmt;