diff --git a/pcbnew/pcb_expr_evaluator.h b/pcbnew/pcb_expr_evaluator.h
index aeeed1a108..19db5c53df 100644
--- a/pcbnew/pcb_expr_evaluator.h
+++ b/pcbnew/pcb_expr_evaluator.h
@@ -37,7 +37,7 @@ class BOARD_ITEM;
 
 class PCB_EXPR_VAR_REF;
 
-class PCB_EXPR_UCODE : public LIBEVAL::UCODE
+class PCB_EXPR_UCODE final : public LIBEVAL::UCODE
 {
 public:
     virtual LIBEVAL::VAR_REF* createVarRef( LIBEVAL::COMPILER *aCompiler,