diff --git a/src/V3Gate.cpp b/src/V3Gate.cpp
index 4f6ebf02c..b6a94f475 100644
--- a/src/V3Gate.cpp
+++ b/src/V3Gate.cpp
@@ -64,6 +64,7 @@ class GateGraphBaseVisitor {
 public:
     virtual AstNUser* visit(GateLogicVertex* vertexp, AstNUser* vup=NULL) =0;
     virtual AstNUser* visit(GateVarVertex* vertexp, AstNUser* vup=NULL) =0;
+    virtual ~GateGraphBaseVisitor() {}
 };
 
 //######################################################################
diff --git a/src/V3Hashed.h b/src/V3Hashed.h
index 4c4038d1b..2d460f08d 100644
--- a/src/V3Hashed.h
+++ b/src/V3Hashed.h
@@ -48,6 +48,8 @@ public:
 struct V3HashedUserCheck {
     // Functor for V3Hashed::findDuplicate
     virtual bool check(AstNode*,AstNode*) =0;
+    V3HashedUserCheck() {}
+    virtual ~V3HashedUserCheck() {}
 };
 
 class V3Hashed : public VHashedBase {