diff --git a/src/code.h b/src/code.h
index 9501739..e7e779a 100644
--- a/src/code.h
+++ b/src/code.h
@@ -21,6 +21,8 @@ class Value;
 class Code
 {
 public:
+  virtual ~Code() { }
+  
   virtual size_t size() const = 0;
   virtual const Instruction& at(size_t i) const = 0;
   
diff --git a/src/types/traits.h b/src/types/traits.h
index 0ce8cce..1c946f1 100644
--- a/src/types/traits.h
+++ b/src/types/traits.h
@@ -166,6 +166,7 @@ class Iterator /*: public std::iterator<std::input_iterator_tag, Value, ptrdiff_
     virtual bool hasNext() const = 0;
     virtual void advance() = 0;
     virtual Value value() const = 0;
+    virtual ~Behavior() { }
   };
   
 private: