diff --git a/include/boost/intrusive/detail/tree_value_compare.hpp b/include/boost/intrusive/detail/tree_value_compare.hpp
index a05741e..62817ca 100644
--- a/include/boost/intrusive/detail/tree_value_compare.hpp
+++ b/include/boost/intrusive/detail/tree_value_compare.hpp
@@ -34,14 +34,25 @@ struct tree_value_compare
    typedef KeyOfValue   key_of_value;
    typedef Key          key_type;
 
-   explicit tree_value_compare(const key_compare &kcomp)
-      :  base_t(kcomp)
-   {}
 
    tree_value_compare()
       :  base_t()
    {}
 
+   explicit tree_value_compare(const key_compare &kcomp)
+      :  base_t(kcomp)
+   {}
+
+   tree_value_compare (const tree_value_compare &x)
+      :  base_t(x.base_t::get())
+   {}
+
+   tree_value_compare &operator=(const tree_value_compare &x)
+   {  this->base_t::get() = x.base_t::get();   return *this;  }
+
+   tree_value_compare &operator=(const key_compare &x)
+   {  this->base_t::get() = x;   return *this;  }
+
    const key_compare &key_comp() const
    {  return static_cast<const key_compare &>(*this);  }