@@ -55,11 +55,11 @@
  * Sets a key to an object. A key can be any object.
  *
  * \param key The key to set
  * \param obj The object to set the key to
  */
-- set: (OFObject*)key
+- set: (OFObject <OFCopying>*)key
    to: (OFObject*)obj;
 
 /**
  * \param key The key whose object should be returned
  * \return The object for the given key or nil if the key was not found