@@ -174,11 +174,11 @@
 	old = data[i]->object;
 	data[i]->object = [object retain];
 	[old release];
 }
 
-- (void)removeObjectForKey: (id)key
+- (void)removeObjectForKey: (id <OFCopying>)key
 {
 	uint32_t i, hash, last;
 
 	if (key == nil)
 		@throw [OFInvalidArgumentException newWithClass: isa