[boost] Using allocator rebind on an incomplete type

In trying to clean up some code in Boost.Pool, I've run afoul of some code in Microsoft's implementation of the STL where they are using allocator::rebind on an incomplete type. Something like this: struct Node; // Incomplete! template<typename T, typename Alloc> struct List { Alloc<T>::rebind<Node>::other::pointer node_p; ... } I believe that attempting to instantiate an allocator with an incomplete type is illegal so, by extension, I would have assumed that attempting to rebind on an incomplete type would also be illegal, no? -Chris