Proposed resolution (September, 2012):

1. Add the following as a new paragraph following 13.7.8 [temp.alias] paragraph 2:

When the type-id in the declaration of alias template (call it A) consists of a simple-template-id in which the template-argument-list consists of a list of identifiers naming each template-parameter of A exactly once in the same order in which they appear in A's template-parameter-list, the alias template is equivalent to the template named in the simple-template-id (call it T) if A and T have the same number of template-parameters. [Footnote: This rule is transitive: if an alias template A is equivalent to another alias template B that is equivalent to a class template C, then A is also equivalent to C, and A and B are also equivalent to each other. —end footnote] [Example:

  template<typename T, U = T> struct A;

  template<typename V, typename W>
    using B = A<V, W>;                // equivalent to A

  template<typename V, typename W>
    using C = A<V>;                   // not equivalent to A:
                                      // not all parameters used

  template<typename V>
    using D = A<V>;                   // not equivalent to A:
                                      // different number of parameters

  template<typename V, typename W>
    using E = A<W, V>;                // not equivalent to A:
                                      // template-arguments in wrong order

  template<typename V, typename W = int>
    using F = A<V, W>;                // equivalent to A:
                                      // default arguments not considered

  template<typename V, typename W>
    using G = A<V, W>;                // equivalent to A and B

  template<typename V, typename W>
    using H = E<V, W>;                // equivalent to E

  template<typename V, typename W>
    using I = A<V, typename W::type>; // not equivalent to A:
                                      // argument not identifier

—end example]

2. Change 13.6 [temp.type] paragraph 1 as follows:

Two template-ids refer to the same class or function if

• ...

• their corresponding template template-arguments refer to the same or equivalent (13.7.8 [temp.alias]) templates.

[Example:

...declares x2 and x3 to be of the same type. Their type differs from the types of x1 and x4.

  template<class T template<class> class TT> struct X { };
  template<class> struct Y { };
  template<class T> using Z = Y<T>;
  X<Y<int> Y> y;
  X<Z<int> Z> z;

declares y and z to be of the same type. —end example]