Consider:

  template<class T>
  void f()
  {
    struct Y {
      using type = int;
    };
    Y::type y;  // error; missing typename
  }

Since lookup of Y always finds the local class, regardless of T, the requirement to apply typename is too strict.

Possible resolution:

Change in 13.8.3.2 [temp.dep.type] paragraph 1 as follows:

A name or template-id refers to the current instantiation if it is

• ...
• in the definition of a nested class of a class template, the name of the nested class referenced as a member of the current instantiation, or
• in the definition of a class template partial specialization or a member of a class template partial specialization, the name of the class template followed by a template argument list equivalent to that of the partial specialization (13.7.6 [temp.spec.partial]) enclosed in <> (or an equivalent template alias specialization)., or
• in the definition of a templated function, the name of a local class (11.6 [class.local].