Like normal (non-template) classes, class templates have an injected-class-name (Clause 11 [class]). The injected-class-name can be used with or without a template-argument-list. When it is used without a template-argument-list, it is equivalent to the injected-class-name followed by the template-parameters of the class template enclosed in <> . When it is used with a template-argument-list, it refers to the specified class template specialization, which could be the current specialization or another specialization.

Within the scope of a class template specialization or partial specialization, when the injected-class-name is not followed by a < , it is equivalent to the injected-class-name followed by the template-arguments of the class template specialization or partial specialization enclosed in <> . [Example:

    template<class T> class Y;
    template<> class Y<int> {
        Y* p;          // meaning Y<int>
        Y<char>* q;    // meaning Y<char>
    };

—end example]

The injected-class-name of a class template or class template specialization can be used either with or without a template-argument-list wherever it is in scope. [Example:

    template <class T> struct Base {
        Base* p;
    };
    template <class T> struct Derived: public Base<T> {
        typename Derived::Base* p;  // meaning Derived::Base<T>
    };

—end example]

A lookup that finds an injected-class-name (6.5.2 [class.member.lookup]) can result in an ambiguity in certain cases (for example, if it is found in more than one base class). If all of the injected-class-names that are found refer to specializations of the same class template, and if the name is followed by a template-argument-list, the reference refers to the class template itself and not a specialization thereof, and is not ambiguous. [Example:

    template <class T> struct Base { };
    template <class T> struct Derived: Base<int>, Base<char> {
        typename Derived::Base b;            // error: ambiguous
        typename Derived::Base<double> d;    // OK
    };

—end example]

When the normal name of the template (i.e., the name from the enclosing scope, not the injected-class-name) is used without a template-argument-list, it refers to the class template itself and not a specialization of the template. [Example:

    template <class T> class X {
        X* p;         // meaning X<T>
        X<T>* p2;
        X<int>* p3;
        ::X* p4;      // error: missing template argument list
                      // ::X does not refer to the injected-class-name
    };

—end example]