4.9 The super Keyword

The super keyword can be used in expressions to reference base class properties and the base class constructor.

4.9.1 Super Calls

Super calls consist of the keyword super followed by an argument list enclosed in parentheses. Super calls are only permitted in constructors of derived classes, as described in section 8.3.2.

A super call invokes the constructor of the base class on the instance referenced by this. A super call is processed as a function call (section 4.15) using the construct signatures of the base class constructor function type as the initial set of candidate signatures for overload resolution. Type arguments cannot be explicitly specified in a super call. If the base class is a generic class, the type arguments used to process a super call are always those specified in the extends clause that references the base class.

The type of a super call expression is Void.

The JavaScript code generated for a super call is specified in section 8.7.2.

4.9.2 Super Property Access

A super property access consists of the keyword super followed by a dot and an identifier. Super property accesses are used to access base class member functions from derived classes and are permitted in contexts where this (section 4.2) references a derived class instance or a derived class constructor function. Specifically:

• In a constructor, instance member function, instance member accessor, or instance member variable initializer where this references a derived class instance, a super property access is permitted and must specify a public instance member function of the base class.
• In a static member function or static member accessor where this references the constructor function object of a derived class, a super property access is permitted and must specify a public static member function of the base class.

Super property accesses are not permitted in other contexts, and it is not possible to access other kinds of base class members in a super property access. Note that super property accesses are not permitted inside function expressions nested in the above constructs because this is of type Any in such function expressions.

Super property accesses are typically used to access overridden base class member functions from derived class member functions. For an example of this, see section 8.4.2.

The JavaScript code generated for a super property access is specified in section 8.7.2.

TODO: Update section to include bracket notation in super property access.