12 Overloading [over]

12.4 Overloaded operators [over.oper]

12.4.6 Class member access [over.ref]

A class member access operator function is a function named operator-> that is a non-static member function taking no parameters.
For an expression of the form the operator function is selected by overload resolution ([over.match.oper]), and the expression is interpreted as
( postfix-expression . operator -> () ) -> template id-expression