// Initializer expressions for instance member variables are evaluated in the scope of the class constructor body but are not permitted to reference parameters or local variables of the constructor. class C { a = z; // error b: typeof z; // error c = this.z; // error d: typeof this.z; // error constructor(x) { z = 1; } } class D { a = z; // error b: typeof z; // error c = this.z; // error d: typeof this.z; // error constructor(x: T) { z = 1; } }