//// [thisInSuperCall2.ts] class Base { constructor(a: any) {} } class Foo extends Base { public x: number; constructor() { super(this); // no error } } class Foo2 extends Base { public x: number = 0; constructor() { super(this); // error } } //// [thisInSuperCall2.js] var __extends = (this && this.__extends) || function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; function __() { this.constructor = d; } __.prototype = b.prototype; d.prototype = new __(); }; var Base = (function () { function Base(a) { } return Base; })(); var Foo = (function (_super) { __extends(Foo, _super); function Foo() { _super.call(this, this); // no error } return Foo; })(Base); var Foo2 = (function (_super) { __extends(Foo2, _super); function Foo2() { _super.call(this, this); // error this.x = 0; } return Foo2; })(Base);