//// [extendAndImplementTheSameBaseType.ts] class C { foo: number bar() {} } class D extends C implements C { baz() { } } var c: C; var d: D = new D(); d.bar(); d.baz(); d.foo; //// [extendAndImplementTheSameBaseType.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 C = (function () { function C() { } C.prototype.bar = function () { }; return C; })(); var D = (function (_super) { __extends(D, _super); function D() { _super.apply(this, arguments); } D.prototype.baz = function () { }; return D; })(C); var c; var d = new D(); d.bar(); d.baz(); d.foo;