// @module: commonjs
// @declaration: true
// @filename: f1.ts
export class A {}
// @filename: f2.ts
export class B {
n: number;
}
// @filename: f3.ts
import {A} from "./f1";
import {B} from "./f2";
A.prototype.foo = function () { return undefined; }
declare module "./f1" {
interface A {
foo(): B;
// @filename: f4.ts
import "./f3";
let a: A;
let b = a.foo().n;