tests/cases/compiler/lambdaArgCrash.ts(27,25): error TS2304: Cannot find name 'ItemSet'. tests/cases/compiler/lambdaArgCrash.ts(29,14): error TS2345: Argument of type '(items: any) => void' is not assignable to parameter of type '() => any'. ==== tests/cases/compiler/lambdaArgCrash.ts (2 errors) ==== class Event { private _listeners: any[] = []; constructor () { // TODO: remove this._listeners = []; } add(listener: () => any): void { /// Registers a new listener for the event. /// The callback function to register. this._listeners.push(listener); } } class ItemSetEvent extends Event { add(listener: (items: ItemSet) => void ) { ~~~~~~~ !!! error TS2304: Cannot find name 'ItemSet'. super.add(listener); ~~~~~~~~ !!! error TS2345: Argument of type '(items: any) => void' is not assignable to parameter of type '() => any'. } }