=== tests/cases/compiler/addMoreCallSignaturesToBaseSignature.ts ===
interface Foo {
>Foo : Foo

    (): string;
}

interface Bar extends Foo {
>Bar : Bar
>Foo : Foo

    (key: string): string;
>key : string
}

var a: Bar;
>a : Bar
>Bar : Bar

var kitty = a();
>kitty : string
>a() : string
>a : Bar