=== tests/cases/compiler/objectMembersOnTypes.ts ===
interface I {}
>I : I

class AAA implements I { }
>AAA : AAA
>I : I

var x: number;
>x : number

x.toString();
>x.toString() : string
>x.toString : (radix?: number) => string
>x : number
>toString : (radix?: number) => string

var i: I;
>i : I
>I : I

i.toString(); // used to be an error
>i.toString() : string
>i.toString : () => string
>i : I
>toString : () => string

var c: AAA;
>c : AAA
>AAA : AAA

c.toString(); // used to be an error
>c.toString() : string
>c.toString : () => string
>c : AAA
>toString : () => string