=== tests/cases/compiler/externFunc.ts ===
declare function parseInt(s:string):number;
>parseInt : { (s: string, radix?: number): number; (s: string): number; }
>s : string

parseInt("2");
>parseInt("2") : number
>parseInt : { (s: string, radix?: number): number; (s: string): number; }
>"2" : string