=== tests/cases/compiler/externFunc.ts ===
declare function parseInt(s:string):number;
>parseInt : { (s: string, radix?: number): number; (s: string): number; }, Symbol(parseInt, Decl(lib.d.ts, 28, 38), Decl(externFunc.ts, 0, 0))
>s : string, Symbol(s, Decl(externFunc.ts, 0, 26))

parseInt("2");
>parseInt("2") : number
>parseInt : { (s: string, radix?: number): number; (s: string): number; }, Symbol(parseInt, Decl(lib.d.ts, 28, 38), Decl(externFunc.ts, 0, 0))
>"2" : string