=== tests/cases/compiler/arrayConcat2.ts ===
var a: string[] = [];
>a : string[]
>[] : undefined[]

a.concat("hello", 'world');
>a.concat("hello", 'world') : string[]
>a.concat : { <U extends string[]>(...items: U[]): string[]; (...items: string[]): string[]; }
>a : string[]
>concat : { <U extends string[]>(...items: U[]): string[]; (...items: string[]): string[]; }
>"hello" : string
>'world' : string

a.concat('Hello');
>a.concat('Hello') : string[]
>a.concat : { <U extends string[]>(...items: U[]): string[]; (...items: string[]): string[]; }
>a : string[]
>concat : { <U extends string[]>(...items: U[]): string[]; (...items: string[]): string[]; }
>'Hello' : string

var b = new Array<string>();
>b : string[]
>new Array<string>() : string[]
>Array : ArrayConstructor

b.concat('hello');
>b.concat('hello') : string[]
>b.concat : { <U extends string[]>(...items: U[]): string[]; (...items: string[]): string[]; }
>b : string[]
>concat : { <U extends string[]>(...items: U[]): string[]; (...items: string[]): string[]; }
>'hello' : string