toString does not work in u64 array

[bowenwang1996]

Consider the following two functions

export function test(): string {
  let a: u64 = 1;
  return a.toString();
}

export function test1(): string {
  let arr: u64[] = Array.create<u64>(1);
  arr[0] = 1;
  return arr[0].toString();
}

The first one compiles but the second one doesn't and the error is

ERROR TS2339: Property 'toString' does not exist on type 'u64'.

   return arr[0].toString();
                 ~~~~~~~~

Fiddle example here

[bowenwang1996]

@dcodeIO is this related to #473?

[dcodeIO]

Possibly. Either that, or it's missing to pick up the backing U64 class somewhere.