Exported contants under namespace not reassignable

[MaxGraey]

export namespace ns {
  export const a: i32 = 1;
  export const b: i32 = a;
}

Output:

ERROR TS2304: Cannot find name 'a'.

   export const b: i32 = a;
                         ~

But this works:

export namespace ns {
  export const a: i32 = 1;
  export const b: i32 = ns.a;
}