Hope const number types can do simple arithmetic operations

[samchon]

When define a const Array type, its Array.length type also be the constant value. However, type of Array.length - 1 is not the constant value because TypeScript does not support minus operation between const number types.

Thus, I hope TypeScript to support the simple arithmetic operations on the const number types.

type SomeNumber = 3;
type SomeOperatedNumber = 3 - 1; // NOT POSSIBLE

function main(): void
{
    let someArray: [number, string, false] = [1, "something", false];
    let length: 3 = someArray.length;
    let lastIndex: number = someArray.length - 1; // not 2, but number
}

[RyanCavanaugh]

Duplicate #26382