Remove destructive methods in tuple type

[falsandtru]

I think, tuple type should not have destructive methods because these methods break consistency between the interface and actual properties.

• Array#push
• Array#pop
• Array#shift
• Array#unshift
• Array#splice

var t: [boolean, number];
t.shift(); // now actual t type is [number]

[DanielRosenwasser]

I'm not sure we'd be willing to take that breaking change, but there is discussion at #4988 (comment) regarding an alternative interface from tuple types.

[zpdDG4gta8XKpMCd]

@falsandtru, you might also find the following helpful, provided whole awkwardness of tuples in TypeScript:

interface T2<a, b> {
    0: a;
    1: b;
}
function t2<a, b>(one: a, another: b) : T2<a, b> {
    return <any> [one, another];
}

let pair = t2('hey', true);
let text = pair[0];
let flag = pair[1];
let problem = pair[2];

UPDATE: fixed indices

[mhegazy]

Tuples are just arrays. and thus can have these methods. at least this is the current design. @Aleksey-Bykov's answer should allow you to limit your tuples to a more strict subset.