Tuple suffix associated with rest element in a binding pattern

[JsonFreeman]

You could imagine that someone had the following:

var tuple: [string, number] = ["", 0];
var [a, ...b] = tuple;

Right now, a is string, but b is (string | number)[]. This is because the type associated with b is the array of the element type of the incoming array.

But it would be really nice if b was [number], or at least number[]. You should be able to chop off the rest of the elements in the incoming array, and only use those for the type associated with a rest element.

[RyanCavanaugh]

The idea as I understand it is that any spread operator assumes that "all of the rest of the values" are in the domain of the tuple-specified types.

e.g.

var tuple: [string, number] = ["", 0];
tuple.push(42); // ok
tuple.push('hello'); // ok
tuple.push(window); // err
var [a, ...b] = tuple; // desired: b: Array<string|number>