Array.prototype.flat definitions are inaccurate

Code

const x = [1, [[2]]];
const y: never = x.flat();

Expected behavior:
I expect the following error:

Type '(1 | [2])[]' is not assignable to type 'never'.

or with more general types,

Type '(number | number[])[]' is not assignable to type 'never'.

This should actually be pretty easy to implement by simply unwrapping the array type (see link below).

Actual behavior:
I instead see

Type 'any[]' is not assignable to type 'never'.

Playground Link:
Using the current definitions
What I expect should happen

Related Issues:
None found.

Duplicate #29604 or at least just another case we should consider there when examining its definition

Related Issues: None found.

👁👁

I searched [Array flat definition] - apparently I should have left off "definition".

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