Type narrowing fails to account for multiple conditions

Bug Report

🔎 Search Terms

type narrowing

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about _________

⏯ Playground Link

https://tsplay.dev/mAJ91W

💻 Code

function isNaN(x: unknown): x is number {
	return x !== x;
}
function SameValue(x: unknown, y: unknown): x is typeof y {
	if (x === y) { // 0 === -0, but they are not identical.
		if (x === 0) { return 1 / x === 1 / y; }
		return true;
	}
	return isNaN(x) && isNaN(y);
};

🙁 Actual behavior

The y in 1 / y has a type error.

🙂 Expected behavior

Since this is inside a block where x === y, and also where x === 0, TS should be able to statically know that x and y are of type number (since both of them is definitively a zero, either +0 or -0). I shouldn't need the y === 0 check just to please TS.

Reproduce the narrowing behavior in the linked TypeScript Playground using the provided SameValue example, then start by tracing how the checker handles the nested x === y and x === 0 conditions. Done means the existing 1 / y expression type-checks without adding a separate y === 0 check, with coverage for the reported case.