Logical nullish assignment together with nullish coalescing produces false positive for "use before assignment"

[AlCalzone]

TypeScript Version: 4.1.0-dev.20201015

Search Terms: logical nullish assignment use before assigned

Code

let x: boolean;
declare function getX(): boolean;
declare function maybeGetX(): boolean | undefined;

if (Math.random() > 0.5) {
	x = getX();
}

x; // x is used before being assigned (expected)

x ??= maybeGetX() ?? true;

x; // Error: x is used before being assigned (UNEXPECTED)

Expected behavior:
No error in the last line

Actual behavior:
Error: x is used before being assigned

Playground Link: Playground

Related Issues:

[MartinJohns]

Possibly related: #40494

[Kingwl]

Yes. It's the same reason of #40494

You can try this