Cannot set readonly property in IIFE

[medikoo]

🔎 Search Terms

"readonly", "iife"

🕗 Version & Regression Information

• This is the behavior in every version I tried

⏯ Playground Link

No response

💻 Code

class Foo {
	readonly bar: string = "";
	constructor() {
		(() => { this.bar = "test"; })();
	}
}

🙁 Actual behavior

Fails with Cannot assign to 'bar' because it is a read-only property. error

🙂 Expected behavior

Should work in exactly same way as:

class Foo {
	readonly bar: string = "";
	constructor() {
		this.bar = "test";
	}
}

Additional information about the issue

I assume that's expected for some reason, and I'd love to learn what are the logical grounds for that

[MartinJohns]

Essentially another duplicate of #9998. #58729 would likely fix this. This was nonsense, as pointed out by jcalz.

[jcalz]

Martin Johns (@MartinJohns) aren’t IIFEs already inlined for CFA? I’m guessing initialization of readonly fields must be handled separately.

(Also, I don't see how #58729 would help; at the very least, merely running that same code in a TS with some version of that PR in it doesn't seem to change anything. Not sure where adding immediate/deferred would make sense there either.)

[MartinJohns]

You're right, my mistake. I swear I saw this issue before, but can't find it. :-/