Automatic class string coercion is not reactive

[rChaoz]

Describe the bug

Considering this code:

class Test {
	thing = $state(0)
	toString() {
		return String(this.thing)
	}
}

const test = new Test()

Using {test} in the component template is not reactive (when thing changes), but {String(test)} is.

Reproduction

https://svelte.dev/playground/e44b1258b39c4477a38ccb9ecaa4cd21?version=5.20.0

annoyance

[brunnerh]

I think this is a "won't fix" kind of issue; this has also been raised in regards to SvelteDate.
To not bloat the compiler output for every variable reference, you should explicitly call .toString().

[Conduitry]

This has come up enough times now that it might make sense documenting this somewhere.

[Ocean-OS]

Yeah, this reminds me of #14854, and from that issue, it appears that #14803, #13525, #13054, #9860 #11012 and #10629 are also related. I'm fairly certain that at least one issue every other month is more than enough to warrant some sort of documentation.