Unknown prop using export let and export function

[frederikhors]

Maybe a bug in this REPL: https://svelte.dev/repl/79aa242f7e6d4af684099868189d3cb4?version=3.18.0

If you click on button "toggle modal" in console you should have this warning:

"<Form> was created with unknown prop 'saveForm'"

If you remove from Form.svelte

• the line: export let removeThis = null
• and the line: {removeThis}

the warning disappear.

Am I wrong?

[antony]

This looks like a bug, since saveForm is indeed declared, and removeThis should have no bearing on it. I'm going to mark it as such.

However, if you're trying to bind a variable through three layers of components like this I'd recommend using a store, since we're probably abusing bindings a bit using the current pattern, and that might cause unexpected results.

[mikebeaton]

Somewhat related to #4403 (comment) .

Is it really right that just two layers of bind: might (reasonably be expected to) cause unexpected results?

Naively, I think a new user would naturally expect that if nested bind works at all then it should be documented and tested and supported as working - even if it does, say, get slow at high levels of nesting, or blow up on really ridiculously large levels.