`assignment_value_stale` warning possible with function bindings

[brunnerh]

Describe the bug

This only happens in very specific circumstances, e.g. "binding" to a set-only property of a snippet argument.
The warning is not easy to understand in that context and will not happen with a regular property binding.

(The code behaves as expected so the warning feels like it might be a false positive.)

Reproduction

<script>
	let elementFunBind = $state();
	$inspect('fun', elementFunBind?.tagName);
	
	let elementPropBind = $state();
	$inspect('prop', elementPropBind?.tagName);

	let elementEvent = $state();
	$inspect('event', elementEvent?.tagName);
</script>

{#snippet funBind(context)}
	<!-- only this triggers the warning: -->
	<input value="via fun" bind:this={() => {}, e => context.element = e} />
{/snippet}
{@render funBind({ set element(e) { elementFunBind = e } })}

{#snippet propBind(context)}
	<textarea bind:this={context.element}>via prop</textarea>
{/snippet}
{@render propBind({ set element(e) { elementPropBind = e } })}

{#snippet event(context)}
	<button onclick={e => context.element = e.target}>via event</button>
{/snippet}
{@render event({ set element(e) { elementEvent = e } })}

Playground

Logs

System Info

REPL

Severity

annoyance