bind inside #each block on destructured value

[aMediocreDad]

Describe the bug

When using destructuring with spread syntax in an #each block (keyed or not):

{#each objArray as {id, ...rest} (id)}
	<input bind:value={rest[someProperty]} />
{/each}

The bind fails, and e.g. what you type will be rejected (the value does not update).

Not using destructuring works as expected:

{#each objArray as data (data.id)}
	<input bind:value={data[someProperty]} />
{/each}

Edit:

Strangely, while testing I noticed that nested values within a rest element functions as expected:

{#each objArray as {id, ...rest} (id)}
	<input bind:value={rest.bar.someProperty} />
{/each}

Reproduction

https://svelte.dev/repl/761103ad2e254ee0a95454fc82c314c7?version=3.44.0

Logs

No errors output.

System Info

# Tested on FireFox (Win/macOS), Chrome (Win/macOS), and iOS webkit in REPL. 

System:
    OS: Windows 10 10.0.22000
    CPU: (8) x64 Intel(R) Core(TM) i7-9700K CPU @ 3.60GHz
    Memory: 19.86 GB / 31.92 GB
  Binaries:
    Node: 14.17.5 - C:\Program Files\nodejs\node.EXE
    npm: 7.20.6 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Chrome: 94.0.4606.81
    Edge: Spartan (44.22000.120.0), Chromium (94.0.992.50)
    Internet Explorer: 11.0.22000.120

Severity

annoyance

[RaiVaibhav]

seems like the input value change not changing the objArray because of the runtime hook object_without_properties which makes the nested value immutable.

[jasonlyu123]

object_without_properties returns a new object. But if you have a nested object the property would be referencing the same object.

[Conduitry]

As of 3.51.0, code like this will produce a compile-time warning - https://svelte.dev/repl/761103ad2e254ee0a95454fc82c314c7?version=3.51.0