Svelte 5 legacy: transition not conveyed using $$restProps and svelte:element

[shinokada]

Describe the bug

When I use svelte transition and svelte:element with Svelte 4 works.
But when I try it with Svelte 5 legacy, it doesn't show any transition.

Code

+page.svelte

<script> 
  import Parent from "./Parent.svelte";
  import { blur, fade, slide } from 'svelte/transition';
</script>

<Parent transition={slide} params={{ duration: 700 }}>
  <h1>Page content</h1>
</Parent>

Parent.svelte

<script>
  import Child from "./Child.svelte";
</script>

<div>
<Child  {...$$restProps}>
  <slot />
</Child>
</div>

Child.svelte

<script lang="ts">
  import { type TransitionConfig } from 'svelte/transition';
  type TransitionFunc = (node: HTMLElement, params: any) => TransitionConfig;
	let visible = true;

  export let transition: TransitionFunc | undefined = undefined;
  export let params: object = {};
  export let tag: string = 'div';
</script>

<label>
	<input type="checkbox" bind:checked={visible} />
	visible
</label>

{#if visible && transition}
<svelte:element this={tag} transition:transition={params} >
  <slot />
</svelte:element>
{/if}

Reproduction

I create a simplified repo for this issue.

You can run with Svelte 4 and it works. But when you install svelte@next, the transition doesn't work.

Logs

No response

System Info

System:
    OS: macOS 14.6
    CPU: (10) arm64 Apple M2 Pro
    Memory: 38.78 MB / 16.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 20.14.0 - ~/.nvm/versions/node/v20.14.0/bin/node
    npm: 10.7.0 - ~/.nvm/versions/node/v20.14.0/bin/npm
    pnpm: 9.4.0 - /opt/homebrew/bin/pnpm
    bun: 1.1.8 - ~/.bun/bin/bun
  Browsers:
    Chrome: 126.0.6478.127
    Edge: 126.0.2592.81
    Safari: 17.6
  npmPackages:
    svelte: 4.2.18 => 4.2.18

Severity

blocking an upgrade

[webJose]

Here's a REPL repro of this: REPL