Svelte 5 + SvelteKit: Warning "slot is missing" if {render children()} is used inside +layout.svelte

[johannesmutter]

Describe the bug

+layout.svelte file requires either a <slot /> or {@render children()} to render child routes.
However in Svelte 5 if we use {@render children()} we will get this warning in the console:

src/routes/+layout.svelte
`<slot />` missing — inner content will not be rendered

Adding this commented line will hide the warning <!-- <slot /> -->

Reproduction

This simple REPL demonstrates the issue:
https://www.sveltelab.dev/f16ajcfi2z70ueq?files=.%2Fsrc%2Froutes%2F%2Blayout.svelte

(see the console)

Logs

src/routes/+layout.svelte
`<slot />` missing — inner content will not be rendered

### System Info

```shell
"@sveltejs/kit": "^1.27.4",
	   "svelte": "^5.0.0-next.1",

Severity

annoyance

[brunnerh]

Duplicate of:

• Svelte 5: prompt "<slot /> missing" when using children snippet instead of <slot /> in +layout.svelte kit#11127

[geoffrich]

Thanks, closing as a duplicate of sveltejs/kit#11127. It will need to be fixed in the Kit repo anyway.