Svelte 5: next 182 breaks Threlte apps

[michealparks]

Describe the bug

Upgrading a Threlte app to next 182 causes the following error to occur whenever one of Threlte's <T> components is a child of another <T> component:

render_tag_invalid_argument
The argument to `{@render ...}` must be a snippet function, not a component or a slot with a `let:` directive or some other kind of function. If you want to dynamically render one snippet or another, use `$derived` and pass its result to `{@render ...}`

	in HierarchicalObject.svelte
	in SceneGraphObject.svelte
	in T.svelte
	in Scene.svelte
	in HierarchicalObject.svelte
	in SceneGraphObject.svelte
	in RootScene.svelte
	in Context.svelte
	in Canvas.svelte
	in App.svelte

The <T> component does not use any let directives or slots in our next branch.

Any insight or help here would be appreciated!

Reproduction

Here is a link to the Svelte 5 repl with a minimal reproduction:

https://svelte-5-preview.vercel.app/#H4sIAAAAAAAAE5WRTU_DMAyG_4oJh4K0tvepTAMOnMZl48Q4RK2rRWriyvHKpqr_nX5s3QYTiFtsv7af16lVbgr0avpeK6ctqql6LEs1UbIvu8BXWAi2sactp10m8SmbUmZrtxZjS2KBGp61q7SHBnImC8FcNtz1xSkxzh3uJDiTL1N0eFBGcR9Fw55WlcSn-S4Z5va7kqEtnnWaQ77lspSZ3GCmpsJbbCajjV7-byNPtHtBsii8n8AC_WYp2mWas4UWZKOL0WNnEYOL5tXvB7iwVt-aHHrktrCKulWDzZswhDeXkrXoBGI4voSAscKWAJmJIQwH_So6Y-7P0yevsg_HG7fVscmbP2FeCTIS8Hsnege68AS5NoU_EYDxD7XDz_Pr3d03I8xYvwZ1FH7n-vm3H80XlG4R_q4CAAA=

Logs

No response

System Info

System:
    OS: macOS 14.5
    CPU: (8) arm64 Apple M2
    Memory: 163.63 MB / 16.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 20.11.0 - /usr/local/bin/node
    npm: 10.2.4 - /usr/local/bin/npm
    pnpm: 9.4.0 - ~/Library/pnpm/pnpm
  Browsers:
    Chrome: 126.0.6478.127
    Safari: 17.5

Severity

blocking an upgrade

[huntabyte]

Duplicate of #12414 ?

[Conduitry]

Yup, it's fixed by #12421 - https://svelte-5-preview-mrnyyju6m-svelte.vercel.app/#H4sIAAAAAAAACp2STU_CQBCG_8q4mlBiS_WKBTUSEy540MSD9dBsB9jYzm52B9Q0_e9mKR8FJSEe5_uZmbcSU1WgE_23SlBWouiLe2NEKPjbeMMtsWAUoXB6YaX3JE5aZXiYUsqqNNoyvCqeP5MyBhmmVpeQil7ccvaaLqm48UUFMki9IIYBXDjOGIOrro9QytMFSVaaQJG0WCJx0IXKR1Juai4HcL1qU6eUxDsWSs6iCD61_VA0gwjwyxRKKg7BokS19N7MziCKhiklLbjVItW5W_PLuSpyixT4RdYp3bohGMMEMcccqlZwFatit7WS-KD7cTTS_F-8HdNIE6_AYJRxdiLN5OmlRaRKT8RHpv81ZL-tCEWpczVVmIs-2wXW4VZOrbzTZAUgNblGSRtVDaDj58KjV9eYCC086NJoQmIINm_qbPVVbe5Ue5EZq40LvMb2FZOrZXPeO4uUo91e97Z3-P4kbpJ_b_pe_wC9giVqRAMAAA==