[v2.2.2] Typecheck breaks on slots in the v-if block

[Xenossolitarius]

Vue - Official extension or vue-tsc version

2.2.2

VSCode version

1.97.2

Vue version

3.5.13

TypeScript version

5.7.3

System Info

System:
    OS: macOS 15.3
    CPU: (11) arm64 Apple M3 Pro
    Memory: 424.42 MB / 18.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 20.18.1 - ~/.nvm/versions/node/v20.18.1/bin/node
    npm: 10.8.2 - ~/.nvm/versions/node/v20.18.1/bin/npm
    pnpm: 10.4.0 - ~/.nvm/versions/node/v20.18.1/bin/pnpm
  Browsers:
    Chrome: 133.0.6943.55
    Edge: 133.0.3065.59
    Safari: 18.3

package.json dependencies

Steps to reproduce

Create a component with slots get error message.
Resolved when slots defined with macro defineSlots

What is expected?

No errors

What is actually happening?

vue-tsc --noEmit

src/components/input/Input.vue:395:30 - error TS4081: Exported type alias '__VLS_Slots' has or is using private name '__VLS_0'.

395 & { leading?: (props: typeof __VLS_0) => any }
~~~~~~~

src/components/input/Input.vue:396:31 - error TS4081: Exported type alias '__VLS_Slots' has or is using private name '__VLS_1'.

396 & { trailing?: (props: typeof __VLS_1) => any }>;
~~~~~~~

src/components/modal/Modal.vue:338:30 - error TS4081: Exported type alias '__VLS_Slots' has or is using private name '__VLS_15'.

338 & { default?: (props: typeof __VLS_15) => any }>;
~~~~~~~~

Found 3 errors in 2 files.

Errors Files
2 src/components/input/Input.vue:395
1 src/components/modal/Modal.vue:338

Link to minimal reproduction

No response

Any additional comments?

i think this bug fix has something to do with it
#5139

[KazariEX]

Please provide a minimal reproduction.

[Xenossolitarius]

https://github.com/Xenossolitarius/vue-tsc-2.2.2-bug

Here you go

pnpm i

pnpm typecheck

Should reproduce

src/components/modal/Modal.vue:338:30 - error TS4081: Exported type alias '__VLS_Slots' has or is using private name '__VLS_15'.

338 & { default?: (props: typeof __VLS_15) => any }>;
~~~~~~~~

[Xenossolitarius]

Oh so the problem is if the slot is in v-if

[KazariEX]

This is more like a TS problem.

We have been trying to simplify the code of codegen, but the results are always unsatisfactory😇

It would be better to use defineSlots instead of raw <slot>.

[Xenossolitarius]

tbh i hope SFC gets scrapped and we start using tsx/vine. I I think that would make your life much easier. Yea this would be a TS issue bcs this is basically how this works. But the type is available eh.

And this below produces "undefined" as a type too when i add the component to your repo. Seems more than one edge case.

<template>
	<div
	   v-if="open"
	>
	   <slot />
	</div>
</template>
  
<script setup lang="ts">
const open = true
</script>

<style scoped>
</style>

[KazariEX]

@Xenossolitarius Does disabling the ts compiler option composite have any impact on your project?

[Durss]

If that can be of any help, I have a similar issue with an unused template ref

I have a node with a ref='xxx' attribute that wasn't actually used in the JS part of the SFC.
Running a type-check led to this error:

Property 'my_template_ref' of exported interface has or is using private name '__VLS_5'.

Removing the unused ref attribute solved the issue.

I didn't get this issue with v2.1.10 but I get it on v2.2.2