v-model without v-model:modelValue not type checked in template when defineModel is used

[davidmatter]

Discussed in #4529

^{Originally posted by Quartoffel July 4, 2024}
Hey,

I have a problem that my v-model (or any v-* for that matter) are neither type checked nor show any intellisense information. Normal props work fine (even :model-value). I am not sure why this happens. Maybe someone has any ideas how to debug/fix this. Here are two pictures to show the issue in action:

1. Here it correctly throws an error because of type mismatch
   

2. Here it does not (and also does not show any Intellisense on hover):
   

Test2.vue is just:

<template>
  <div>{{ model }}</div>
</template>

<script setup lang="ts">
const model = defineModel<string>();
</script>

Information about my setup:
System:
OS: Windows 10 10.0.19045
CPU: (12) x64 AMD Ryzen 5 5600X 6-Core Processor
Memory: 16.40 GB / 31.93 GB
Binaries:
Node: 20.11.1 - C:\Program Files\nodejs\node.EXE
Yarn: 1.22.19 - C:\Program Files (x86)\Yarn\bin\yarn.CMD
npm: 10.2.4 - C:\Program Files\nodejs\npm.CMD
pnpm: 9.4.0 - ~\AppData\Local\pnpm\pnpm.CMD
Browsers:
Edge: Chromium (126.0.2592.87)
Internet Explorer: 11.0.19041.4355

Vue - Official/vue-tsc Version: 2.0.26
Vue: 3.4.31
Typescript: 5.5.3

[davidmatter]

Doesn't work:

  <Test2 v-model="model"></Test2>

Works

  <Test2 v-model:modelValue="model"></Test2>

Per https://vuejs.org/guide/components/v-model#basic-usage the full notation is not required for unnamed defineModels.

[so1ve]

Caused by 01f64ee?

[Quartoffel]

@so1ve Yes, i think this commit (or any introduced into 2.0.18) might be the cause. I tried with 2.0.17 and it correctly identifies the type of v-model. 2.0.18 shows the same symptoms as above.