Infer the type of `item` in `v-for` incorrectly

[zcf0508]

Vue - Official extension or vue-tsc version

2.1.8

VSCode version

1.95.0-insider

Vue version

3.5.12

TypeScript version

5.6.3

System Info

No response

package.json dependencies

No response

Steps to reproduce

https://play.vuejs.org/#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

What is expected?

list type is T[], and item type should be T.

What is actually happening?

Type 'UnwrapRefSimple' is not assignable to type 'T'.

Link to minimal reproduction

https://play.vuejs.org/#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

Any additional comments?

https://github.com/vuejs/language-tools/pull/4902

I tested the code with the latest version of volar, and it raised a similar problem.

[KazariEX]

The error in latest version of volar was caused by another issue and has been reverted. Could you try explicit type constraints?

const list: Ref<T[]> = ref([]);

This is a core type issue.

[zcf0508]

It works in Vue Playground but doesn't work in VSCode with the latest Volar extension.

[KazariEX]

It will be fixed in the next version.

[KazariEX]

The above problem can be attributed to this part of the code:

let a: T = ref<T>(null!);

Because generic parameters in the template will not be dereferenced automatically. You can open a issue or discussion in the core.