Parameters of type 'T' cannot be assigned to parameters of type 'UnwrapRefSimple<T>'. ts(2345)

[WangJincheng4869]

Vue version

3.5.18

Link to minimal reproduction

https://play.vuejs.org/#eNp9Uc1OAjEQfpWxFyDRJUZPuJCoIVEPapTEA+VAltml2G2b/qwkm313p92AHAyXpvP9tN/MtOzemKwJyCYsd4UVxoNDH8yMK1EbbT20YLGEDkqraxiQdMAVV2VQhRdagUfn88VsOIKWK4BCK+dBCjqm0ZgvlqvZcLka3Z2yEyCYBMtVgqM8a9YyYGaC2w6zLJMiOrr4VW+qXdW/OBw8oZQavrSVm4vBiKt83CenzFR4rI1ce6QKIN9ez9o2mbsuH1OVUKFM8NBc1XqDcsoZ8ZzBmMh8fOJnl8w7+r4UVbZzWtGQUpOcFbo2QqJ9M3EIjrNJ337k1pTu5yVh3ga8PODFFovvf/Cd20eMs3eLDm2DnB05v7YV+p6ef77inu5HktIHSeoz5Ac6LUPM2MsegtpQ7BNdSvucVi1UtXDzvUflDk3FoFHZJT1ntP7HM63/xb3JbpOPdsi6XyGEyoc=

Steps to reproduce

function test<T>() {
  const list = ref<T[]>([]);
  const li: T[] = [];
  list.value.push(...li);
}

What is expected?

The type should actually be the same, there should be no errors reported

What is actually happening?

The element type within ref has an extra layer of UnwrapRefSimple, causing an error that prevents inserting the element into the array.

System Info

System:
    OS: Windows 11 10.0.26100
    CPU: (16) x64 AMD Ryzen 9 7940H  w/ Radeon 780M Graphics     
    Memory: 6.82 GB / 31.22 GB
  Binaries:
    Node: 22.17.1 - D:\Program Files\nodejs\node.EXE
    npm: 10.9.2 - D:\Program Files\nodejs\npm.CMD
    pnpm: 10.14.0 - D:\Users\jcwang\AppData\Roaming\npm\pnpm.CMD
  Browsers:
    Edge: Chromium (133.0.3065.69)
    Internet Explorer: 11.0.26100.1882

Any additional comments?

I am unable to distinguish whether it is a problem with Vue or a problem with the Vue language tool. I have submitted two copies language-tools

[kkqy]

same problem.

function test<T>(value: T) {
  const map = reactive(new Map<string, T>())
  map.set('test', value)
}

类型“T”的参数不能赋给类型“UnwrapRefSimple”的参数。ts(2345)

I tried using the following code.

function test<T>(value: T) {
  const map = reactive(new Map<string, T>())
  map.set('test', value as UnwrapRefSimple<T>)
}

However, unfortunately, UnwrapRefSimple is not exported.

then I tried this code:

function test<T>(value: T) {
  const map = reactive(new Map()) as Reactive<Map<string,T>>
  map.set('test', value as UnwrapRefSimple<T>)
}

But the error still persists.

It seems that Vue 3's type system is not very friendly to generics, and TypeScript's type inference is overly complex.

[kkqy]

@WangJincheng4869
You can temporarily use the following code.

function test<T>() {
  const list = ref<T[]>([]) as Ref<T[]>
  const li: T[] = []
  list.value.push(...li)
}

However, this solution seems to be ineffective for "reactive".