Generic props are not handled properly in 3.x

[spaceemotion]

Vue - Official extension or vue-tsc version

3.2.8 (checked from 3.2.2)

VSCode version

1.118.1

Vue version

3.5.22

TypeScript version

5.9.3 (also is a bug on 6.0.3)

Steps to reproduce

I have the following component:

<script setup lang="ts" generic="TGroup extends {}, TGroups extends Record<string, TGroup> = Record<string, TGroup>">

defineProps<{
  groups: TGroups;
}>();
</script>

<template>
  <div>
    <template
      v-if="Object.keys(groups).length > 0"
    >
      <template
        v-for="(group, type) of groups"
        :key="type"
      >
        <slot
          :group="group"
          :type="type"
        />
      </template>
    </template>

    <slot
      v-else
      name="empty"
    />
  </div>
</template>

What is expected?

When hovering over the group variable in the v-for (to inspect its type), it should be TGroup

What is actually happening?

Instead, group is marked as unknown.

Any additional comments?

This is not an issue with v2.2.12 - and one of the things preventing us from upgrading.

[spaceemotion]

We have many other components that use generics, and they all fail in a similar way, e.g.:

<script lang="ts" setup generic="TKey extends string, TEntry extends { id: string }, TGroup extends {}">
const props = defineProps<{
  entries: Record<TKey, TEntry[]>;
  groups: Record<TKey, TGroup>;
  labelKey: keyof TGroup;
}>();
</script>

The types of TKey and TEntry are not propagated properly, so any passing, either via components or as slot props, falls back to the more regular string type - and not to the correct keys.