NavigationMenuItem's `ui` type requires every slot key instead of allowing partial overrides

Environment

• Package Manager: npm
• @nuxt/ui: 4.11.1
• vue: 3.5.43
• Vue + Inertia.js (no Nuxt), using @nuxt/ui/vite with router: "inertia"
• Type-checked with vue-tsc --noEmit

Is this bug related to Nuxt or Vue?

Vue

Package

v4.x

Version

v4.11.1

Reproduction

No external sandbox — this is a pure type-definition issue, fully reproducible from the shipped .d.ts alone:

<script setup lang="ts">
import type { NavigationMenuItem } from '@nuxt/ui'

const items = computed<NavigationMenuItem[]>(() => [
  {
    label: 'Feed',
    to: '/feed',
    active: true,
    // Type error: missing 'label', 'link', 'content', 'item', and 18 more
    ui: { linkLeadingIcon: 'text-court-950' },
  },
])
</script>

Description

NavigationMenuItem['ui'] is typed as a Pick over the component's generated slots type:

// node_modules/@nuxt/ui/dist/runtime/components/NavigationMenu.vue.d.ts
ui?: Pick<NavigationMenu['slots'], 'item' | 'linkLeadingAvatarSize' | 'linkLeadingAvatar' | 'linkLeadingIcon' | 'linkLeadingChipSize' | 'linkLabel' | 'linkLabelExternalIcon' | 'linkTrailing' | 'linkTrailingBadgeSize' | 'linkTrailingBadge' | 'linkTrailingIcon' | 'label' | 'link' | 'content' | 'childList' | 'childLabel' | 'childItem' | 'childLink' | 'childLinkIcon' | 'childLinkWrapper' | 'childLinkLabel' | 'childLinkLabelExternalIcon' | 'childLinkDescription'>;

NavigationMenu['slots'] resolves to an index-signature type ({ [x: string]: SlotClass }), not an interface with individually optional keys. Picking specific literal keys off an index-signature type produces an object type where every picked key is required, since index signatures carry no per-property optionality for Pick to preserve.

The result: although ui itself is optional on NavigationMenuItem, supplying any ui object requires values for all ~21 picked slot keys — even though at runtime tv() merges partial slot overrides just fine. Overriding a single slot like linkLeadingIcon per-item (a use case asked about in #3683) is a TypeScript error.

Expected behavior: overriding a single slot on an item's ui prop should type-check, matching the runtime merge behavior — e.g. by wrapping the Pick result in Partial<...>:

ui?: Partial<Pick<NavigationMenu['slots'], /* ... */>>;

Current workaround: cast the object to the field's type to bypass the over-strict check:

ui: { linkLeadingIcon: 'text-court-950' } as NavigationMenuItem['ui'],

Additional context

The same Pick-based pattern (and likely the same issue) appears on other components' per-item ui fields, e.g. NavigationMenuChildItem.

Logs

error TS2322: Type '{ label: string; to: string; active: true; ui: { linkLeadingIcon: string; }; }' is not assignable to type 'NavigationMenuItem'.
  Types of property 'ui' are incompatible.
    Type '{ linkLeadingIcon: string; }' is missing the following properties from type
    'Pick<{ [x: string]: SlotClass; }, "label" | "link" | "linkLeadingIcon" | "content" | "item" | ... 14 more ... | "childLinkDescription">':
    label, link, content, item, and 18 more.

Start with node_modules/@nuxt/ui/dist/runtime/components/NavigationMenu.vue.d.ts and reproduce the issue using vue-tsc --noEmit with the provided NavigationMenuItem example. Check the related NavigationMenuChildItem declaration as well. Done means a single-slot ui override type-checks without a cast, while the existing NavigationMenuItem fields remain valid.