[bug]: Base UI Combobox icon controls lack accessible names

[liljamesjohn]

Describe the bug

The Base UI Combobox registry component renders three icon-only buttons without accessible names:

• The default popup trigger created by ComboboxInput.
• The clear action rendered by showClear.
• The remove action automatically rendered by ComboboxChip.

Browser accessibility trees expose each control as an unnamed button. Consumers cannot label the internal trigger or chip-remove button, and ComboboxClear is not exported.

Base UI's own Combobox examples explicitly provide aria-label="Open popup", aria-label="Clear selection", and item-specific labels such as aria-label={Remove ${language.value}}.

Affected component/components

Combobox (Base UI variant)

How to reproduce

1. Create or use a Base UI shadcn project.
2. Run pnpm dlx shadcn@4.18.0 add combobox.
3. Render a ComboboxInput with its default trigger and inspect the accessibility tree. The trailing button has no name.
4. Render ComboboxInput showClear with a selected value. The clear button has no name.
5. Render a multiple combobox with ComboboxChip. The chip-remove button has no name.
6. Tab to and inspect each icon-only button with browser accessibility tools or a screen reader.

Expected: each button has a stable accessible name, with an item-specific name for chip removal where possible.

Actual: each button is exposed without an accessible name.

Reproduction link

Current registry source: https://github.com/shadcn-ui/ui/blob/1773ecfeeb4a04366978d353e69b5c7ded78dcb2/apps/v4/registry/bases/base/ui/combobox.tsx

Base UI reference: https://base-ui.com/react/components/combobox

Logs

Not applicable. This is visible in the rendered accessibility tree.

System Info

shadcn 4.18.0
Node.js v24.19.0
macOS 26.4.1
Chromium accessibility tree
Base UI registry variant

Before submitting

• I've made research efforts and searched the documentation.
• I've searched open and closed issues.