bug(datepicker): It is announcing the date buttons type incorrectly as text elements

[zarend]

Reproduction

Steps to reproduce:

1. Open the Datepicker Examples
2. Go to the "Basic datepicker" demo
3. Activate "Open calendar" button from any section, say, "Single date selection"
4. Focus on any date value

Expected Behavior

It should announce the date values as buttons/links so that screen readers can understand them to be clickable

Actual Behavior

It is announcing the date values as text elements using VoiceOver

Environment

OS| Browser | Screen reader
macOS Catalina | Google Chrome 92.0.4515.131 | VoiceOver

Additional Notes

This is copied from an internal bug report found during a11y testing.

[zarend]

from @jelbourn

This will need some investigation to confirm the expected behavior. Each date here is a gridcell, which are selectable per ARIA spec, so treating them as buttons may not be the right thing to do.

[zarend]

@jelbourn , from what I can tell, Voiceover does not announce that gridcell's are intractable when they have aria-selected="true" or aria-selected="false". To back that up, a11ysupport.io's page on aria-select gridcell has a minimal example of this.

If we were to work around that, putting a button inside each td seems like the most reasonable approach to me.