How to interpret date in Slot resource

The Slot Resource has search parameters .

start parameter has type=date

The date leads to

but this date can be one of the types date,dateTime,instant,Period,Timing.

The confusion is that date type can be date or dateTime. So date can be date or can be not date.

date as a datetype is defined here

A date, or partial date (e.g. just year or year + month) as used in human communication. The format is YYYY, YYYY-MM, or YYYY-MM-DD, e.g. 2018, 1973-06, or 1905-08-23. There SHALL be no time zone . Dates SHALL be valid dates

So, the question is when I do search for Slots can I use timezone or cannot? I noticed that HAPI allows putting there time zone while it seems that date type restricts the search by YYYY-MM-DD , i.e. no time and time zone.

What is canonical (normative) rule for search by Slot date? Can date/time be used or should stick to date only?

date can only be date. It’s listed beside those other types, but date can’t be a timestamp or dateTime any more than it can be a boolean or an integer.

When you’re search slot, you’re using the ‘date’ search parameter ( As a result, you’re free to use timezone. As you’ll see in the ‘dragon’ comment at the bottom of that section, the behavior of timezones is still up in the air. There are lots of possible behaviors - ignore the timezone on the search parameter. Treat the timezone-specific search parameter and time-zone-absent Slot has having the same timezone. Treat the Slot date as having a timezone of the server’s default. Treat the Slot date as having a timezone based on the location for the resource the slot corresponds to.

For R4 and earlier versions of the specification, the specific behavior is up to the server.