What to say when someone is going to sleep during day? [duplicate]

It seems to be a silly question but I was puzzled when somebody bid me good night, when I was going to sleep at 1:00 PM. If somebody goes to sleep in the afternoon, is it correct to bid him "good night"? I think this is wrong.

It's a bit odd. I would have expected to hear "have a nice nap", as someone who's going to sleep at 1:00 pm is probably only going to sleep for an hour or two.

If you planned to sleep for seven or eight hours, starting at 1:00 p.m., that's longer than a nap. I guess in that case "sleep well" (or "rest well", or "sleep tight", if you prefer) would be more appropriate. "Sweet dreams" would technically work, but it's not usually used except with people you are very familiar with (children, romantic partners, family, etc.). You could also use "sleep well" at night — it's not restricted to napping or sleeping for long periods during the day.

Also, you can use "good night" for situations other than going to sleep. I often hear it used when people go their separate ways after spending some time at night together, they say "good night" as they are parting.

Yes, it is a bit odd. "Sleep well" or similar would be more appropriate.