This is simply a data point regarding my experience last year.
Last year, I had the following segments:
DFW-YYZ with AC (7 hour layover)
YYZ-VIE with OS (23 hour layover)
VIE-WAW with OS (22 hour layover)
WAW-PRG with LO
I was expecting to pick up my luggage at VIE. To my surprised, my luggage was checked through to WAW. I had to approach help desk to get my luggage at VIE.