Unless the HRA is a special-purpose HRA or only covers medical expenses after the minimum deductible limit for an insurance plan to be an HDHP has been met, the HRA is other coverage that disqualifies one from being eligible to contribute to an HSA.
https://www.treasury.gov/press-center/press-releases/Pages/js1548.aspx
https://www.treasury.gov/press-center/press-releases/Documents/rev_rul200445.pdf
