System Information
windows 10 64bits
GTX 1050 TI latest driver

Blender Version
ver 2.80.54 hash: cc73d59ad580

Short description of error
stumbled upon this crash ,creating two armatures then parenting their bones in edit mode which causes a crash .i think it's due the addition of multi-object editing, now u can edit 2+ armatures at the same time, probably not the best way to parent them.

Exact steps for others to reproduce the error
add two or duplicate two armateurs then in multi-edit mode select the corresponding bones of each then parent them.....sometimes it parents them but they disappear and sometimes it crashes.