System Information
Operating system: MacOS Mojave 10.14.4
Graphics card: Intel HD 6000

Blender Version
Broken: (example: 2.80, edbf15d3c044, master, 2018-11-28, as found on the splash screen)
Worked: (optional)

Short description of error
If apply widget to bone in rig and then this widget modified in edit mode (in object mode is fine) -- then blender crashes

Exact steps for others to reproduce the error

1. Create armature with bone
2. Apply widget (default cube) to bone
3. Try to modify cube in edit mode