Operating system: Windows 10
Graphics card: AMD RX 580
Broken: 2.8 commit 96f762500ef9 (latest as of Jan 7th)
Short description of error
When trying to export models as OBJ with smoothing groups, an error occurs preventing the export.
Exact steps for others to reproduce the error
Take any model, and try to export it as an OBJ with the smoothing groups option selected in the export settings.
The only changes I made to the default settings were selection only enabled, smoothing groups enabled, and writing materials disabled.