Crash when equipping armor with right-click

Alright, I right-clicked a piece of armor to equip it. I expected to equip armor, like normal. however, when I did so, my game crashed.

Steps to reproduce:
1. Take any item equippable to an armor slot when right-clicked (including Elytra)
2. Right click with that armor slot empty.
3. Congratz, your game is broken.