Broken: 3b8ae85e3d3a (blender2.8 HEAD)
Short description of error
Emitter / duplicator visibility is affecting Cycles rendered hair.
Exact steps for others to reproduce the error
Original file is the following. A basic plane with hair and non visible emitter:
Now if you link the group and instance it in a new file:
In 2.79a it renders correctly, the emitter is invisible but the hair is visible. In 2.80 it's all invisible.