Code coverage of different combinations of secondary conditions
is obviously not complete because there are so many of them, but
all main rules should be there.
The reason for CORRECT vs INVALID is that both words have the same
number of characters so calls line up, but look quite different.
Reviewers: #cycles, sergey
Reviewed By: #cycles, sergey
Subscribers: dingto, sergey, brecht
Differential Revision: https://developer.blender.org/D2130
138362a3c9