Add instance for `FromSep (tc_opaque P) Q1 Q2`
See discussion at !833 (diffs, comment 83516)
- Turns out the cost/comment for
FromAndis obsolete,FromAndis never used byiCombine - I removed the
Hint ModeforFromAndthat corresponds to it being used byiCombine - Turns out there was an instance for missing for
tc_opaque+FromSep - I added that instance with the correct cost + a better comment + a test case that used to fail prior to this MR