Change a comment so hlint doesn't mistake it for a directive.
Also, fix extensions use in safe-lists/GADT.
Recreate BDD.hs so hlint can parse it. IDK why it detected some invalide byte code before.
Use hierarchical imports.
[HLint] Use any.
[HLint] Use catMaybes.
Fix encoding to UTF-8, so HLint can parse it.
[HLint] Use better pragmas (GADT.hs, Play.hs, Example/Betaered.hs).
According to HLint, ImplicitParams was not used. However, after removing it, GHC failed to build, and recommended enabling FlexibleInstances.