value
simplifyLevelConstraint :: ConstraintConstraint
cto simplify.-> List1 ConstraintOther constraints, enable simplification.
-> Maybe [Constraint]Just: list of constraints equal to the originalc.Nothing: no simplification possible.
simplifyLevelConstraint c cs turns an c into an equality
constraint if it is an inequality constraint and the reverse
inequality is contained in cs.
The constraints don't necessarily have to live in the same context, but they do need to be universally quanitfied over the context. This function takes care of renaming variables when checking for matches.