Error found:
in module ContravariantInstance1
at tests/purs/failing/ContravariantInstance1.purs:9:1 - 9:35 (line 9, column 1 - line 9, column 35)

  One or more type variables are in positions that prevent Contravariant from being derived.
  To derive this class, make sure that these variables are only used as the final arguments to type constructors, that their variance matches the variance of Contravariant, and that those type constructors themselves have instances of Data.Functor.Functor, Data.Bifunctor.Bifunctor, Data.Functor.Contravariant.Contravariant, or Data.Profunctor.Profunctor.

  tests/purs/failing/ContravariantInstance1.purs:
      6 
      7 newtype Test a = Test (Predicate (Predicate a))
      8 


See https://github.com/purescript/documentation/blob/master/errors/CannotDeriveInvalidConstructorArg.md for more information,
or to contribute content related to this error.