bareTvInRHSViolated :: [Type] -> Type -> [Type]
-- See Note [Verifying injectivity annotation]. This function implements second
-- check described there.
bareTvInRHSViolated pats rhs | isTyVarTy rhs
   = filter (not . isTyVarTy) pats
bareTvInRHSViolated :: [Type] -> Type -> [Type]
bareTvInRHSViolated pats rhs | isTyVarTy rhs
   = filter (not . isTyVarTy) pats
bareTvInRHSViolated pats rhs | isTyVarTy rhs
   = filter (not . isTyVarTy) pats