failed to attach sorts to rule: f(?b) -> ?a

failed to attach sorts to rule: f(?b) -> f(?c)

failed to attach sorts to rule: f(?c) -> f(?b)

failed to attach sorts to rule: f(?c) -> ?d

failed to attach sorts to rule: ?b -> ?e

failed to attach sorts to rule: ?c -> ?e'

failed to attach sorts to rule: f(?e) -> ?a

failed to attach sorts to rule: f(?e') -> ?d