bad_instance2.m:012: In instance declaration for `foo(bad_instance2.bar(T),
bad_instance2.m:012:   U)':
bad_instance2.m:012:   the second instance type `U' is a type variable; it
bad_instance2.m:012:   should be a type constructor applied to zero or more
bad_instance2.m:012:   type variables.
bad_instance2.m:016: In instance declaration for `foo(bad_instance2.bar(T),
bad_instance2.m:016:   T)':
bad_instance2.m:016:   the second instance type `T' is a type variable; it
bad_instance2.m:016:   should be a type constructor applied to zero or more
bad_instance2.m:016:   type variables.
For more information, recompile with `-E'.