It's enough to have at least one good constraint.
Note that the whole algorithm can be a bit more general:
we could check also Out<T>, In<T> and verify that T has good only
lower constraint or upper constraint, but there are questions for
types like Inv<Out<T>>, where T should have lower and upper constraints
#KT-31514 Fixed
Follow-up of 9b3e17f0. There we decided to complete call if a type
variable from a return type has proper lower constraints, now we refine
this rule wrt `Nothing`-like constraints to avoid inferring type variables
to Nothing, which is quite useless
#KT-30370 Fixed
Mikhail Zarechenskiy