Let's say I have a class FooError that implements a bunch of different interfaces. I can't write a generic that uses FooError as a lower bound somehow, can I? Like I'd love to be able to do

inline fun <R> runFOrReturnFooError(f: () -> R): R = 
  if (someCondition) {
    f()
  } else {
    FooError()
  }

such that R is allowed to be any of the interfaces that FooError implements

Does

inline fun <R : FooError> runFOrReturnFooError(f: () -> R): R

work ?

Why not use a

Result

class?