FILE: kt55722.kt
    public abstract interface A<T> : R|kotlin/Any| {
        public open fun foo(x: R|T?|): R|kotlin/Unit| {
        }

    }
    public abstract interface B<F> : R|A<F>| {
        public abstract override fun foo(x: R|F?|): R|kotlin/Unit|

    }
    public final fun <T> bar(x: R|A<in T>|): R|kotlin/Unit| {
        when () {
            (R|<local>/x| is R|B<in T>|) ->  {
                R|<local>/x|.R|SubstitutionOverride</B.foo: R|kotlin/Unit|>|(Null(null))
            }
        }

    }