Kotlin Contracts: assert instance on reified type parameter

I'm trying to write an assert function that checks if a given object is of a type T:

@UseExperimental(ExperimentalContracts::class)
inline fun <reified T> assertIsInstance(value: Any?) {
    contract {
        returns() implies (value is T)
    }

    Assertions.assertThat(value).isInstanceOf(T::class.java)
}

The function uses AssertJ to do the concrete assertion but I'm willing to let the compiler know that after its execution, the value is of type T so that a smartcast is possible. It seems like this does not work because:

Error in contract description: references to type parameters are forbidden in contracts

Is there another way to achieve this behavior? What's the issue here? Will this eventually be possible?

(Using Kotlin v1.3)

At some point there were some (deeply technical) concerns regarding support of such constructions in an IDE, but it's possible that this limitation will be relaxed in the future.