kotlin-fork/compiler/testData/diagnostics/tests/functionLiterals/kt51317.kt

val f: (String.() -> String)? = null

fun box(): String {
    val g = when {
        f != null -> <!DEBUG_INFO_SMARTCAST!>f<!>
        else -> {
            { this + "K" }
        }
    }
    return g("O")
}