Calling Kotlin methods from R: invokeMethod returns "java.lang.IllegalStateException: receiverKlass.java.classLoader must not be null"

[floidgilbert]

invokeMethod fails in Kotlin. This is a reported bug: KT-22414. There is a workaround: add the reference to the Kotlin bindings as in this example.

engine %@% "class A {fun f(): Int {return 8}}"
engine %@% "val a = A()"
engine %@% "a.f()"

# This line fails
engine$invokeMethod("a", "f")

# After adding the reference to bindings, the call works.
engine %@% "jsr223Bindings[\"a\"] = a"
engine$invokeMethod("a", "f")