Minor. Add more tests

compiler/testData/codegen/box/inlineClasses/kt25750Generic.kt

@@ -0,0 +1,26 @@
+// WITH_STDLIB
+// WORKS_WHEN_VALUE_CLASS
+// LANGUAGE: +ValueClasses, +GenericInlineClassParameter
+
+import kotlin.reflect.KMutableProperty0
+import kotlin.reflect.KProperty
+
+operator fun <R> KMutableProperty0<R>.setValue(host: Any?, property: KProperty<*>, value: R) = set(value)
+operator fun <R> KMutableProperty0<R>.getValue(host: Any?, property: KProperty<*>): R = get()
+
+OPTIONAL_JVM_INLINE_ANNOTATION
+value class Foo<T: Int>(val i: T)
+
+var f = Foo(4)
+
+fun <T: Int> modify(ref: KMutableProperty0<Foo<T>>) {
+    var a by ref
+    a = Foo(1) as Foo<T>
+}
+
+fun box(): String {
+    modify(::f)
+    if (f.i != 1) throw AssertionError()
+
+    return "OK"
+}