[FIR-TEST] Add new testdata generated after changes in previous commit

compiler/testData/diagnostics/tests/callableReference/kt31981.fir.kt

@@ -0,0 +1,23 @@
+// !LANGUAGE: +NewInference
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+import kotlin.reflect.KProperty1
+import kotlin.reflect.KMutableProperty1
+
+class Inv<T> {
+    val size: Int = 0
+}
+
+class DTO<T> {
+    val test: Inv<T>? = null
+    var q: Int = 0
+    operator fun <R> get(prop: KProperty1<*, R>): R = TODO()
+    operator fun <R> set(prop: KMutableProperty1<*, R>, value: R) { }
+}
+
+fun main(intDTO: DTO<Int>?) {
+    if (intDTO != null) {
+        intDTO[DTO<Int>::q] = intDTO[DTO<Int>::test]!!.size
+        intDTO[DTO<Int>::q] = intDTO[DTO<Int>::test]!!.size
+    }
+}