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

compiler/testData/diagnostics/tests/regressions/kt235.fir.kt

@@ -0,0 +1,49 @@
+//KT-235 Illegal assignment return type
+
+package kt235
+
+fun main() {
+    val array = MyArray()
+    val f: () -> String = {
+        array[2] = 23 //error: Type mismatch: inferred type is Int (!!!) but String was expected
+    }
+    val g: () -> String = {
+        var x = 1
+        x += 2  //no error, but it should be here
+    }
+    val h: () -> String = {
+        var x = 1
+        x = 2  //the same
+    }
+    val array1 = MyArray1()
+    val i: () -> String = {
+        array1[2] = 23
+    }
+
+    val fi: () -> String = {
+        array[2] = 23
+    }
+    val gi: () -> String = {
+        var x = 1
+        x += 21
+    }
+
+    var m: MyNumber = MyNumber()
+    val a: () -> MyNumber = {
+        m++
+    }
+}
+
+class MyArray() {
+    operator fun get(i: Int): Int = 1
+    operator fun set(i: Int, value: Int): Int = 1
+}
+
+class MyArray1() {
+    operator fun get(i: Int): Int = 1
+    operator fun set(i: Int, value: Int) {}
+}
+
+class MyNumber() {
+    operator fun inc(): MyNumber = MyNumber()
+}