KT-4008 'Replace if with when' is available but does not work

idea/testData/intentions/branched/ifWhen/whenToIf/whenWithoutElse.kt

@@ -0,0 +1,9 @@
+fun test(n: Int) {
+    val s = "test"
+    <caret>when (n) {
+        0 -> s = "zero"
+        1 -> s = "one"
+        2 -> s = "two"
+    }
+    return s
+}