Checking that smart casts will not be broken by conversion

idea/testData/intentions/loopToCallChain/smartCastRequired2.kt

@@ -0,0 +1,11 @@
+// WITH_RUNTIME
+// IS_APPLICABLE: false
+fun foo(list: List<Any>, o: Any): Int? {
+    <caret>for (s in list) {
+        if (s is String && s.length > 0) {
+            val x = s.length * 2
+            return x
+        }
+    }
+    return null
+}