Pattern matching: work-around for smart cast target type instability #KT-14705 Fixed

idea/testData/checker/infos/SmartCastToEnum.kt

@@ -0,0 +1,14 @@
+package test2
+
+<info descr="null">enum</info> class En { A, B, С }
+
+fun main(args: Array<String>) {
+    val en2: Any? = En.A
+    if (en2 is En) {
+        when (<info descr="Smart cast to test2.En">en2</info>) {
+            En.A -> {}
+            En.B -> {}
+            En.С -> {}
+        }
+    }
+}

idea/tests/org/jetbrains/kotlin/checkers/PsiCheckerTestGenerated.java

@@ -917,6 +917,12 @@ public class PsiCheckerTestGenerated extends AbstractPsiCheckerTest {
             doTestWithInfos(fileName);
         }
 
+        @TestMetadata("SmartCastToEnum.kt")
+        public void testSmartCastToEnum() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/checker/infos/SmartCastToEnum.kt");
+            doTestWithInfos(fileName);
+        }
+
         @TestMetadata("SmartCasts.kt")
         public void testSmartCasts() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/checker/infos/SmartCasts.kt");