J2K: enum constants are non-nullable

j2k/src/org/jetbrains/jet/j2k/visitors/ExpressionVisitor.java

@@ -368,6 +368,9 @@ public class ExpressionVisitor extends StatementVisitor {
 
     private static boolean isResolvedToNotNull(PsiReference expression) {
         PsiElement target = expression.resolve();
+        if (target instanceof PsiEnumConstant) {
+            return true;
+        }
         if (target instanceof PsiModifierListOwner) {
             return ConverterUtil.isAnnotatedAsNotNull(((PsiModifierListOwner) target).getModifierList());
         }

j2k/tests/testData/ast/enum/class/enumConstantIsNotNull.jav

@@ -0,0 +1,7 @@
+enum E {
+  FOO;
+
+  void foo() {
+    FOO.toString();
+  }
+}

j2k/tests/testData/ast/enum/class/enumConstantIsNotNull.kt

@@ -0,0 +1,8 @@
+enum class E {
+FOO
+fun foo() : Unit {
+FOO.toString()
+}
+public fun name() : String { return "" }
+public fun order() : Int { return 0 }
+}