diff --git a/LanguageFeatures/nnbd/Null_promotion_A01_t01.dart b/LanguageFeatures/nnbd/Null_promotion_A01_t01.dart
index 59273e0..c231aa2 100644
--- a/LanguageFeatures/nnbd/Null_promotion_A01_t01.dart
+++ b/LanguageFeatures/nnbd/Null_promotion_A01_t01.dart
@@ -9,51 +9,52 @@
  * continuation, and to [NonNull(T)] in the [false] continuation.
  *
  * @description Check that [e] is promoted to [Null] in the [true] condition.
+ * Test [e == null] expression
  * @author iarkh@unipro.ru
+ * @author sgrekhov@unipro.ru
  */
-// SharedOptions=--enable-experiment=non-nullable,nonfunction-type-aliases
+// SharedOptions=--enable-experiment=non-nullable
 
-import "../../Utils/expect.dart";
-
-class A {}
-class B<T> {}
-
-typedef AA = A;
-typedef AAA = A?;
-
-void checkme(var x, var expectedType) {
-  Expect.equals(Null, x.runtimeType);
-  Expect.isTrue(x == null);
-  Expect.isTrue(x is Null);
-  Expect.isFalse(x is NonNull(expectedType));
+class A {
+  foo() {}
 }
 
+class B<T> {
+  bar() {}
+}
+
+dynamic init() => null;
+
 main() {
-  checkme(null, Null);
+  A? a = init();
+  if (a == null) {
+    a.foo();
+//    ^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  }
 
-  A ? a = null;
-  checkme(a, A);
+  B? b1 = init();
+  if (b1 == null) {
+    b1.bar();
+//     ^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  }
 
-  B? b1 = null;
-  checkme(b1, B);
+  B<int>? b2 = init();
+  if (b2 == null) {
+    b2.bar();
+//     ^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  }
 
-  B<int> ? b2 = null;
-  checkme(b2, B);
-
-  dynamic ? d = null;
-  checkme(d, dynamic);
-
-  Object ? o = null;
-  checkme(o, Object);
-
-  Null n = null;
-  checkme(n, Null);
-
-  AA ? aa = null;
-  checkme(aa, AA);
-  checkme(aa, A);
-
-  AAA aaa = null;
-  checkme(aaa, AAA);
-  checkme(aaa, A);
+  int? i = init();
+  if (i == null) {
+    i.isOdd;
+//    ^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  }
 }
diff --git a/LanguageFeatures/nnbd/Null_promotion_A01_t02.dart b/LanguageFeatures/nnbd/Null_promotion_A01_t02.dart
index b8a48b2..4d8bbe9 100644
--- a/LanguageFeatures/nnbd/Null_promotion_A01_t02.dart
+++ b/LanguageFeatures/nnbd/Null_promotion_A01_t02.dart
@@ -8,50 +8,52 @@
  * [e] has static type [T] promotes the type of [e] to [Null] in the [true]
  * continuation, and to [NonNull(T)] in the [false] continuation.
  *
- * @description Check that [e] is promoted to [NonNull(T)] in the [false]
- * condition.
- * @author iarkh@unipro.ru
+ * @description Check that [e] is promoted to [Null] in the [true] condition.
+ * Test [e is Null] expression
+ * @author sgrekhov@unipro.ru
  */
-// SharedOptions=--enable-experiment=non-nullable,nonfunction-type-aliases
+// SharedOptions=--enable-experiment=non-nullable
 
-import "../../Utils/expect.dart";
-
-class A {}
-class B<T> {}
-
-typedef AA = A;
-typedef AAA = A?;
-
-void checkme(var x, var expectedType) {
-  Expect.isFalse(x == null);
-  Expect.isFalse(x is Null);
-  Expect.isTrue(x is NonNull(expectedType));
-  Expect.isTrue(x is NonNull(Object));
+class A {
+  foo() {}
 }
 
+class B<T> {
+  bar() {}
+}
+
+dynamic init() => null;
+
 main() {
-  A a1 = A();
-  checkme(a1, A);
+  A? a = init();
+  if (a is Null) {
+    a.foo();
+//    ^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  }
 
-  A? a2 = A();
-  checkme(a2, A);
+  B? b1 = init();
+  if (b1 is null) {
+    b1.bar();
+//     ^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  }
 
-  B b1 = B();
-  checkme(b1, B);
+  B<int>? b2 = init();
+  if (b2 is Null) {
+    b2.bar();
+//     ^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  }
 
-  B? b2 = B();
-  checkme(b2, B);
-
-  B<int> b3 = B<int>();
-  checkme(b3, B);
-
-  B<int> ? b4 = B<int>();
-  checkme(b4, B);
-
-  dynamic d = 12345;
-  checkme(d, int);
-  checkme(d, dynamic);
-
-  Object o = "14";
-  checkme(o, String);
+  int? i = init();
+  if (i is Null) {
+    i.isOdd;
+//    ^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  }
 }
diff --git a/LanguageFeatures/nnbd/Null_promotion_A01_t03.dart b/LanguageFeatures/nnbd/Null_promotion_A01_t03.dart
new file mode 100644
index 0000000..cda52f2
--- /dev/null
+++ b/LanguageFeatures/nnbd/Null_promotion_A01_t03.dart
@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
+ * for details. All rights reserved. Use of this source code is governed by a
+ * BSD-style license that can be found in the LICENSE file.
+ */
+/**
+ * @assertion A check of the form [e == null] or of the form [e is Null] where
+ * [e] has static type [T] promotes the type of [e] to [Null] in the [true]
+ * continuation, and to [NonNull(T)] in the [false] continuation.
+ *
+ * @description Check that [e] is promoted to [Null] in the [true] condition.
+ * Test type aliases
+ * @author sgrekhov@unipro.ru
+ */
+// SharedOptions=--enable-experiment=non-nullable,nonfunction-type-aliases
+
+class A {
+  foo() {}
+}
+
+typedef AAlias1 = A?
+typedef AAlias2 = AAlias1?
+
+dynamic init() => null;
+
+main() {
+  AAlias1 a1 = init();
+  if (a1 is Null) {
+    a1.foo();
+//     ^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  }
+
+  if (a1 == null) {
+    a1.foo();
+//     ^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  }
+
+  AAlias2? a2 = init();
+  if (a2 is Null) {
+    a2.foo();
+//    ^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  }
+
+  if (a2 == null) {
+    a2.foo();
+//     ^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  }
+}
diff --git a/LanguageFeatures/nnbd/Null_promotion_A01_t04.dart b/LanguageFeatures/nnbd/Null_promotion_A01_t04.dart
new file mode 100644
index 0000000..daa752b
--- /dev/null
+++ b/LanguageFeatures/nnbd/Null_promotion_A01_t04.dart
@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
+ * for details. All rights reserved. Use of this source code is governed by a
+ * BSD-style license that can be found in the LICENSE file.
+ */
+/**
+ * @assertion A check of the form [e == null] or of the form [e is Null] where
+ * [e] has static type [T] promotes the type of [e] to [Null] in the [true]
+ * continuation, and to [NonNull(T)] in the [false] continuation.
+ *
+ * @description Check that [e] is promoted to [Null] in the [true] condition.
+ * Test pre-NNBD legacy types
+ * @author sgrekhov@unipro.ru
+ */
+// SharedOptions=--enable-experiment=non-nullable
+import "legacy_library_lib.dart";
+
+dynamic init() => null;
+
+main() {
+  A a = init();
+  if (a is Null) {
+    a.foo();
+//    ^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  }
+
+  if (a == null) {
+    a.foo();
+//    ^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  }
+}
diff --git a/LanguageFeatures/nnbd/Null_promotion_A01_t05.dart b/LanguageFeatures/nnbd/Null_promotion_A01_t05.dart
new file mode 100644
index 0000000..d020f99
--- /dev/null
+++ b/LanguageFeatures/nnbd/Null_promotion_A01_t05.dart
@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
+ * for details. All rights reserved. Use of this source code is governed by a
+ * BSD-style license that can be found in the LICENSE file.
+ */
+/**
+ * @assertion A check of the form [e == null] or of the form [e is Null] where
+ * [e] has static type [T] promotes the type of [e] to [Null] in the [true]
+ * continuation, and to [NonNull(T)] in the [false] continuation.
+ *
+ * @description Check that [e] is promoted to [Null] in the [true] condition.
+ * Test pre-NNBD legacy types and type aliases
+ * @author sgrekhov@unipro.ru
+ */
+// SharedOptions=--enable-experiment=non-nullable,nonfunction-type-aliases
+import "legacy_library_lib.dart";
+import "legacy_library_aliases_lib.dart" as legacy;
+
+dynamic init() => null;
+
+typedef AAlias = A;
+
+main() {
+  AAlias a1 = init();
+  if (a1 is Null) {
+    a1.foo();
+//     ^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  }
+
+  if (a1 == null) {
+    a1.foo();
+//     ^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  }
+
+  legacy.AAlias a2 = init();
+  if (a2 is Null) {
+    a2.bar();
+//     ^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  }
+
+  if (a2 == null) {
+    a2.bar();
+//     ^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+  }
+}
diff --git a/LanguageFeatures/nnbd/legacy_library_aliases_lib.dart b/LanguageFeatures/nnbd/legacy_library_aliases_lib.dart
index 51f66e3..b5edb3c 100644
--- a/LanguageFeatures/nnbd/legacy_library_aliases_lib.dart
+++ b/LanguageFeatures/nnbd/legacy_library_aliases_lib.dart
@@ -11,6 +11,7 @@
 library legacy_library_aliases_lib;
 
 class A {
+  void bar() {}
 }
 
 typedef AAlias = A;
diff --git a/LanguageFeatures/nnbd/legacy_library_lib.dart b/LanguageFeatures/nnbd/legacy_library_lib.dart
index eb80704..3b6a5ee 100644
--- a/LanguageFeatures/nnbd/legacy_library_lib.dart
+++ b/LanguageFeatures/nnbd/legacy_library_lib.dart
@@ -11,6 +11,7 @@
 library legacy_library_lib;
 
 class A {
+  void foo() {}
 }
 
 class C<X extends A> {