#461. A couple of NNBD nested nullable types tests added
diff --git a/LanguageFeatures/nnbd/syntax_A07_t05.dart b/LanguageFeatures/nnbd/syntax_A07_t05.dart
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+++ b/LanguageFeatures/nnbd/syntax_A07_t05.dart
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+/*
+ * 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 The grammar for types does not allow multiple successive ?
+ * operators on a type. That is, the grammar for types is nominally equivalent
+ * to:
+ * type' ::= functionType
+ * | qualified typeArguments?
+ * type ::= type' `?`?
+ *
+ * @description Check that it is no error to have multiple ? but not in the type
+ * declaration
+ * @author sgrekhov@unipro.ru
+ */
+// SharedOptions=--enable-experiment=non-nullable
+class A {}
+
+class C<T> {
+ T? t;
+}
+
+main() {
+ C<int?>(); // C.t has type int??, it's Ok
+ C<A?>(); // C.t has type A??, it's Ok
+}
diff --git a/LanguageFeatures/nnbd/syntax_A07_t06.dart b/LanguageFeatures/nnbd/syntax_A07_t06.dart
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+/*
+ * 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 The grammar for types does not allow multiple successive ?
+ * operators on a type. That is, the grammar for types is nominally equivalent
+ * to:
+ * type' ::= functionType
+ * | qualified typeArguments?
+ * type ::= type' `?`?
+ *
+ * @description Check that it is no error to have multiple ? but not in the type
+ * declaration. Test type aliases
+ * @author sgrekhov@unipro.ru
+ */
+// SharedOptions=--enable-experiment=non-nullable,nonfunction-type-aliases
+class A {}
+
+typedef AAlias1 = A?;
+typedef AAlias2 = AAlias1?;
+
+main() {
+ AAlias1 a1 = null;
+ AAlias2 a2 = null;
+}
