#1400. Add tests for external members, covariant parameters, nullable…

… supertypes (#2225)

Add tests for external members, covariant parameters, nullable supertypes. Note that A10_t02 and A12_t01 intentionally have a syntax error (a superinterface of the form `T?`).

LanguageFeatures/Extension-types/static_analysis_extension_types_A27_t01.dart

@@ -39,9 +39,17 @@ extension type ET4<T>(T id) {
 // [cfe] unspecified
 }
 
+extension type ET5(int id) {
+  int operator +(int other);
+//^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
 main() {
   print(ET1);
   print(ET2);
   print(ET3);
   print(ET4);
+  print(ET5);
 }

LanguageFeatures/Extension-types/static_analysis_extension_types_A28_t01.dart

@@ -0,0 +1,40 @@
+// Copyright (c) 2023, 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 It is not an error for an extension type member to have the
+/// modifier external
+///
+/// @description Checks that it is not an error for an extension type member to
+/// have the modifier `external`
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=inline-class
+
+extension type ET1(int id) {
+  external int m;
+}
+
+extension type ET2<T>(T id) {
+  external T get getter;
+}
+
+extension type ET3(int id) {
+  external void setter(int x);
+}
+
+extension type ET4<T extends num>(T id) {
+  external void method();
+}
+
+extension type ET5(int id) {
+  external int operator +(int other);
+}
+
+main() {
+  print(ET1);
+  print(ET2);
+  print(ET3);
+  print(ET4);
+  print(ET5);
+}

LanguageFeatures/Extension-types/static_analysis_extension_types_A28_t02.dart

@@ -0,0 +1,35 @@
+// Copyright (c) 2023, 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 It is not an error for an extension type member to have the
+/// modifier external
+///
+/// @description Checks that it is not an error for an extension type static
+/// member to have the modifier `external`
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=inline-class
+
+extension type ET1(int id) {
+  external static int m;
+}
+
+extension type ET2<T>(T id) {
+  external static T get getter;
+}
+
+extension type ET3(int id) {
+  external static void setter(int x);
+}
+
+extension type ET4<T extends num>(T id) {
+  external static void method();
+}
+
+main() {
+  print(ET1);
+  print(ET2);
+  print(ET3);
+  print(ET4);
+}

LanguageFeatures/Extension-types/static_analysis_extension_types_A29_t01.dart

@@ -0,0 +1,40 @@
+// Copyright (c) 2023, 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 It is a compile-time error if the modifier covariant occurs in
+/// the declaration of a formal parameter of a function which is not an instance
+/// method, an instance setter, or an operator.
+///
+/// @description Checks that it is a compile-time error if an extension type
+/// member has a member with a covariant formal parameter
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=inline-class
+
+extension type ET1(num id) {
+  void method(covariant int i) {}
+//            ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+extension type ET2<T extends num>(T id) {
+  void setter(covariant int x) {}
+//            ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+extension type ET3(num id) {
+  int operator +(covariant int other) => other + id.floor();
+//               ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+main() {
+  print(ET1);
+  print(ET2);
+  print(ET3);
+}

LanguageFeatures/Extension-types/syntax_A10_t02.dart

@@ -0,0 +1,41 @@
+// Copyright (c) 2023, 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 rule for <extensionTypeDeclaration> is added to the grammar,
+/// along with some rules for elements used in extension type declarations:
+///
+/// <extensionTypeDeclaration> ::=
+///   'extension' 'type' 'const'? <typeIdentifier> <typeParameters>?
+///   <representationDeclaration> <interfaces>?
+///   '{'
+///     (<metadata> <extensionTypeMemberDeclaration>)*
+///   '}'
+///
+/// <representationDeclaration> ::=
+///   ('.' <identifierOrNew>)? '(' <metadata> <type> <identifier> ')'
+///
+/// <identifierOrNew> ::= <identifier> | 'new'
+///
+/// <extensionTypeMemberDeclaration> ::= <classMemberDefinition>
+/// ...
+/// There are no special rules for static members in extension types. They can
+/// be declared and called or torn off as usual, e.g.,
+/// AnExtensionType.myStaticMethod(42)
+///
+/// @description Checks that it is a compile-time error if an extension type
+/// declares a static operator
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=inline-class
+
+extension type ET(int id) {
+  static int operator +(int other) => id + other;
+//^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+main() {
+  print(ET);
+}

LanguageFeatures/Extension-types/syntax_A12_t01.dart

@@ -0,0 +1,55 @@
+// Copyright (c) 2023, 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 rule for <extensionTypeDeclaration> is added to the grammar,
+/// along with some rules for elements used in extension type declarations:
+///
+/// <extensionTypeDeclaration> ::=
+///   'extension' 'type' 'const'? <typeIdentifier> <typeParameters>?
+///   <representationDeclaration> <interfaces>?
+///   '{'
+///     (<metadata> <extensionTypeMemberDeclaration>)*
+///   '}'
+///
+/// <representationDeclaration> ::=
+///   ('.' <identifierOrNew>)? '(' <metadata> <type> <identifier> ')'
+///
+/// <identifierOrNew> ::= <identifier> | 'new'
+///
+/// <extensionTypeMemberDeclaration> ::= <classMemberDefinition>
+///
+/// @description Checks that it is a compile-time error if an extension type
+/// has a nullable type as a superinterface
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=inline-class
+
+typedef NullableInt = int?;
+
+extension type ET1(int id) implements int? {}
+//                                       ^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+extension type ET2(int? id) implements int? {}
+//                                        ^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+extension type ET3(int id) implements NullableInt {}
+//                                    ^^^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+extension type ET4(int? id) implements NullableInt {}
+//                                     ^^^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+main() {
+  print(ET1);
+  print(ET2);
+  print(ET3);
+  print(ET4);
+}