#2142. Add syntax tests (#2148)

Add syntax tests for extension type declarations.

LanguageFeatures/Extension-types/extension_type_lib.dart

@@ -0,0 +1,15 @@
+// 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.
+
+/// @description Helper library for testing extension types
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=inline-class
+
+library extension_type_lib;
+
+int x = 42;
+
+extension type _PrivateExtensionType(int id) {
+}

LanguageFeatures/Extension-types/syntax_A01_t01.dart

@@ -0,0 +1,36 @@
+// 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>
+///
+/// The token `type` is not made a built-in identifier: the built-in identifier
+/// extension that occurs right before type serves to disambiguate the extension
+/// type declaration with a fixed lookahead.
+///
+/// @description Checks that it is not an error to declare a class named `type`
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=inline-class
+
+class type {
+}
+
+main() {
+  type();
+}

LanguageFeatures/Extension-types/syntax_A01_t02.dart

@@ -0,0 +1,38 @@
+// 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>
+///
+/// The token `type` is not made a built-in identifier: the built-in identifier
+/// extension that occurs right before type serves to disambiguate the extension
+/// type declaration with a fixed lookahead.
+///
+/// @description Checks that it is not an error to declare a mixin named `type`
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=inline-class
+
+mixin type on Object {
+}
+
+class IA = Object with type;
+
+main() {
+  IA();
+}

LanguageFeatures/Extension-types/syntax_A01_t03.dart

@@ -0,0 +1,36 @@
+// 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>
+///
+/// The token `type` is not made a built-in identifier: the built-in identifier
+/// extension that occurs right before type serves to disambiguate the extension
+/// type declaration with a fixed lookahead.
+///
+/// @description Checks that it is not an error to import a library with
+/// import prefix `type`
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=inline-class
+
+import "extension_type_lib.dart" as type;
+
+main() {
+  print(type.x);
+}

LanguageFeatures/Extension-types/syntax_A01_t04.dart

@@ -0,0 +1,37 @@
+// 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>
+///
+/// The token `type` is not made a built-in identifier: the built-in identifier
+/// extension that occurs right before type serves to disambiguate the extension
+/// type declaration with a fixed lookahead.
+///
+/// @description Checks that it is not an error to declare a type alias named
+/// `type`
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=inline-class
+
+typedef type = String;
+
+main() {
+  type s = "type";
+  s.substring(1);
+}

LanguageFeatures/Extension-types/syntax_A02_t01.dart

@@ -0,0 +1,36 @@
+// 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
+/// declaration doesn't contain `typeIdentifier`
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=inline-class
+
+extension type (int id) {
+//             ^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+main() {
+
+}

LanguageFeatures/Extension-types/syntax_A02_t02.dart

@@ -0,0 +1,34 @@
+// 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 to refer an extension
+/// type with the `typeIdentifier` started with `_` outside of the library where
+/// it is defined
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=inline-class
+
+main() {
+  print(_PrivateExtensionType);
+//      ^^^^^^^^^^^^^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}

LanguageFeatures/Extension-types/syntax_A03_t01.dart

@@ -0,0 +1,38 @@
+// 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 an extension type declaration may have type
+/// parameters
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=inline-class
+
+import "../../Utils/expect.dart";
+
+extension type ET<T>(T id) {}
+
+main() {
+  ET<int> et1 = ET<int>(42);
+  Expect.equals(42, et1.id);
+
+  ET<String> et2 = ET<String>.new("42");
+  Expect.equals("42", et2.id);
+}

LanguageFeatures/Extension-types/syntax_A04_t01.dart

@@ -0,0 +1,36 @@
+// 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
+/// declaration doesn't contain `representationDeclaration`
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=inline-class
+
+extension type ET {
+//             ^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+main() {
+  print(ET);
+}

LanguageFeatures/Extension-types/syntax_A04_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 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 a `representationDeclaration` may have form
+/// `identifier`.`identifier`...
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=inline-class
+
+import "../../Utils/expect.dart";
+
+extension type ET.et(int id) {}
+
+main() {
+  ET et = ET.et(42);
+  Expect.equals(42, et.id);
+}

LanguageFeatures/Extension-types/syntax_A04_t03.dart

@@ -0,0 +1,38 @@
+// 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 a `representationDeclaration` may have form
+/// `identifier`.new
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=inline-class
+
+import "../../Utils/expect.dart";
+
+extension type ET.new(int id) {}
+
+main() {
+  ET et1 = ET(1);
+  Expect.equals(1, et1.id);
+
+  ET et2 = ET.new(2);
+  Expect.equals(2, et2.id);
+}