dart-lang#1959. Grammar tests added (dart-lang#2031)

Add grammar tests

LanguageFeatures/Class-modifiers/grammar_A01_t01.dart

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+// 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 The grammar is:
+///
+/// classDeclaration  ::= (classModifiers | mixinClassModifiers) 'class' typeIdentifier
+///                       typeParameters? superclass? interfaces?
+///                       '{' (metadata classMemberDeclaration)* '}'
+///                       | classModifiers 'class' mixinApplicationClass
+///
+/// classModifiers    ::= 'sealed'
+///                     | 'abstract'? ('base' | 'interface' | 'final')?
+///
+/// mixinClassModifiers ::= 'abstract'? 'base'? 'mixin'
+///
+/// mixinDeclaration  ::= 'base'? 'mixin' typeIdentifier typeParameters?
+///                       ('on' typeNotVoidList)? interfaces?
+///                       '{' (metadata classMemberDeclaration)* '}'
+///
+/// @description Check that it is a compile-time error if a built-in identifier
+/// `interface` is used as an identifier
+/// @author [email protected]
+
+// SharedOptions=--enable-experiment=class-modifiers
+
+class interface {}
+//    ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+main() {
+}

LanguageFeatures/Class-modifiers/grammar_A01_t02.dart

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+// 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 The grammar is:
+///
+/// classDeclaration  ::= (classModifiers | mixinClassModifiers) 'class' typeIdentifier
+///                       typeParameters? superclass? interfaces?
+///                       '{' (metadata classMemberDeclaration)* '}'
+///                       | classModifiers 'class' mixinApplicationClass
+///
+/// classModifiers    ::= 'sealed'
+///                     | 'abstract'? ('base' | 'interface' | 'final')?
+///
+/// mixinClassModifiers ::= 'abstract'? 'base'? 'mixin'
+///
+/// mixinDeclaration  ::= 'base'? 'mixin' typeIdentifier typeParameters?
+///                       ('on' typeNotVoidList)? interfaces?
+///                       '{' (metadata classMemberDeclaration)* '}'
+///
+/// @description Check that it is not an error to create a class named `base` or
+/// `sealed`
+/// @author [email protected]
+
+// SharedOptions=--enable-experiment=class-modifiers
+
+class base {}
+
+class sealed {}
+
+main() {
+  print(base);
+  print(sealed);
+}

LanguageFeatures/Class-modifiers/grammar_A01_t03.dart

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+// 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 The grammar is:
+///
+/// classDeclaration  ::= (classModifiers | mixinClassModifiers) 'class' typeIdentifier
+///                       typeParameters? superclass? interfaces?
+///                       '{' (metadata classMemberDeclaration)* '}'
+///                       | classModifiers 'class' mixinApplicationClass
+///
+/// classModifiers    ::= 'sealed'
+///                     | 'abstract'? ('base' | 'interface' | 'final')?
+///
+/// mixinClassModifiers ::= 'abstract'? 'base'? 'mixin'
+///
+/// mixinDeclaration  ::= 'base'? 'mixin' typeIdentifier typeParameters?
+///                       ('on' typeNotVoidList)? interfaces?
+///                       '{' (metadata classMemberDeclaration)* '}'
+///
+/// @description Check that it is not an error to declare a variable named
+/// `base`, `sealed` or `interface`
+/// @author [email protected]
+
+// SharedOptions=--enable-experiment=class-modifiers
+
+main() {
+  var base = 1;
+  var sealed = 2;
+  var interface = 3;
+
+  print(base);
+  print(sealed);
+  print(interface);
+}

LanguageFeatures/Class-modifiers/grammar_A02_t01.dart

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+// 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 The grammar is:
+///
+/// classDeclaration  ::= (classModifiers | mixinClassModifiers) 'class' typeIdentifier
+///                       typeParameters? superclass? interfaces?
+///                       '{' (metadata classMemberDeclaration)* '}'
+///                       | classModifiers 'class' mixinApplicationClass
+///
+/// classModifiers    ::= 'sealed'
+///                     | 'abstract'? ('base' | 'interface' | 'final')?
+///
+/// mixinClassModifiers ::= 'abstract'? 'base'? 'mixin'
+///
+/// mixinDeclaration  ::= 'base'? 'mixin' typeIdentifier typeParameters?
+///                       ('on' typeNotVoidList)? interfaces?
+///                       '{' (metadata classMemberDeclaration)* '}'
+///
+/// @description Check that it is a compile-time error if 'base', 'interface' or
+/// 'final' modifiers are placed before an `abstract` modifier
+/// @author [email protected]
+
+// SharedOptions=--enable-experiment=class-modifiers
+
+  base abstract class C1 {}
+//^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  interface abstract class C2 {}
+//^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  final abstract class C3 {}
+//      ^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+main() {
+  print(C1);
+  print(C2);
+  print(C3);
+}

LanguageFeatures/Class-modifiers/grammar_A02_t02.dart

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+// 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 The grammar is:
+///
+/// classDeclaration  ::= (classModifiers | mixinClassModifiers) 'class' typeIdentifier
+///                       typeParameters? superclass? interfaces?
+///                       '{' (metadata classMemberDeclaration)* '}'
+///                       | classModifiers 'class' mixinApplicationClass
+///
+/// classModifiers    ::= 'sealed'
+///                     | 'abstract'? ('base' | 'interface' | 'final')?
+///
+/// mixinClassModifiers ::= 'abstract'? 'base'? 'mixin'
+///
+/// mixinDeclaration  ::= 'base'? 'mixin' typeIdentifier typeParameters?
+///                       ('on' typeNotVoidList)? interfaces?
+///                       '{' (metadata classMemberDeclaration)* '}'
+///
+/// @description Check that it is a compile-time error if 'mixin', 'base', or
+/// `abstract` modifiers goes in a wrong order
+/// @author [email protected]
+
+// SharedOptions=--enable-experiment=class-modifiers
+
+  base abstract mixin class C1 {}
+//     ^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  base mixin abstract class C2 {}
+//           ^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  mixin base abstract class C3 {}
+//      ^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  mixin abstract base class C4 {}
+//      ^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  abstract mixin base class C5 {}
+//               ^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  mixin abstract class C6 {}
+//      ^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+  mixin base class C7 {}
+//      ^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+
+main() {
+  print(C1);
+  print(C2);
+  print(C3);
+  print(C4);
+  print(C5);
+  print(C6);
+  print(C7);
+}