#1400. Add cascade operator test and more constants tests (#2545)

LanguageFeatures/Extension-types/dynamic_semantics_extension_type_A05_t04.dart

@@ -0,0 +1,33 @@
+// 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 Consider an extension type declaration DV named Name with
+/// representation name id and representation type R. Invocation of a
+/// non-redirecting generative extension type constructor proceeds as follows:
+/// A fresh, non-late, final variable v is created. An initializing formal
+/// this.id has the side-effect that it initializes v to the actual argument
+/// passed to this formal. An initializer list element of the form id = e or
+/// this.id = e is evaluated by evaluating e to an object o and binding v to o.
+/// During the execution of the constructor body, this and id are bound to the
+/// value of v. The value of the instance creation expression that gave rise to
+/// this constructor execution is the value of this.
+///
+/// @description Check evaluation of an initializer list with a cascade
+/// expressions
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=inline-class
+
+import '../../Utils/expect.dart';
+
+extension type ET1(List<int> id)  {
+  ET1.pair(int v1, int v2) : this.id = []
+    ..add(v1)
+    ..add(v2);
+}
+
+main() {
+  var et = ET1.pair(1, 2);
+  Expect.listEquals([1, 2], et);
+}

LanguageFeatures/Extension-types/syntax_A08_t05.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 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>
+/// ...
+/// Some errors can be detected immediately from the syntax:
+///
+/// A compile-time error occurs if the extension type declaration declares any
+/// instance variables, unless they are external
+///
+/// @description Checks that it is a compile-time error if an extension type
+/// declaration declares a non-static constant.
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=inline-class
+
+extension type ET(int _) {
+  const int x = 0;
+//^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
+}
+
+main() {
+  print(ET);
+}

LanguageFeatures/Extension-types/syntax_A10_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 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 extension types may have static final and constant
+/// members.
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=inline-class
+
+import "../../Utils/expect.dart";
+
+extension type ET1(int id) {
+  static final int answer = 42;
+  static const zero = 0;
+
+  const ET1.named() : id = zero;
+}
+
+extension type ET2(List<int> id) {
+  const ET2.named() : id = const [ET1.zero];
+}
+
+main() {
+  Expect.equals(42, ET1.answer);
+  Expect.identical(0, ET1.zero);
+  Expect.listEquals([0], ET2.named().id);
+  Expect.identical(const [0], const ET2.named().id);
+  Expect.identical(const [0], ET2.named().id);
+}