From fa686fc48781b433304b7028f2da8bc0f1fb40a5 Mon Sep 17 00:00:00 2001
From: "Sergey G. Grekhov" <sgrekhov22@gmail.com>
Date: Fri, 31 Mar 2023 13:58:31 +0300
Subject: [PATCH] #1401. Additional test for the rest element of a list pattern
 (#1980)

---
 LanguageFeatures/Patterns/list_A04_t07.dart | 102 ++++++++++++++++++++
 1 file changed, 102 insertions(+)
 create mode 100644 LanguageFeatures/Patterns/list_A04_t07.dart

diff --git a/LanguageFeatures/Patterns/list_A04_t07.dart b/LanguageFeatures/Patterns/list_A04_t07.dart
new file mode 100644
index 0000000000..71914d16db
--- /dev/null
+++ b/LanguageFeatures/Patterns/list_A04_t07.dart
@@ -0,0 +1,102 @@
+// Copyright (c) 2022, 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
+/// listPattern         ::= typeArguments? '[' listPatternElements? ']'
+/// listPatternElements ::= listPatternElement ( ',' listPatternElement )* ','?
+/// listPatternElement  ::= pattern | restPattern
+/// restPattern         ::= '...' pattern?
+///
+/// A list pattern may contain a rest element which allows matching lists of
+/// arbitrary lengths. If a rest element is present and has a subpattern, all of
+/// the elements not matched by other subpatterns are collected into a new list
+/// and that list is matched against the rest subpattern.
+///
+/// var [a, b, ...rest, c, d] = [1, 2, 3, 4, 5, 6, 7];
+/// print('$a $b $rest $c $d'); // Prints "1 2 [3, 4, 5] 6 7".
+///
+/// @description Check that if a rest element is present and has a subpattern,
+/// all of the elements not matched by other subpatterns are collected into a
+/// new list and that list is matched against the rest subpattern. Test rest
+/// pattern with a list subpattern
+/// @author sgrekhov22@gmail.com
+
+// SharedOptions=--enable-experiment=patterns
+
+import "../../Utils/expect.dart";
+
+String test1(List list) {
+  return switch (list) {
+    <int>[1, 2, 3, 4, ...[5]] => "[1, 2, 3, 4, ...[5]]",
+    [2, ...[3], 5, 6] => "[2, ...[3], 5, 6]",
+    <int>[... /* comment */[..., 5], 6, 7, 8] => "[...[..., 5], 6, 7, 8]",
+    _ => "default"
+  };
+}
+
+String test2(List list) {
+  switch (list) {
+    case <int>[1, 2, 3, 4, ...[5]]:
+      return "[1, 2, 3, 4, ...[5]]";
+    case [2, ...[3], 5, 6]:
+      return "[2, ...[3], 5, 6]";
+    case <int>[... /* comment */[..., 5], 6, 7, 8]:
+      return "[...[..., 5], 6, 7, 8]";
+    default:
+      return "default";
+  }
+}
+
+String test3(List list) {
+  if (list case <int>[1, 2, 3, 4, ...[5]]) {
+    return "[1, 2, 3, 4, ...[5]]";
+  }
+  if (list case [2, ...[3], 5, 6]) {
+    return "[2, ...[3], 5, 6]";
+  }
+  if (list case <int>[... /* comment */[..., 5], 6, 7, 8]) {
+    return "[...[..., 5], 6, 7, 8]";
+  }
+  return "default";
+}
+
+main() {
+  var <int>[a1, b1, ...[c1, ...]] = [1, 2, 3, 4, 5];
+  Expect.equals(1, a1);
+  Expect.equals(2, b1);
+  Expect.equals(3, c1);
+
+  final [a2, ...[c2, d2], b2] = [2, 3, 4, 5];
+  Expect.equals(2, a2);
+  Expect.equals(5, b2);
+  Expect.equals(3, c2);
+  Expect.equals(4, d2);
+
+  var [... /* comment */[..., c3], a3, b3] = [1, 2, 3, 4, 5];
+  Expect.equals(4, a3);
+  Expect.equals(5, b3);
+  Expect.equals(3, c3);
+
+  Expect.equals("[1, 2, 3, 4, ...[5]]", test1(<int>[1, 2, 3, 4, 5]));
+  Expect.equals("[2, ...[3], 5, 6]", test1([2, 3, 5, 6]));
+  Expect.equals("[...[..., 5], 6, 7, 8]", test1(<int>[3, 4, 5, 6, 7, 8]));
+  Expect.equals("default", test1([1, 2]));
+  Expect.equals("default", test1([1, 2, 3, 4, 5, 6]));
+  Expect.equals("default", test1([2, 3, 4, 5, 6]));
+  Expect.equals("default", test1(<int>[1, 2, 3, 4, 5, 6]));
+  Expect.equals("[1, 2, 3, 4, ...[5]]", test2(<int>[1, 2, 3, 4, 5]));
+  Expect.equals("[2, ...[3], 5, 6]", test2([2, 3, 5, 6]));
+  Expect.equals("[...[..., 5], 6, 7, 8]", test2(<int>[3, 4, 5, 6, 7, 8]));
+  Expect.equals("default", test2([1, 2]));
+  Expect.equals("default", test2([1, 2, 3, 4, 5, 6]));
+  Expect.equals("default", test2([2, 3, 4, 5, 6]));
+  Expect.equals("default", test2(<int>[1, 2, 3, 4, 5, 6]));
+  Expect.equals("[1, 2, 3, 4, ...[5]]", test3(<int>[1, 2, 3, 4, 5]));
+  Expect.equals("[2, ...[3], 5, 6]", test3([2, 3, 5, 6]));
+  Expect.equals("[...[..., 5], 6, 7, 8]", test3(<int>[3, 4, 5, 6, 7, 8]));
+  Expect.equals("default", test3([1, 2]));
+  Expect.equals("default", test3([1, 2, 3, 4, 5, 6]));
+  Expect.equals("default", test3([2, 3, 4, 5, 6]));
+  Expect.equals("default", test3(<int>[1, 2, 3, 4, 5, 6]));
+}