[wildcard-variables] Test non-binding behaviour with top-level declarations.

Added a little section for late wildcard variables too.

This CL tests mixing top-level wildcard declarations with local wildcard declarations and the non-shadowing, non-binding behaviour.

Bug: https://github.com/dart-lang/sdk/issues/55652
Change-Id: I72e7cfb1b2d80a3934af355579c36252881cf3fb
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/367241
Reviewed-by: Lasse Nielsen <lrn@google.com>
Commit-Queue: Kallen Tu <kallentu@google.com>

tests/language/wildcard_variables/multiple/local_declaration_local_test.dart

@@ -16,4 +16,10 @@ void main() {
 
   int _;
   final _;
+
+  late int _;
+  late int _ = 2;
+
+  late final int _;
+  late final int _ = 2;
 }

tests/language/wildcard_variables/non_binding/class_members_test.dart

@@ -0,0 +1,50 @@
+// Copyright (c) 2024, 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.
+
+// Test the interactions between a wildcard class members, which are binding,
+// with local non-binding wildcard variables.
+
+// SharedOptions=--enable-experiment=wildcard-variables
+
+import 'package:expect/expect.dart';
+
+void main() {
+  InstanceMember().member();
+  StaticMember().member();
+}
+
+class InstanceMember {
+  var _ = 2;
+
+  void member<_, _>() {
+    int _ = _;
+    int _ = 2;
+    const _ = 2;
+    int _() => 2;
+    _ = 3;
+    Expect.equals(3, _);
+
+    int _() => 2;
+
+    int foo<_>([int _ = 5]) => _;
+    Expect.equals(3, foo());
+  }
+}
+
+class StaticMember {
+  static const _ = 2;
+
+  void member<_, _>() {
+    int _ = _;
+    int _ = 2;
+    const _ = 2;
+    const _ = _ - 1;
+    int _() => 2;
+    _ = 3;
+    Expect.equals(3, _);
+
+    int foo<_>([int _ = _ + 1]) => _;
+    Expect.equals(3, foo());
+  }
+}

tests/language/wildcard_variables/non_binding/top_level_function_test.dart

@@ -0,0 +1,28 @@
+// Copyright (c) 2024, 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.
+
+// Test the interactions between a wildcard top-level function, which is
+// binding, with local non-binding wildcard variables.
+
+// SharedOptions=--enable-experiment=wildcard-variables
+
+import 'package:expect/expect.dart';
+
+int _(int _) => 2;
+
+void main() {
+  int _ = 1;
+  const _ = 1;
+  int _() => 1;
+  Expect.equals(2, _(1));
+}
+
+class Clas<_> {
+  void member<_>() {
+    int _ = 1;
+    const _ = 1;
+    int _() => 1;
+    Expect.equals(2, _(1));
+  }
+}

tests/language/wildcard_variables/non_binding/top_level_typedef_test.dart

@@ -0,0 +1,36 @@
+// Copyright (c) 2024, 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.
+
+// Test the interactions between a wildcard typedef, which is binding, with
+// local non-binding wildcard variables.
+
+// SharedOptions=--enable-experiment=wildcard-variables
+
+import 'package:expect/expect.dart';
+
+typedef _ = Type;
+
+_ function<_ extends _>([_ _ = _]) => _;
+
+void main<_ extends _>() {
+  _ _ = _;
+  final _ _ = _;
+  const _ _ = _;
+  _ foo<_ extends _>([_ _ = int]) => _;
+  _ bar<_ extends _>([_ _ = _]) => int;
+  Expect.type<Type>(foo());
+  Expect.type<int>(bar());
+}
+
+class CConst {
+  static const _ = 42;
+  void member<_>() {
+    var _ = _;
+    final _ = _;
+    const _ = _;
+    int _() => 1;
+    int foo<_>([String _ = "$_"]) => _;
+    _ = foo();
+  }
+}

tests/language/wildcard_variables/non_binding/top_level_variable_test.dart

@@ -0,0 +1,34 @@
+// Copyright (c) 2024, 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.
+
+// Test the interactions between a wildcard top-level variable, which is
+// binding, with local non-binding wildcard variables.
+
+// SharedOptions=--enable-experiment=wildcard-variables
+
+import 'package:expect/expect.dart';
+
+var _ = 2;
+
+void main() {
+  Clas().member();
+
+  int _ = _;
+  int _ = 2;
+  _ = 3;
+  Expect.equals(3, _);
+}
+
+class Clas<_> {
+  void member<_>() {
+    int _ = _;
+    int _ = 2;
+    Expect.equals(2, _);
+    _ = 4;
+    Expect.equals(4, _);
+
+    int foo<_>([int _ = 5]) => _;
+    Expect.equals(4, foo());
+  }
+}