[tests] Enum shorthands - Expressions with no context (simple identifiers).

Testing expressions where enum shorthands might pop up and making sure there are no crashes.

Follow up to Erik's comment: https://dart-review.googlesource.com/c/sdk/+/393606/comments/16e214b1_4bbfad8f

Bug: #57038
Change-Id: Ia72b7f40f47dfc782085f56473ee68c5bd755d2b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/397500
Commit-Queue: Kallen Tu <[email protected]>
Reviewed-by: Erik Ernst <[email protected]>

Author: kallentu

tests/language/enum_shorthands/no_context/simple_identifier_no_context_error_test.dart

@@ -0,0 +1,149 @@
+// 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 that there are no crashes when enum shorthands are used in places
+// with no context type, or it's not allowed.
+
+// SharedOptions=--enable-experiment=enum-shorthands
+
+import '../enum_shorthand_helper.dart';
+
+void main() async {
+  // Enum shorthands in postfix and prefix expressions.
+  .red++;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  .red--;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  ++.red;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  --.red;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  -.red;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  ~.red;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  !.red;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  // Await.
+  await .red;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  // Parenthesis.
+  (.red);
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  // Map operators.
+  var map = <Color, Color> {.red: .red, .blue: .blue, .green: .green};
+  map[.red];
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  map[.blue] = Color.red;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  // Null assert.
+  .one!;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  // Assignment operators.
+  .red = 1;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  .red *= 1;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  .red /= 1;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  .red ~/= 1;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  .red %= 1;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  .red += 1;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  .red -= 1;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  .red <<= 1;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  .red >>>= 1;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  .red >>= 1;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  .red &= 1;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  .red ^= 1;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  .red |= 1;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+
+  .red ??= 1;
+  // ^
+  // [analyzer] unspecified
+  // [cfe] unspecified
+}