#2420. Add another variable pattern exhaustiveness test (#2469)

Add another variable pattern exhaustiveness test

Author: sgrekhov

LanguageFeatures/Extension-types/exhaustiveness_variable_A03_t01.dart

@@ -0,0 +1,86 @@
+// 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.
+
+/// @assertion Exhaustiveness of a variable pattern is determined by the static
+/// type of the corresponding variable.
+///
+/// @description Check that the lifted space union of a variable pattern is
+/// determined by the static type of the corresponding variable.
+/// @author [email protected]
+
+// SharedOptions=--enable-experiment=inline-class
+
+import "../../Utils/expect.dart";
+
+extension type BoolET1(bool _) {}
+extension type BoolET2(bool _) implements bool {}
+
+String test1_1(BoolET1 o) {
+  switch (o) {
+    case bool _b:
+      return "exhaustive";
+  }
+}
+
+String test1_2(BoolET2 o) {
+  switch (o) {
+    case bool _b:
+      return "exhaustive";
+  }
+}
+
+String test1_3(BoolET1 o) {
+  switch (o) {
+    case BoolET1 _b:
+      return "exhaustive";
+  }
+}
+
+String test1_4(BoolET2 o) {
+  switch (o) {
+    case BoolET2 _b:
+      return "exhaustive";
+  }
+}
+
+String test1_5(BoolET1 o) {
+  switch (o) {
+    case BoolET2 _b:
+      return "exhaustive";
+  }
+}
+
+String test1_6(BoolET2 o) {
+  switch (o) {
+    case BoolET1 _b:
+      return "exhaustive";
+  }
+}
+
+String test2_1(BoolET1 o) => switch (o) {
+      var v => "exhaustive"
+    };
+
+String test2_2(BoolET2 o) => switch (o) {
+      var v => "exhaustive"
+    };
+
+main() {
+  Expect.equals("exhaustive", test1_1(BoolET1(true)));
+  Expect.equals("exhaustive", test1_1(BoolET1(false)));
+  Expect.equals("exhaustive", test1_2(BoolET2(true)));
+  Expect.equals("exhaustive", test1_2(BoolET2(false)));
+  Expect.equals("exhaustive", test1_3(BoolET1(true)));
+  Expect.equals("exhaustive", test1_3(BoolET1(false)));
+  Expect.equals("exhaustive", test1_4(BoolET2(true)));
+  Expect.equals("exhaustive", test1_4(BoolET2(false)));
+  Expect.equals("exhaustive", test1_5(BoolET1(true)));
+  Expect.equals("exhaustive", test1_5(BoolET1(false)));
+  Expect.equals("exhaustive", test1_6(BoolET2(true)));
+  Expect.equals("exhaustive", test1_6(BoolET2(false)));
+  Expect.equals("exhaustive", test2_1(BoolET1(true)));
+  Expect.equals("exhaustive", test2_1(BoolET1(false)));
+  Expect.equals("exhaustive", test2_2(BoolET2(true)));
+  Expect.equals("exhaustive", test2_2(BoolET2(false)));
+}