Fixes #2010. Fix exhaustiveness tests for a cast-pattern (#2018)

LanguageFeatures/Patterns/Exhaustiveness/lifting_cast_pattern_A01_t01.dart

@@ -12,15 +12,14 @@
 ///     space union of E.
 ///
 /// @description Check a lifted space of a cast pattern in case of not sealed
-/// type
+/// type. Test switch statement
 /// @author [email protected]
 
 // SharedOptions=--enable-experiment=patterns
 
-int test1(Object obj) {
-//  ^^^^^
-// [analyzer] unspecified
-// [cfe] unspecified
+import "../../../Utils/expect.dart";
+
+int test(Object obj) {
   switch (obj) {
     case int(isEven: true) as int:
       return 1;
@@ -29,15 +28,7 @@ int test1(Object obj) {
   }
 }
 
-int test2(Object obj) => switch (obj) {
-//                       ^^^^^^
-// [analyzer] unspecified
-// [cfe] unspecified
-    int(isEven: true) as int => 1,
-    int _ => 2
-  };
-
 main() {
-  test1(1);
-  test2(2);
+  Expect.equals(2 ,test(1));
+  Expect.equals(1 ,test(2));
 }

LanguageFeatures/Patterns/Exhaustiveness/lifting_cast_pattern_A01_t02.dart

@@ -9,50 +9,23 @@
 /// - The lifted space union of the cast's subpattern in context C.
 /// - For each space E in the expanded spaces of M:
 ///   a. If E is not a subset of C and C is not a subset of M, then the lifted
-///   space union of E.
+///     space union of E.
 ///
-/// @description Check a lifted space of a cast pattern in case of a sealed type
+/// @description Check a lifted space of a cast pattern in case of not sealed
+/// type. Test switch element
 /// @author [email protected]
-/// @issue 51877
+/// @issue 51986
 
-// SharedOptions=--enable-experiment=patterns,class-modifiers
+// SharedOptions=--enable-experiment=patterns
 
 import "../../../Utils/expect.dart";
 
-sealed class A {
-  final int field;
-  A(this.field);
-}
-class B extends A {
-  B(int field) : super(field);
-}
-class C extends A {
-  C(int field) : super(field);
-}
-
-test1(A a) {
-  switch (a) {
-    case C(field: 0) as C:
-      return 0;
-    case C _:
-      return 1;
-  }
-}
-
-test2(A a) => switch (a) {
-  C(field: 0) as C => 0,
-  C _ => 1
-};
+int test(Object obj) => switch (obj) {
+    int(isEven: true) as int => 1,
+    int _ => 2
+  };
 
 main() {
-  Expect.equals(0, test1(C(0)));
-  Expect.equals(1, test1(C(1)));
-  Expect.throws(() {
-    test1(B(0));
-  });
-  Expect.equals(0, test2(C(0)));
-  Expect.equals(1, test2(C(1)));
-  Expect.throws(() {
-    test2(B(0));
-  });
+  Expect.equals(2 ,test(1));
+  Expect.equals(1 ,test(2));
 }

LanguageFeatures/Patterns/Exhaustiveness/lifting_cast_pattern_A02_t01.dart

@@ -0,0 +1,58 @@
+// 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 The lifted space union for a pattern with matched value type M is
+/// ...
+/// Cast pattern:
+/// The space union spaces for a cast pattern with cast type C is a union of:
+/// - The lifted space union of the cast's subpattern in context C.
+/// - For each space E in the expanded spaces of M:
+///   a. If E is not a subset of C and C is not a subset of M, then the lifted
+///   space union of E.
+///
+/// @description Check a lifted space of a cast pattern in case of a sealed type
+/// @author [email protected]
+/// @issue 51877
+
+// SharedOptions=--enable-experiment=patterns,class-modifiers
+
+import "../../../Utils/expect.dart";
+
+sealed class A {
+  final int field;
+  A(this.field);
+}
+class B extends A {
+  B(int field) : super(field);
+}
+class C extends A {
+  C(int field) : super(field);
+}
+
+test1(A a) {
+  switch (a) {
+    case C(field: 0) as C:
+      return 0;
+    case C _:
+      return 1;
+  }
+}
+
+test2(A a) => switch (a) {
+  C(field: 0) as C => 0,
+  C _ => 1
+};
+
+main() {
+  Expect.equals(0, test1(C(0)));
+  Expect.equals(1, test1(C(1)));
+  Expect.throws(() {
+    test1(B(0));
+  });
+  Expect.equals(0, test2(C(0)));
+  Expect.equals(1, test2(C(1)));
+  Expect.throws(() {
+    test2(B(0));
+  });
+}