guards in non pattern switches

[Remi Forax]

Only the pattern switch supports guards,
trying to use a guard inside a string switch, enum switch or int switch.

So with

  public static void example3() {
    enum Color { RED, BLACK }

    var color = Color.RED;
    var value = switch(color) {
      case RED && color != null -> 1;
      case RED -> 2;
      case BLACK -> 3;
    };
    System.out.println("value " + value);
  }
  
  public static void example4() {
    var aString = "bar";
    var anotherValue = 4;
    var value = switch(aString) {
      case "foo" && anotherValue == 4 -> 1;
      case "bar" -> 2;
      default -> 3;
    };
    System.out.println("value " + value);
  }

  public static void example5() {
    var aValue =10;
    var anotherValue = 4;
    var value = switch(aValue) {
      case 42 && anotherValue == 4 -> 1;
      case 10 -> 2;
      default -> 3;
    };
    System.out.println("value " + value);
  }


I get the following errors

PatternMatchingGuard.java:33: error: an enum switch case label must be the unqualified name of an enumeration constant
      case RED && color != null -> 1;
               ^
PatternMatchingGuard.java:44: error: bad operand types for binary operator '&&'
      case "foo" && anotherValue == 4 -> 1;
                 ^
  first type:  String
  second type: boolean
PatternMatchingGuard.java:55: error: bad operand types for binary operator '&&'
      case 42 && anotherValue == 4 -> 1;
              ^
  first type:  int
  second type: boolean
Note: PatternMatchingGuard.java uses preview features of Java SE 17.
Note: Recompile with -Xlint:preview for details.
3 errors

I believe that an error message saying that guards are not supported in enum switch, string switch and int switch is more user friendly.

regards,
Rémi