[Sealed types][Enhanced Switch] Exhaustiveness in pattern matching switch is wrong

[jbyunes]

As designed in JEP 441: Pattern Matching for switch, Switches and enum constants the following code is correct as it is exhaustive:

sealed interface CardClassification permits Suit, Tarot {}
public enum Suit implements CardClassification { CLUBS, DIAMONDS, HEARTS, SPADES }
final class Tarot implements CardClassification {}
static void exhaustiveSwitchWithBetterEnumSupport(CardClassification c) {
    switch (c) {
        case Suit.CLUBS -> {
            System.out.println("It's clubs");
        }
        case Suit.DIAMONDS -> {
            System.out.println("It's diamonds");
        }
        case Suit.HEARTS -> {
            System.out.println("It's hearts");
        }
        case Suit.SPADES -> {
            System.out.println("It's spades");
        }
        case Tarot t -> {
            System.out.println("It's a tarot");
        }
    }
}

Eclipse Version: 2024-09 (4.33.0) Build id: 20240905-0614, compiler compliance 22 is activated, reports it as an error and necessitate a default case which is obviously wrong:

The code can be successfully compiled with any external Java compiler ≥21.

[srikanth-sankaran]

There have been numerous bug fixes in this area since 4.33. Are you able to test a recent I build to see if your problem is still there ??

[srikanth-sankaran]

This is most likely the same issue as #2720

[srikanth-sankaran]

This modified fuller program compiles and runs on master and prints:

sealed interface CardClassification permits Suit, Tarot {}
enum Suit implements CardClassification { CLUBS, DIAMONDS, HEARTS, SPADES }
final class Tarot implements CardClassification {}
public class X {
static void exhaustiveSwitchWithBetterEnumSupport(CardClassification c) {
    switch (c) {
        case Suit.CLUBS -> {
            System.out.println("It's clubs");
        }
        case Suit.DIAMONDS -> {
            System.out.println("It's diamonds");
        }
        case Suit.HEARTS -> {
            System.out.println("It's hearts");
        }
        case Suit.SPADES -> {
            System.out.println("It's spades");
        }
        case Tarot t -> {
            System.out.println("It's a tarot");
        }
    }
}
	public static void main(String[] args) {
		exhaustiveSwitchWithBetterEnumSupport(Suit.CLUBS);
		exhaustiveSwitchWithBetterEnumSupport(Suit.DIAMONDS);
		exhaustiveSwitchWithBetterEnumSupport(Suit.HEARTS);
		exhaustiveSwitchWithBetterEnumSupport(Suit.SPADES);
		exhaustiveSwitchWithBetterEnumSupport(new Tarot());
	}
}

compiles fine on master/HEAD and when run prints as expected:

It's clubs
It's diamonds
It's hearts
It's spades
It's a tarot

[srikanth-sankaran]

Yes, I am able to confirm that the problem shows up before commit 4494017 and goes away with it. Closing as a duplicate of #2720