[21][pattern switch] ParameterizedType in Exhaustive check not done.

[mpalat]

Reproduced from https://bugs.eclipse.org/bugs/show_bug.cgi?id=579360

from Alexander Kriegisch - reproduced verbatim:
From bug 576746 comment 5

public class SwitchPatternPreview2OK {
sealed interface I permits A, B {}
final static class A implements I {}
final static class B implements I {}

static int testGenericSealedExhaustive(I i) {
return switch (i) {
// Exhaustive as no A case possible!
case B bi -> 42;
};
}
}

---

$ java -jar org.eclipse.jdt.core/target/org.eclipse.jdt.core-3.29.50-SNAPSHOT-batch-compiler.jar -18 --enable-preview ../AspectJ/tests/features199/java18/SwitchPatternPreview2OK.java
Picked up _JAVA_OPTIONS: -Djava.net.preferIPv4Stack=true

1. WARNING in C:\Users\alexa\Documents\java-src\AspectJ\tests\features199\java18\SwitchPatternPreview2OK.java (at line 2)
   sealed interface I permits A, B {}
   ^
   SwitchPatternPreview2OK.A is a raw type. References to generic type SwitchPatternPreview2OK.A should be parameterized

---

2. WARNING in C:\Users\alexa\Documents\java-src\AspectJ\tests\features199\java18\SwitchPatternPreview2OK.java (at line 2)
   sealed interface I permits A, B {}
   ^
   SwitchPatternPreview2OK.B is a raw type. References to generic type SwitchPatternPreview2OK.B should be parameterized

---

3. ERROR in C:\Users\alexa\Documents\java-src\AspectJ\tests\features199\java18\SwitchPatternPreview2OK.java (at line 7)
   return switch (i) {
   ^
   A switch expression should have a default case

---

4. WARNING in C:\Users\alexa\Documents\java-src\AspectJ\tests\features199\java18\SwitchPatternPreview2OK.java (at line 8)
   // Exhaustive as no A case possible!
   case B bi -> 42;
   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   You are using a preview language feature that may or may not be supported in a future release

---

4 problems (1 error, 3 warnings)

---

So it seems as if the improved exhaustiveness logic has not been implemented yet either.

[kriegaex]

@mpalat, @jarthana: I just re-tested this on JDK 20 and the current batch compiler after the Java 20 merge to the main branch. This issue is still unresolved. Javcac 20 compiles it fine, ECJ does not.

Again, the code I just compiled with both compilers:

/**
 * Inspired by examples in https://openjdk.org/jeps/427
 */
public class SwitchPatternPreview4OK {
  /**
   * According to an example from JEP 420, this should work with preview 2 (Java 18), and it does with Javac,
   * but not with ECJ for Java 18, 19 and 20.
   *
   * See:
   *   https://openjdk.java.net/jeps/420#2--Exhaustiveness-of-switch-expressions-and-statements
   *   https://bugs.eclipse.org/bugs/show_bug.cgi?id=579360
   *   https://github.com/eclipse-jdt/eclipse.jdt.core/issues/587
   *
   * TODO: reactivate when implemented or move to preview 5 with Java 21.
   */
  sealed interface I<T> permits D, E {}
  final static class D<X> implements I<String> {}
  final static class E<Y> implements I<Y> {}

  static int testGenericSealedExhaustive(I<Integer> i) {
    return switch (i) {
      // Exhaustive as no D case possible!
      case E<Integer> bi -> 42;
    };
  }
}

[mpalat]

done