DS processing crashes when Pattern matching is used in a switch statement

[FlorianKroiss]

1. Configure a Plugin Project with Java 21 and enable DS processing.
2. Create a service interface:

package foo;

public interface FooService {

	void doStuff(Integer input);
	
}

3. Implement interface and add Component annotation:

package foo;

import org.osgi.service.component.annotations.Component;

@Component
public class FooServiceImpl implements FooService {

	@Override
	public void doStuff(Integer input) {
		switch(input) {
		case Integer i -> {} // java.lang.UnsupportedOperationException: Operation only supported in JLS21 AST
		//default -> {} // works
		}
	}

}

An error message pops up when saving the file:

Errors occurred during the build.
Errors running builder 'Java Builder' on project 'Dummy'.
Operation only supported in JLS21 AST

From the Error Log:

java.lang.UnsupportedOperationException: Operation only supported in JLS21 AST
	at org.eclipse.jdt.core.dom.ASTNode.supportedOnlyIn21(ASTNode.java:2587)
	at org.eclipse.jdt.core.dom.Pattern.<init>(Pattern.java:42)
	at org.eclipse.jdt.core.dom.NullPattern.<init>(NullPattern.java:66)
	at org.eclipse.jdt.core.dom.ASTConverter.createFakeNullPattern(ASTConverter.java:4883)
	at org.eclipse.jdt.core.dom.ASTConverter.convert(ASTConverter.java:2941)
	at org.eclipse.jdt.core.dom.ASTConverter.convert(ASTConverter.java:2039)
	at org.eclipse.jdt.core.dom.ASTConverter.convert(ASTConverter.java:1486)
	at org.eclipse.jdt.core.dom.ASTConverter.convert(ASTConverter.java:3197)
	at org.eclipse.jdt.core.dom.ASTConverter.convert(ASTConverter.java:3334)
	at org.eclipse.jdt.core.dom.ASTConverter.convert(ASTConverter.java:3221)
	at org.eclipse.jdt.core.dom.ASTConverter.convert(ASTConverter.java:813)
	at org.eclipse.jdt.core.dom.ASTConverter.buildBodyDeclarations(ASTConverter.java:208)
	at org.eclipse.jdt.core.dom.ASTConverter.convert(ASTConverter.java:3567)
	at org.eclipse.jdt.core.dom.ASTConverter.convert(ASTConverter.java:1595)
	at org.eclipse.jdt.core.dom.CompilationUnitResolver.resolve(CompilationUnitResolver.java:1052)
	at org.eclipse.jdt.core.dom.CompilationUnitResolver.resolve(CompilationUnitResolver.java:739)
	at org.eclipse.jdt.core.dom.CompilationUnitResolver$ECJCompilationUnitResolver.resolve(CompilationUnitResolver.java:111)
	at org.eclipse.jdt.core.dom.ASTParser.createASTs(ASTParser.java:968)
	at org.eclipse.pde.ds.internal.annotations.DSAnnotationCompilationParticipant.processAnnotations(DSAnnotationCompilationParticipant.java:717)
	at org.eclipse.pde.ds.internal.annotations.DSAnnotationCompilationParticipant.processAnnotations(DSAnnotationCompilationParticipant.java:653)
	at org.eclipse.jdt.internal.core.builder.AbstractImageBuilder.processAnnotations(AbstractImageBuilder.java:770)
	at org.eclipse.jdt.internal.core.builder.AbstractImageBuilder.compile(AbstractImageBuilder.java:383)
	at org.eclipse.jdt.internal.core.builder.BatchImageBuilder.build(BatchImageBuilder.java:79)
	at org.eclipse.jdt.internal.core.builder.JavaBuilder.buildAll(JavaBuilder.java:286)
	at org.eclipse.jdt.internal.core.builder.JavaBuilder.build(JavaBuilder.java:198)
	at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:1077)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:47)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:296)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:352)
	at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:441)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:47)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:444)
	at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:555)
	at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:503)
	at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:585)
	at org.eclipse.core.internal.events.AutoBuildJob.doBuild(AutoBuildJob.java:207)
	at org.eclipse.core.internal.events.AutoBuildJob.run(AutoBuildJob.java:300)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63)

I did not dig into the problem to much, but I suppose the hard-coded JLS4 Constant is a part of the problem:

eclipse.pde/ds/org.eclipse.pde.ds.annotations/src/org/eclipse/pde/ds/internal/annotations/DSAnnotationCompilationParticipant.java

Line 705 in 2d6fc0c

ASTParser parser = ASTParser.newParser(AST.JLS4);