[jdk17] Add support for default cases

src/delombok/lombok/delombok/PrettyPrinter.java

@@ -1324,13 +1324,16 @@ public class PrettyPrinter extends JCTree.Visitor {
 	@Override public void visitCase(JCCase tree) {
 		// Starting with JDK12, switches allow multiple expressions per case, and can take the form of an expression (preview feature).
 		
-		List<JCExpression> pats = readObject(tree, "pats", null); // JDK 12+
+		List<JCTree> pats = readObject(tree, "labels", null); // JDK 17+
 		if (pats == null) {
-			JCExpression pat = readObject(tree, "pat", null); // JDK -11
-			pats = pat == null ? List.<JCExpression>nil() : List.of(pat);
+			pats = readObject(tree, "pats", null); // JDK 12-17
+		}
+		if (pats == null) {
+			JCTree pat = readObject(tree, "pat", null); // JDK -11
+			pats = pat == null ? List.<JCTree>nil() : List.of(pat);
 		}
 		
-		if (pats.isEmpty()) {
+		if (pats.isEmpty() || pats.get(0).getClass().getName().endsWith("$JCDefaultCaseLabel")) {
 			aPrint("default");
 		} else {
 			aPrint("case ");

src/utils/lombok/javac/JavacTreeMaker.java

@@ -607,7 +607,19 @@ public class JavacTreeMaker {
 	
 	public JCCase Case(JCExpression pat, List<JCStatement> stats) {
 		if (tryResolve(Case11)) return invoke(Case11, pat, stats);
-		return invoke(Case12.Case12, Case12.CASE_KIND_STATEMENT, pat == null ? com.sun.tools.javac.util.List.nil() : com.sun.tools.javac.util.List.of(pat), stats, null);
+		List<JCTree> labels;
+		if (pat == null) {
+			labels = tryResolve(DefaultCaseLabel) ? List.of(DefaultCaseLabel()) : List.<JCTree>nil();
+		} else {
+			labels = List.<JCTree>of(pat);
+		}
+		return invoke(Case12.Case12, Case12.CASE_KIND_STATEMENT, labels, stats, null);
+	}
+	
+	//javac versions: 17
+	private static final MethodId<JCTree> DefaultCaseLabel = MethodId("DefaultCaseLabel", JCTree.class);
+	public JCTree DefaultCaseLabel() {
+		return invoke(DefaultCaseLabel);
 	}
 	
 	//javac versions: 6-8