4 files changed, 138 insertions, 1 deletions

diff --git a/src/delombok/lombok/delombok/PrettyPrinter.java b/src/delombok/lombok/delombok/PrettyPrinter.java
index e2742a27..fc5eaec2 100644
--- a/src/delombok/lombok/delombok/PrettyPrinter.java
+++ b/src/delombok/lombok/delombok/PrettyPrinter.java
@@ -1312,6 +1312,11 @@ public class PrettyPrinter extends JCTree.Visitor {
 				print(";");
 				needsNewLine = true;
 				needsAlign = true;
+			} else if (tree.stats.head.getClass().getSimpleName().equals("JCYield")) {
+				print((JCExpression) readObject(tree.stats.head, "value", null));
+				print(";");
+				needsNewLine = true;
+				needsAlign = true;
 			} else {
 				print(tree.stats.head);
 				if (tree.stats.head instanceof JCBlock) needsNewLine = false;
@@ -1341,7 +1346,10 @@ public class PrettyPrinter extends JCTree.Visitor {
 			print(")");
 		}
 		println(" {");
+		boolean ruleStyle = isCaseRuleStyle(tree.cases.head);
+		if (ruleStyle) indent++;
 		print(tree.cases, "");
+		if (ruleStyle) indent--;
 		aPrintln("}", tree);
 	}
 	
@@ -1357,10 +1365,20 @@ public class PrettyPrinter extends JCTree.Visitor {
 		}
 		println(" {");
 		List<JCCase> cases = readObject(tree, "cases", null);
+		boolean ruleStyle = isCaseRuleStyle(cases.head);
+		if (ruleStyle) indent++;
 		print(cases, "");
+		if (ruleStyle) indent--;
 		aPrint("}");
 	}
 	
+	void printYieldExpression(JCTree tree) {
+		aPrint("yield ");
+		JCExpression value = readObject(tree, "value", null);
+		print(value);
+		println(";", tree);
+	}
+	
 	@Override public void visitTry(JCTry tree) {
 		aPrint("try ");
 		List<?> resources = readObject(tree, "resources", List.nil());
@@ -1581,11 +1599,19 @@ public class PrettyPrinter extends JCTree.Visitor {
 			// Starting with JDK9, this is inside the import list, but we've already printed it. Just ignore it.
 		} else if ("JCSwitchExpression".equals(simpleName)) { // Introduced as preview feature in JDK12
 			printSwitchExpression(tree);
+		} else if ("JCYield".equals(simpleName)) { // Introduced as preview feature in JDK13, part of switch expressions.
+			printYieldExpression(tree);
 		} else {
 			throw new AssertionError("Unhandled tree type: " + tree.getClass() + ": " + tree);
 		}
 	}
 	
+	private boolean isCaseRuleStyle(JCCase tree) {
+		if (tree == null) return false;
+		Enum<?> caseKind = readObject(tree, "caseKind", null); // JDK 12+
+		return caseKind != null && caseKind.name().equalsIgnoreCase("RULE");
+	}
+	
 	private boolean jcAnnotatedTypeInit = false;
 	private Class<?> jcAnnotatedTypeClass = null;
 	
diff --git a/test/pretty/resource/after/Switch13.java b/test/pretty/resource/after/Switch13.java
new file mode 100644
index 00000000..363b48dc
--- /dev/null
+++ b/test/pretty/resource/after/Switch13.java
@@ -0,0 +1,55 @@
+public class Switch13 {
+	public void basic() {
+		switch (5) {
+		case 1: 
+		case 2: 
+			System.out.println("OK");
+			break;
+		default: 
+		}
+	}
+
+	public void multiCase() {
+		switch (5) {
+		case 1, 2: 
+			System.out.println("OK");
+		default: 
+		}
+	}
+
+	public int switchExpr1() {
+		return switch (5) {
+			case 1, 2 -> 0;
+			case 3 -> {
+				yield 10;
+			}
+			default -> 10;
+		} + 10;
+	}
+
+	public int switchExpr2() {
+		return switch (5) {
+		case 1, 2: 
+			System.out.println("Hello");
+		case 3: 
+			yield 10;
+		default: 
+			yield 20;
+		} + 10;
+	}
+
+	public void arrowSwitch() {
+		switch (5) {
+			case 1, 2 -> System.out.println("Hello");
+			case 3 -> {
+				System.out.println("");
+				break;
+			}
+		}
+	}
+
+	public void emptySwitch() {
+		switch (5) {
+		}
+	}
+}
\ No newline at end of file
diff --git a/test/pretty/resource/before/Switch12.java b/test/pretty/resource/before/Switch12.java
index f1bd8a79..d708f93c 100644
--- a/test/pretty/resource/before/Switch12.java
+++ b/test/pretty/resource/before/Switch12.java
@@ -1,4 +1,4 @@
-// version 12:
+// version 12:12
 public class Switch12 {
 	public void basic() {
 		switch (5) {
diff --git a/test/pretty/resource/before/Switch13.java b/test/pretty/resource/before/Switch13.java
new file mode 100644
index 00000000..fe590788
--- /dev/null
+++ b/test/pretty/resource/before/Switch13.java
@@ -0,0 +1,56 @@
+// version 13:
+public class Switch13 {
+	public void basic() {
+		switch (5) {
+		case 1:
+		case 2:
+			System.out.println("OK");
+			break;
+		default:
+		}
+	}
+
+	public void multiCase() {
+		switch (5) {
+		case 1, 2:
+			System.out.println("OK");
+		default:
+		}
+	}
+
+	public int switchExpr1() {
+		return switch (5) {
+			case 1, 2 -> 0;
+			case 3 -> {
+				yield 10;
+			}
+			default -> 10;
+		} + 10;
+	}
+	
+	public int switchExpr2() {
+		return switch (5) {
+		case 1, 2:
+			System.out.println("Hello");
+		case 3:
+			yield 10;
+		default:
+			yield 20;
+		} + 10;
+	}
+	
+	public void arrowSwitch() {
+		switch (5) {
+			case 1, 2 -> System.out.println("Hello");
+			case 3 -> {
+				System.out.println("");
+				break;
+			}
+		}
+	}
+	
+	public void emptySwitch() {
+		switch (5) {
+		}
+	}
+}