[JDK26] javac 26 updated how var declarations are stored. Fixed the problem and added a test to confirm.

src/core/lombok/javac/handlers/HandleVal.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2010-2021 The Project Lombok Authors.
+ * Copyright (C) 2010-2026 The Project Lombok Authors.
  * 
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -123,6 +123,7 @@ public class HandleVal extends JavacASTAdapter {
 		if (localNode.getSourceVersion() >= 10) {
 			local.vartype = null;
 			localNode.getAst().setChanged();
+			VarDeclDeclKind.setDeclKindToVar(local);
 			return;
 		}
 		
@@ -211,4 +212,17 @@ public class HandleVal extends JavacASTAdapter {
 			return null;
 		}
 	}
+	
+	private static class VarDeclDeclKind {
+		private static final Field declKind = Permit.permissiveGetField(JCVariableDecl.class, "declKind");
+		private static final Field typePos = Permit.permissiveGetField(JCVariableDecl.class, "typePos");
+		private static final Enum<?> DECL_KIND_VAR = Permit.enumValue(JCVariableDecl.class.getName() + "$DeclKind", "VAR");
+		
+		private static void setDeclKindToVar(JCVariableDecl decl) {
+			if (declKind != null) {
+				Permit.permissiveSet(declKind, decl, DECL_KIND_VAR);
+				Permit.permissiveSet(typePos, decl, decl.pos);
+			}
+		}
+	}
 }

src/delombok/lombok/delombok/PrettyPrinter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2016-2025 The Project Lombok Authors.
+ * Copyright (C) 2016-2026 The Project Lombok Authors.
  * 
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -714,7 +714,9 @@ public class PrettyPrinter extends JCTree.Visitor {
 			if (tree.vartype == null || tree.vartype.pos == -1 || endPos(tree.vartype) == -1) {
 				print("var");
 			} else {
-				print(tree.vartype);
+				Object kind = readObject(tree, "declKind", null);
+				if (kind instanceof Enum<?> && "VAR".equals(((Enum<?>) kind).name())) print("var");
+				else print(tree.vartype);
 			}
 		} finally {
 			innermostArrayBracketsAreVarargs = false;

src/utils/lombok/permit/Permit.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2018-2025 The Project Lombok Authors.
+ * Copyright (C) 2018-2026 The Project Lombok Authors.
  * 
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -36,6 +36,7 @@ import org.eclipse.jdt.internal.compiler.ast.TypeReference;
 
 import com.sun.tools.javac.main.JavaCompiler;
 import com.sun.tools.javac.tree.JCTree.JCExpression;
+import com.sun.tools.javac.tree.JCTree.JCVariableDecl;
 import com.sun.tools.javac.util.List;
 
 // sunapi suppresses javac's warning about using Unsafe; 'all' suppresses eclipse's warning about the unspecified 'sunapi' key. Leave them both.
@@ -334,6 +335,15 @@ public class Permit {
 		}
 	}
 	
+	public static boolean permissiveSet(Field f, Object receiver, Object newValue) {
+		try {
+			set(f, receiver, newValue);
+			return true;
+		} catch (Exception ignore) {
+			return false;
+		}
+	}
+	
 	public static void reportReflectionProblem(Throwable initError, String msg) {
 		if (!isDebugReflection()) return;
 		System.err.println("** LOMBOK REFLECTION issue: " + msg);
@@ -348,9 +358,16 @@ public class Permit {
 		return Permit.<RuntimeException>sneakyThrow0(t);
 	}
 	
-	@SuppressWarnings("unchecked")
 	private static <T extends Throwable> T sneakyThrow0(Throwable t) throws T {
 		throw (T)t;
 	}
 	
+	public static Enum<?> enumValue(String enumTypeName, String enumValueName) {
+		try {
+			Class c = Class.forName(enumTypeName);
+			return Enum.valueOf(c, enumValueName);
+		} catch (Exception e) {
+			return null;
+		}
+	}
 }

test/transform/resource/after-delombok/ValUndenotable.java

@@ -0,0 +1,10 @@
+// version 14:
+public class ValUndenotable {
+	public void method(int arg) {
+		final var x = new Object() {
+			void foo() {
+			}
+		};
+		x.foo();
+	}
+}

test/transform/resource/before/ValUndenotable.java

@@ -0,0 +1,12 @@
+// version 14:
+import lombok.val;
+
+public class ValUndenotable {
+	public void method(int arg) {
+		val x = new Object() {
+			void foo() {
+			}
+		};
+		x.foo();
+	}
+}