a initialization of variable like "var o = null;" will throw the compile time error "variable initializer is 'null'"

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

@@ -23,6 +23,7 @@ package lombok.eclipse.handlers;
 
 import lombok.ConfigurationKeys;
 import lombok.core.HandlerPriority;
+import lombok.core.LombokNode;
 import lombok.eclipse.DeferUntilPostDiet;
 import lombok.eclipse.EclipseASTAdapter;
 import lombok.eclipse.EclipseASTVisitor;
@@ -33,11 +34,13 @@ import org.eclipse.jdt.internal.compiler.ast.ArrayInitializer;
 import org.eclipse.jdt.internal.compiler.ast.ForStatement;
 import org.eclipse.jdt.internal.compiler.ast.ForeachStatement;
 import org.eclipse.jdt.internal.compiler.ast.LocalDeclaration;
+import org.eclipse.jdt.internal.compiler.ast.NullLiteral;
 import org.eclipse.jdt.internal.compiler.ast.TypeReference;
 import org.mangosdk.spi.ProviderFor;
 
 import static lombok.core.handlers.HandlerUtil.handleFlagUsage;
 import static lombok.eclipse.handlers.EclipseHandlerUtil.typeMatches;
+import static lombok.javac.handlers.HandleVal.VARIABLE_INITIALIZER_IS_NULL;
 
 /*
  * This class just handles 3 basic error cases. The real meat of eclipse 'val' support is in {@code PatchVal} and {@code PatchValEclipse}.
@@ -81,5 +84,11 @@ public class HandleVal extends EclipseASTAdapter {
 		if (local.initialization != null && local.initialization.getClass().getName().equals("org.eclipse.jdt.internal.compiler.ast.LambdaExpression")) {
 			localNode.addError("'" + annotation + "' is not allowed with lambda expressions.");
 		}
+		
+		if(isVar && local.initialization instanceof NullLiteral) addVarNullInitMessage(localNode);
+	}
+	
+	public static void addVarNullInitMessage(LombokNode localNode) {
+		localNode.addError(VARIABLE_INITIALIZER_IS_NULL);
 	}
 }

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

@@ -22,7 +22,10 @@
 package lombok.javac.handlers;
 
 import static lombok.core.handlers.HandlerUtil.*;
+import static lombok.eclipse.handlers.HandleVal.addVarNullInitMessage;
 import static lombok.javac.handlers.JavacHandlerUtil.*;
+
+import com.sun.tools.javac.tree.JCTree.JCLiteral;
 import lombok.ConfigurationKeys;
 import lombok.experimental.var;
 import lombok.val;
@@ -51,7 +54,9 @@ import com.sun.tools.javac.util.List;
 @HandlerPriority(65536) // 2^16; resolution needs to work, so if the RHS expression is i.e. a call to a generated getter, we have to run after that getter has been generated.
 @ResolutionResetNeeded
 public class HandleVal extends JavacASTAdapter {
-
+	
+	public static final String VARIABLE_INITIALIZER_IS_NULL = "variable initializer is 'null'";
+	
 	private static boolean eq(String typeTreeToString, String key) {
 		return (typeTreeToString.equals(key) || typeTreeToString.equals("lombok." + key));
 	}
@@ -118,6 +123,9 @@ public class HandleVal extends JavacASTAdapter {
 		try {
 			if (rhsOfEnhancedForLoop == null) {
 				if (local.init.type == null) {
+					if (isVar && local.init instanceof JCLiteral && ((JCLiteral) local.init).value == null) {
+						addVarNullInitMessage(localNode);
+					}
 					JavacResolution resolver = new JavacResolution(localNode.getContext());
 					try {
 						type = ((JCExpression) resolver.resolveMethodMember(localNode).get(local.init)).type;

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

@@ -1,4 +1,5 @@
-class VarNullInit {
+
+public class VarNullInit {
 	void method() {
 		java.lang.Object x = null;
 	}

test/transform/resource/after-ecj/VarNullInit.java

@@ -1,7 +1,6 @@
 import lombok.experimental.var;
-
-class VarNullInit {
-  VarNullInit() {
+public class VarNullInit {
+  public VarNullInit() {
     super();
   }
   void method() {

test/transform/resource/before/VarNullInit.java

@@ -1,7 +1,7 @@
 //CONF: lombok.var.flagUsage = ALLOW
 import lombok.experimental.var;
 
-class VarNullInit {
+public class VarNullInit {
 	void method() {
 		var x = null;
 	}

test/transform/resource/messages-delombok/VarNullInit.java.messages

@@ -0,0 +1 @@
+6 variable initializer is 'null'

test/transform/resource/messages-ecj/VarNullInit.java.messages

@@ -0,0 +1 @@
+6 variable initializer is 'null'