[#1808] Probable fix: Using module names with dots in them was causing issues, as we only use the simple name. Actually getting the full module name is a little tricky, but this should do the job.

doc/changelog.markdown

@@ -2,7 +2,8 @@ Lombok Changelog
 ----------------
 
 ### v1.18.3 "Edgy Guinea Pig"
-* FEATURE: THe `@FieldNameConstants` feature has been completely redesigned. [Issue #1774](https://github.com/rzwitserloot/lombok/issues/1774) [FieldNameConstants documentation](https://projectlombok.org/features/experimental/FieldNameConstants)
+* FEATURE: The `@FieldNameConstants` feature has been completely redesigned. [Issue #1774](https://github.com/rzwitserloot/lombok/issues/1774) [FieldNameConstants documentation](https://projectlombok.org/features/experimental/FieldNameConstants)
+* BUGFIX: When using lombok to compile modularized (`module-info.java`-style) code, if the module name has dots in it, it wouldn't work. [Issue #1808](https://github.com/rzwitserloot/lombok/issues/1808)
 
 ### v1.18.2 (July 26th, 2018)
 * BUGFIX: mapstruct + lombok in eclipse should hopefully work again. [Issue #1359](https://github.com/rzwitserloot/lombok/issues/1359) and [mapstruct issue #1159](https://github.com/mapstruct/mapstruct/issues/1159)

src/core/lombok/javac/apt/LombokProcessor.java

@@ -43,6 +43,7 @@ import javax.annotation.processing.RoundEnvironment;
 import javax.annotation.processing.SupportedAnnotationTypes;
 import javax.lang.model.SourceVersion;
 import javax.lang.model.element.Element;
+import javax.lang.model.element.QualifiedNameable;
 import javax.lang.model.element.TypeElement;
 import javax.tools.Diagnostic.Kind;
 import javax.tools.JavaFileManager;
@@ -380,10 +381,7 @@ public class LombokProcessor extends AbstractProcessor {
 	
 	private String getModuleNameFor(Element element) {
 		while (element != null) {
-			if (element.getKind().name().equals("MODULE")) {
-				String n = element.getSimpleName().toString().trim();
-				return n.isEmpty() ? null : n;
-			}
+			if (element.getKind().name().equals("MODULE")) return ModuleNameOracle.getModuleName(element);
 			Element n = element.getEnclosingElement();
 			if (n == element) return null;
 			element = n;
@@ -391,6 +389,15 @@ public class LombokProcessor extends AbstractProcessor {
 		return null;
 	}
 	
+	// QualifiedNameable is a java7 thing, so to remain compatible with java6, shove this into an inner class to avoid the ClassNotFoundError.
+	private static class ModuleNameOracle {
+		static String getModuleName(Element element) {
+			if (!(element instanceof QualifiedNameable)) return null;
+			String name = ((QualifiedNameable) element).getQualifiedName().toString().trim();
+			return name.isEmpty() ? null : name;
+		}
+	}
+	
 	private JCCompilationUnit toUnit(Element element) {
 		TreePath path = trees == null ? null : trees.getPath(element);
 		if (path == null) return null;