Added code to NOT add @SuppressWarnings to things if a @SuppressWarnings is already there. Lombok itself can't ever do that anyway (we don't add @SW except to things we just generated fresh), but some lombok extension builders do, and this helps them.

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

@@ -1388,6 +1388,19 @@ public class EclipseHandlerUtil {
 	private static final char[] ALL = "all".toCharArray();
 	
 	public static Annotation[] createSuppressWarningsAll(ASTNode source, Annotation[] originalAnnotationArray) {
+		if (originalAnnotationArray != null) for (Annotation ann : originalAnnotationArray) {
+			char[] lastToken = null;
+			
+			if (ann.type instanceof QualifiedTypeReference) {
+				char[][] t = ((QualifiedTypeReference) ann.type).tokens;
+				lastToken = t[t.length - 1];
+			} else if (ann.type instanceof SingleTypeReference) {
+				lastToken = ((SingleTypeReference) ann.type).token;
+			}
+			
+			if (lastToken != null && new String(lastToken).equals("SuppressWarnings")) return originalAnnotationArray;
+		}
+		
 		int pS = source.sourceStart, pE = source.sourceEnd;
 		long p = (long)pS << 32 | pE;
 		long[] poss = new long[3];

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

@@ -918,6 +918,14 @@ public class JavacHandlerUtil {
 	
 	private static void addSuppressWarningsAll(JCModifiers mods, JavacNode node, int pos, JCTree source, Context context) {
 		if (!LombokOptionsFactory.getDelombokOptions(context).getFormatPreferences().generateSuppressWarnings()) return;
+		for (JCAnnotation ann : mods.annotations) {
+			JCTree annType = ann.getAnnotationType();
+			Name lastPart = null;
+			if (annType instanceof JCIdent) lastPart = ((JCIdent) annType).name;
+			else if (annType instanceof JCFieldAccess) lastPart = ((JCFieldAccess) annType).name;
+			
+			if (lastPart != null && lastPart.contentEquals("SuppressWarnings")) return;
+		}
 		JavacTreeMaker maker = node.getTreeMaker();
 		JCExpression suppressWarningsType = genJavaLangTypeRef(node, "SuppressWarnings");
 		JCLiteral allLiteral = maker.Literal("all");