[issue #2730] Javadoc generated by lombok in javac now gets its position set.

This may fix 'IllegalArgumentException' errors when using google errorprone.

src/delombok/lombok/delombok/DocCommentIntegrator.java

@@ -89,7 +89,7 @@ public class DocCommentIntegrator {
 			((Map<JCTree, String>) map_).put(node, docCommentContent);
 			return true;
 		} else if (Javac.instanceOfDocCommentTable(map_)) {
-			CommentAttacher_8.attach(node, docCommentContent, map_);
+			CommentAttacher_8.attach(node, docCommentContent, cmt.pos, map_);
 			return true;
 		}
 		
@@ -98,7 +98,7 @@ public class DocCommentIntegrator {
 	
 	/* Container for code which will cause class loader exceptions on javac below 8. By being in a separate class, we avoid the problem. */
 	private static class CommentAttacher_8 {
-		static void attach(final JCTree node, String docCommentContent, Object map_) {
+		static void attach(final JCTree node, String docCommentContent, final int pos, Object map_) {
 			final String docCommentContent_ = docCommentContent;
 			((DocCommentTable) map_).putComment(node, new Comment() {
 				@Override public String getText() {
@@ -106,7 +106,7 @@ public class DocCommentIntegrator {
 				}
 				
 				@Override public int getSourcePos(int index) {
-					return -1;
+					return pos + index;
 				}
 				
 				@Override public CommentStyle getStyle() {

src/utils/lombok/javac/Javac.java

@@ -279,6 +279,17 @@ public class Javac {
 		return null;
 	}
 	
+	/**
+	 * Checks if the javadoc comment associated with {@code tree} has a position set.
+	 * 
+	 * Returns true if there is no javadoc comment on the node, or it has position (position isn't -1).
+	 */
+	public static boolean validateDocComment(JCCompilationUnit cu, JCTree tree) {
+		Object dc = getDocComments(cu);
+		if (!instanceOfDocCommentTable(dc)) return true;
+		return JavadocOps_8.validateJavadoc(dc, tree);
+	}
+	
 	@SuppressWarnings("unchecked")
 	public static void setDocComment(JCCompilationUnit cu, JCTree node, String javadoc) {
 		if (javadoc == null) return;
@@ -302,6 +313,12 @@ public class Javac {
 			return javadoc.getText();
 		}
 		
+		public static boolean validateJavadoc(Object dc, JCTree node) {
+			DocCommentTable dct = (DocCommentTable) dc;
+			Comment javadoc = dct.getComment(node);
+			return javadoc == null || javadoc.getText() == null || javadoc.getSourcePos(0) >= 0;
+		}
+		
 		static void setJavadoc(Object dc, JCTree node, String javadoc) {
 			DocCommentTable dct = (DocCommentTable) dc;
 			Comment newCmt = createJavadocComment(javadoc, node);
@@ -315,7 +332,7 @@ public class Javac {
 				}
 				
 				@Override public int getSourcePos(int index) {
-					return -1;
+					return field == null ? -1 : field.getStartPosition();
 				}
 				
 				@Override public CommentStyle getStyle() {

test/core/src/lombok/RunTestsViaDelombok.java

@@ -99,6 +99,10 @@ public class RunTestsViaDelombok extends AbstractRunTests {
 					try {
 						if (tree instanceof JCModifiers) return;
 						
+						if (!Javac.validateDocComment(unit, tree)) {
+							fail("Start position of doc comment (" + Javac.getDocComment(unit, tree) + ") of " + tree + " not set");
+						}
+						
 						if (tree.pos == -1) {
 							fail("Start position of " + tree + " not set");
 						}