code: public void organizeTypeAnnotationsSignatures(final Env<AttrContext> env, final JCClassDecl tree) {
          annotate.afterTypes(() -> {
              JavaFileObject oldSource = log.useSource(env.toplevel.sourcefile);
              try {
                  new TypeAnnotationPositions(true).scan(tree);
              } finally {
                  log.useSource(oldSource);
              }
          });
      }
docs: Separate type annotations from declaration annotations and
  determine the correct positions for type annotations.
  This version only visits types in signatures and should be
  called from MemberEnter.