func walkDir(path string) {
	filepath.WalkDir(path, visitFile)
}

func visitFile(path string, f fs.DirEntry, err error) error {
	if err == nil && isGoFile(f) {
		err = processFile(path, false)
	}
	if err != nil {
		report(err)
	}
	return nil
}

func isGoFile(f fs.DirEntry) bool {
	// ignore non-Go files
	name := f.Name()
	return !f.IsDir() && !strings.HasPrefix(name, ".") && strings.HasSuffix(name, ".go")