private String processingErrorMessage(String target) {
    return String.format(
        "[%s:MiscError] %s was unable to process %s because not all of its dependencies could be "
            + "resolved. Check for compilation errors or a circular dependency with generated "
            + "code.",
        getClass().getSimpleName(), getClass().getCanonicalName(), target);
  }
Processes the valid elements, including those previously deferred by each step.
common/src/main/java/com/google/auto/common/BasicAnnotationProcessor.java