generator/src/org/immutables/generator/AnnotationMirrors.java
@SuppressWarnings("unchecked")
  public static List<? extends AnnotationMirror> from(TypeMirror type) {
    return (List<? extends AnnotationMirror>) GetTypeAnnotations.get(type);
  }
@SuppressWarnings("unchecked")
  public static List<? extends AnnotationMirror> from(TypeMirror type) {
    return (List<? extends AnnotationMirror>) GetTypeAnnotations.get(type);
  }
safe unchecked: known return type list or empty immutable list