func (w *Walker) sortedEmbeddeds(typ *types.Interface) []string {
	n := typ.NumEmbeddeds()
	list := make([]string, 0, n)
	for i := 0; i < n; i++ {
		emb := typ.EmbeddedType(i)
		switch emb := emb.(type) {
		case *types.Interface:
			list = append(list, w.sortedEmbeddeds(emb)...)
		case *types.Union:
			var buf bytes.Buffer
			nu := emb.Len()
			for i := 0; i < nu; i++ {