pkg go/ast, type CompositeLit struct, Incomplete bool
pkg go/token, method (*File) AddLineColumnInfo(int, string, int, int)
pkg go/types, func NewInterfaceType([]*Func, []Type) *Interface
pkg go/types, method (*Interface) EmbeddedType(int) Type
pkg go/types, method (*Var) Embedded() bool
pkg net, method (*ListenConfig) Listen(context.Context, string, string) (Listener, error)

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++ {