default:
		panic(fmt.Sprintf("unknown type %T", typ))
	}
}

func (w *Walker) writeSignature(buf *bytes.Buffer, sig *types.Signature) {
	if tparams := sig.TypeParams(); tparams != nil {
		w.writeTypeParams(buf, tparams, true)
	}
	w.writeParams(buf, sig.Params(), sig.Variadic())
	switch res := sig.Results(); res.Len() {
	case 0:
		// nothing to do
	case 1:
		buf.WriteByte(' ')