func (r *calleesTypesResult) toSerial(res *serial.Result, fset *token.FileSet) {
	j := &serial.Callees{
		Pos:  fset.Position(r.site.Pos()).String(),
		Desc: "static function call",
	}
	j.Callees = []*serial.CalleesItem{
		&serial.CalleesItem{
			Name: r.callee.FullName(),
			Pos:  fset.Position(r.callee.Pos()).String(),
		},
	}
	res.Callees = j
}
func (r *calleesSSAResult) toSerial(res *serial.Result, fset *token.FileSet) {
	j := &serial.Callees{
		Pos:  fset.Position(r.site.Pos()).String(),
		Desc: r.site.Common().Description(),
	}
	for _, callee := range r.funcs {
		j.Callees = append(j.Callees, &serial.CalleesItem{
			Name: callee.String(),
			Pos:  fset.Position(callee.Pos()).String(),
		})
	}
	res.Callees = j
}