Hi,

In Odoo 17+ (and now 18), XML expressions in views use a limited domain-like syntax, and ref('base.do') is not valid within a field attribute, such as invisible or readonly.

Please refer to the code below:

Python

from odoo import models, fields, api

class ResPartner(models.Model):

    _inherit = 'res.partner'

    is_dominican = fields.Boolean(compute="_compute_is_dominican", store=False)

    @api.depends('country_id')

    def _compute_is_dominican(self):

        dom_country = self.env.ref('base.do', raise_if_not_found=False)

        for rec in self:

            rec.is_dominican = rec.country_id == dom_country

XML

<field name="vat" placeholder="e.g. 123456789" string="RNC"

       readonly="not parent_id"

       invisible="not is_dominican or not is_company"

       required="is_fiscal_info_required"/>

<field name="vat" placeholder="e.g. 00112345678" string="Cédula"

       readonly="not parent_id"

       invisible="not is_dominican or is_company"

       required="is_fiscal_info_required"/>

Hope it helps.

Your best bet is to define a computed boolean field on that model, i.e. show_child_contact_vat, and use it as the invisible condition.