**Impacted versions:**
11.0 
**Steps to reproduce:**
  - Create payslip
  - Add a contract with any structure
  - Add a structure in payslip, different from the one defined in step 2
  - Confirm or compute sheet

**Current behavior:**
Payslip is computed using the contract structure

**Expected behavior:**
Payslip should be computed using the payslip structure

**FYI:**  This is an issue because, sometimes, it's necessary to pay the employee using a structure different from their contract, e.g. in case of Christmas bonuses

**Video/Screenshot link (optional):**
[Video](https://www.youtube.com/watch?v=32H01n503uU&feature=youtu.be)


_name = 'hr.payslip.line'
    _inherit = 'hr.salary.rule'
    _description = 'Payslip Line'
    _order = 'contract_id, sequence'
    slip_id = fields.Many2one('hr.payslip', string='Pay Slip', required=True, ondelete='cascade')
    salary_rule_id = fields.Many2one('hr.salary.rule', string='Rule', required=True)
    employee_id = fields.Many2one('hr.employee', string='Employee', required=True)
    contract_id = fields.Many2one('hr.contract', string='Contract', required=True, index=True)
    rate = fields.Float(string='Rate (%)', digits=dp.get_precision('Payroll Rate'), default=100.0)
    amount = fields.Float(digits=dp.get_precision('Payroll'))
    quantity = fields.Float(digits=dp.get_precision('Payroll'), default=1.0)
    total = fields.Float(compute='_compute_total', string='Total', digits=dp.get_precision('Payroll'), store=True)
    @api.depends('quantity', 'amount', 'rate')
    def _compute_total(self):
        for line in self:
            line.total = float(line.quantity) * line.amount * line.rate / 100
    @api.model
    def create(self, values):
        if 'employee_id' not in values or 'contract_id' not in values:
            payslip = self.env['hr.payslip'].browse(values.get('slip_id'))
            values['employee_id'] = values.get('employee_id') or payslip.employee_id.id
            values['contract_id'] = values.get('contract_id') or payslip.contract_id and payslip.contract_id.id
            if not values['contract_id']:
                raise UserError(_('You must set a contract to create a payslip line.'))
        return super(HrPayslipLine, self).create(values)
class HrPayslipWorkedDays(models.Model):