It should be noted, however, that in some cases the legislation prohibits the establishment of systems of regulation through collective autonomy, different from those provided for by law, and, in other cases, prohibits the provision of more favourable conditions for workers (e.g.B. immediately after the revolution, but still in the 1989 Dismissal Act). Portuguese labour law contains various such restrictions. In 1975 and 1976, a number of issues were totally or partially excluded from the competence of the social partners (who succeeded in the law), such as the termination of the employment contract, fixed-term contracts and the regulation of annual leave, public holidays and absences from work. Despite these restrictions, collective agreements often contain provisions such as clauses contrary to the law, which often set more favourable conditions for workers with regard to disciplinary proceedings, leave and absences. Similarly, until recently, the prohibition on the provision of supplementary social security benefits, imposed by Article 6(1) of the Law on collective work, was systematically ignored. The courts have begun to question the validity of such provisions. .