Case C-802/18: Judgment of the Court (Sixth Chamber) of 2 April 2020 (request for a preliminary ruling from the Conseil supérieur de la Sécurité sociale — Luxembourg) — Caisse pour l'avenir des enfants v FV, GW (Reference for a preliminary ruling — Article 45 TFEU — Social security for migrant workers — Regulation (EC) No 883/2004 — Article 1(i) — Freedom of movement for workers — Equal treatment — Social advantages — Directive 2004/38/EC — Article 2(2) — Regulation (EU) No 492/2011 — Article 7(2) — Family allowance — Concept of ‘family members’ — Exclusion of children of spouses of non-resident workers — Difference in treatment vis-à-vis children of spouses of resident workers — Justification)