def List.concat

Base · base.bend:939

939def List.concat(a, -A: Kind(a), xss: List<a, List<a, A>>) -> List<a, A>:
940  match xss:
941    case Nil{}:
942      Nil{}
943    case h <> t:
944      List.append(a, A, h, List.concat(a, A, t))