Type Alias F<T>

F:
    | Leaf
    | t_eq<T>
    | t_ref<T>
    | t_array<T>
    | t_record<T>
    | t_optional<T>
    | t_union<T[]>
    | t_intersect<readonly T[]>
    | t_tuple<T[]>
    | t_object<{ [x: string]: T }>