I'm really not sure what you mean by "modularity". There's a lot of languages with much more readable and composable type declarations than C. For example in OCaml:

  let x : (int list ref, string) result option =
    let x1 : int = 0 in
    let x2 : int list = [ x1 ] in
    let x3 : int list ref = ref x2 in
    let x4 : (int list ref, string) result = Ok x3 in
    Some x4

The declaration of List.map:

  val map : ('a -> 'b) -> 'a list -> 'b list