List.combine stack overflow

List.combine stack overflow

[Roland Zumkeller]

Hi,

List.combine fails in this example:

# let rec ulist = function 0 -> [] | n -> () :: ulist (n-1);;
...
# let x = ulist 30000;;
...
# List.combine x x;;
Stack overflow during evaluation (looping recursion?).

However, with a *copy* of 'combine' from stdlib/list.ml it suddenly works:

# let rec combine l1 l2 =
  match (l1, l2) with
    ([], []) -> []
  | (a1::l1, a2::l2) -> (a1, a2) :: combine l1 l2
  | (_, _) -> invalid_arg "List.combine";;
...
# combine x x;;
[((), ()); ((), ()); ((), ()); ((), ()); ((), ()); ((), ()); ...]

Why does 'combine' in the standard library behave differently from its
own copy? Is it compiled with different options?

Best,

Roland