diff --git a/lib/parse/datetime/helpers.ex b/lib/parse/datetime/helpers.ex
index 33fed705..eb78d1ff 100644
--- a/lib/parse/datetime/helpers.ex
+++ b/lib/parse/datetime/helpers.ex
@@ -159,13 +159,13 @@ defmodule Timex.Parse.DateTime.Helpers do
 
     case {padding, min_width, max_width} do
       {:zeroes, _, nil} -> Text.integer()
-      {:zeroes, min, max} -> choice(Enum.map(max..min//-1, &fixed_integer(&1)))
+      {:zeroes, min, max} -> choice(Enum.map(Range.new(max, min, -1), &fixed_integer(&1)))
       {:spaces, -1, nil} -> skip(spaces()) |> Text.integer()
       {:spaces, min, nil} -> skip(spaces()) |> fixed_integer(min)
-      {:spaces, _, max} -> skip(spaces()) |> choice(Enum.map(max..1//-1, &fixed_integer(&1)))
+      {:spaces, _, max} -> skip(spaces()) |> choice(Enum.map(Range.new(max, 1, -1), &fixed_integer(&1)))
       {_, -1, nil} -> Text.integer()
       {_, min, nil} -> fixed_integer(min)
-      {_, min, max} -> choice(Enum.map(max..min//-1, &fixed_integer(&1)))
+      {_, min, max} -> choice(Enum.map(Range.new(max, min, -1), &fixed_integer(&1)))
     end
   end
 end