diff --git a/lib/credo/check/readability/large_numbers.ex b/lib/credo/check/readability/large_numbers.ex
index 6023ba815..f0aa4f40b 100644
--- a/lib/credo/check/readability/large_numbers.ex
+++ b/lib/credo/check/readability/large_numbers.ex
@@ -181,7 +181,7 @@ defmodule Credo.Check.Readability.LargeNumbers do
       Enum.map(allowed_trailing_digits, fn trailing_digits ->
         if String.length(string) > trailing_digits do
           base =
-            Credo.Backports.String.slice(string, 0..(-1 * trailing_digits - 1))
+            Credo.Backports.String.slice(string, Range.new(0, -1 * trailing_digits - 1, -1))
             |> String.reverse()
             |> String.replace(~r/(\d{3})(?=\d)/, "\\1_")
             |> String.reverse()
diff --git a/lib/credo/check/warning/unused_function_return_helper.ex b/lib/credo/check/warning/unused_function_return_helper.ex
index a61b12f36..46877d105 100644
--- a/lib/credo/check/warning/unused_function_return_helper.ex
+++ b/lib/credo/check/warning/unused_function_return_helper.ex
@@ -132,7 +132,7 @@ defmodule Credo.Check.Warning.UnusedFunctionReturnHelper do
          when is_list(arguments) do
       # IO.inspect(ast, label: "#{unquote(op)} (#{Macro.to_string(candidate)} #{acc})")
 
-      head_expression = Credo.Backports.Enum.slice(arguments, 0..-2//-1)
+      head_expression = Credo.Backports.Enum.slice(arguments, Range.new(0, -2, -1))
 
       if Credo.Code.contains_child?(head_expression, candidate) do
         {nil, :VERIFIED}