diff --git a/rustler_mix/lib/rustler/compiler/config.ex b/rustler_mix/lib/rustler/compiler/config.ex
index badaac41..dc508fe0 100644
--- a/rustler_mix/lib/rustler/compiler/config.ex
+++ b/rustler_mix/lib/rustler/compiler/config.ex
@@ -38,12 +38,12 @@ defmodule Rustler.Compiler.Config do
     # TODO: Remove in 1.0
     rustler_crates =
       if mix_config = Mix.Project.config()[:rustler_crates] do
-        mix_config
-      else
         IO.warn(
           ":rustler_crates in mix.exs is deprecated, please explicitly pass options on `use Rustler` or configure the module in your `config/*.exs` files"
         )
 
+        mix_config
+      else
         []
       end