diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 5984ddc..07f09fe 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -13,7 +13,7 @@ jobs:
           - ubuntu-latest
         ocaml-compiler:
           - 4.07.x
-          - 5.0.x
+          - 5.3.x
         package:
           - mock
           - mock-ounit
diff --git a/src/mock.ml b/src/mock.ml
index 5a64a08..3c57e0b 100644
--- a/src/mock.ml
+++ b/src/mock.ml
@@ -40,11 +40,11 @@ let call mock args =
   | None
     ->
     Stdlib.raise (Mock_not_configured mock.name)
-  | Some effect
+  | Some side_effect
     ->
     begin
       mock.params := args :: !(mock.params);
-      eval_side_effect effect
+      eval_side_effect side_effect
     end
 
 let recorded_calls mock =