diff --git a/crates/bevy_ecs/macros/src/lib.rs b/crates/bevy_ecs/macros/src/lib.rs
index 5006196d0bb3d..3fe40c33ec9da 100644
--- a/crates/bevy_ecs/macros/src/lib.rs
+++ b/crates/bevy_ecs/macros/src/lib.rs
@@ -533,6 +533,7 @@ pub fn derive_system_param(input: TokenStream) -> TokenStream {
                 {}
             }
         }
+        // For unconditionally mutable params, we simply do not implement `ReadOnlySystemParam`.
         ParamAccess::Mutable => quote! {},
     };