1 files changed, 13 insertions, 2 deletions
diff --git a/mingling_core/src/program/hook.rs b/mingling_core/src/program/hook.rs
index db1691b..7d94a21 100644
--- a/mingling_core/src/program/hook.rs
+++ b/mingling_core/src/program/hook.rs
@@ -144,8 +144,9 @@ where
 {
     /// Adds a typed hook to the program. The hook will be called at the appropriate
     /// lifecycle events.
-    pub fn with_hook(&mut self, hook: ProgramHook<C>) {
+    pub fn with_hook(&mut self, hook: ProgramHook<C>) -> &mut Self {
         self.hooks.push(hook);
+        self
     }
 
     pub(crate) fn run_hook_on_begin(&self, info: HookBeginInfo) {
@@ -694,7 +695,17 @@ mod tests {
         }
     }
 
-    impl Grouped<MockHookEnum> for MockHookEnum {
+    /// SAFETY:
+    ///
+    /// This implementation is only for testing purposes to satisfy trait bounds.
+    /// Since this code only constructs `AnyOutput` and calls methods like
+    /// `downcast`, `is`, `restore`, `route_chain`, and `route_renderer` —
+    /// none of which involve `ProgramCollect::do_chain` or
+    /// `ProgramCollect::render` — the type/member_id correspondence is
+    /// never exploited in an unsafe way here.
+    /// The caller must ensure that the associated `member_id` correctly
+    /// corresponds to the type's role in the group.
+    unsafe impl Grouped<MockHookEnum> for MockHookEnum {
         fn member_id() -> MockHookEnum {
             MockHookEnum::A
         }