diff --git a/engine/src/engine/engine_event_handling.rs b/engine/src/engine/engine_event_handling.rs
index a074505..29b659e 100644
--- a/engine/src/engine/engine_event_handling.rs
+++ b/engine/src/engine/engine_event_handling.rs
@@ -33,7 +33,7 @@ pub struct InputMap {
     pub direction_mapping: HashMap<Keycode, GuiDirection>,
 }
 
-pub trait EventSystem<Func, T> {
+pub trait EventSystem<Func, C> {
     fn event_system(world_builder: &mut WorldBuilder, func: Func);
 }
 
@@ -405,6 +405,7 @@ macro_rules! impl_event_system {
 }
 
 impl_event_system!();
+impl_event_system!(A,);
 impl_event_system!(A, B,);
 impl_event_system!(A, B, C,);
 impl_event_system!(A, B, C, D,);