diff --git a/src/main.rs b/src/main.rs
index 1a414d5..5de2bd1 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -31,7 +31,6 @@ pub struct Map<F>(F);
 
 pub trait FnOnce1<A> {
     type Output;
-    fn call_once(self, arg: A) -> Self::Output;
 }
 
 impl<T, A, R> FnOnce1<A> for T
@@ -39,9 +38,6 @@ where
     T: FnOnce(A) -> R,
 {
     type Output = R;
-    fn call_once(self, arg: A) -> R {
-        loop {}
-    }
 }
 
 impl<F> Stream for Map<F>