diff --git a/tower/src/util/mod.rs b/tower/src/util/mod.rs
index 3ca56ad26..7e34b65ce 100644
--- a/tower/src/util/mod.rs
+++ b/tower/src/util/mod.rs
@@ -112,7 +112,6 @@ pub trait ServiceExt<Request>: tower_service::Service<Request> {
     fn call_all<S>(self, reqs: S) -> CallAll<Self, S>
     where
         Self: Sized,
-        Self::Error: Into<crate::BoxError>,
         S: futures_core::Stream<Item = Request>,
     {
         CallAll::new(self, reqs)