diff --git a/src/header/map.rs b/src/header/map.rs
index 2344c659..ea276d11 100644
--- a/src/header/map.rs
+++ b/src/header/map.rs
@@ -3255,7 +3255,7 @@ mod as_header_name {
 
 #[test]
 fn test_bounds() {
-    fn check_bounds<T: Send + Send>() {}
+    fn check_bounds<T: Send + Sync>() {}
 
     check_bounds::<HeaderMap<()>>();
     check_bounds::<Iter<'static, ()>>();
diff --git a/src/header/name.rs b/src/header/name.rs
index cf4088c4..06c33009 100644
--- a/src/header/name.rs
+++ b/src/header/name.rs
@@ -2024,7 +2024,7 @@ mod tests {
 
     #[test]
     fn test_bounds() {
-        fn check_bounds<T: Sync + Send>() {}
+        fn check_bounds<T: Send + Sync>() {}
         check_bounds::<HeaderName>();
     }