diff --git a/src/libstd/panic.rs b/src/libstd/panic.rs
index 56d638d9df3b4..aff11d036f8f9 100644
--- a/src/libstd/panic.rs
+++ b/src/libstd/panic.rs
@@ -29,7 +29,7 @@ pub use panicking::{take_hook, set_hook, PanicInfo, Location};
 #[rustc_deprecated(since = "1.9.0", reason = "renamed to set_hook")]
 #[unstable(feature = "panic_handler", reason = "awaiting feedback", issue = "30449")]
 pub fn set_handler<F>(handler: F) where F: Fn(&PanicInfo) + 'static + Sync + Send {
-    set_hook(handler)
+    set_hook(Box::new(handler))
 }
 
 ///
diff --git a/src/libstd/panicking.rs b/src/libstd/panicking.rs
index 556dddf9387e2..fd6a15b0f69a3 100644
--- a/src/libstd/panicking.rs
+++ b/src/libstd/panicking.rs
@@ -58,12 +58,11 @@ static FIRST_PANIC: AtomicBool = AtomicBool::new(true);
 ///
 /// Panics if called from a panicking thread.
 #[unstable(feature = "panic_handler", reason = "awaiting feedback", issue = "30449")]
-pub fn set_hook<F>(hook: F) where F: Fn(&PanicInfo) + 'static + Sync + Send {
+pub fn set_hook(hook: Box<Fn(&PanicInfo) + 'static + Sync + Send>) {
     if thread::panicking() {
         panic!("cannot modify the panic hook from a panicking thread");
     }
 
-    let hook = Box::new(hook);
     unsafe {
         let lock = HOOK_LOCK.write();
         let old_hook = HOOK;