From 30f59670c8c2843fe6852b37e0637b0d52eb9ada Mon Sep 17 00:00:00 2001
From: gralpli <25158727+gralpli@users.noreply.github.com>
Date: Wed, 2 Jan 2019 21:29:30 +0100
Subject: [PATCH] Clarify what `NoopWaker` does (#819)

---
 tokio-async-await/src/compat/backward.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tokio-async-await/src/compat/backward.rs b/tokio-async-await/src/compat/backward.rs
index 53a3fdf5a5b..8c5999b139d 100644
--- a/tokio-async-await/src/compat/backward.rs
+++ b/tokio-async-await/src/compat/backward.rs
@@ -84,6 +84,6 @@ unsafe impl UnsafeWake for NoopWaker {
     }
 
     unsafe fn wake(&self) {
-        panic!("NoopWake cannot wake");
+        unimplemented!("async-await-preview currently only supports futures 0.1. Use the compatibility layer of futures 0.3 instead, if you want to use futures 0.3.");
     }
 }