From a3b9c2af7d7d7c5eda566c7110637b3f4a6b23b3 Mon Sep 17 00:00:00 2001
From: Robert Habermeier <rphmeier@gmail.com>
Date: Wed, 31 Jan 2018 22:28:11 +0100
Subject: [PATCH] fix compiler warning

---
 substrate/state-machine/src/lib.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/substrate/state-machine/src/lib.rs b/substrate/state-machine/src/lib.rs
index e497a20474..f0c1d17b8b 100644
--- a/substrate/state-machine/src/lib.rs
+++ b/substrate/state-machine/src/lib.rs
@@ -19,7 +19,8 @@
 #![warn(missing_docs)]
 
 extern crate polkadot_primitives as primitives;
-#[macro_use]
+
+#[cfg_attr(test, macro_use)]
 extern crate hex_literal;
 
 extern crate hashdb;