From 689f637c7eba3c2449baccb1937aa36543b44b53 Mon Sep 17 00:00:00 2001
From: "Demi M. Obenour" <demiobenour@gmail.com>
Date: Fri, 7 Aug 2020 21:44:51 -0400
Subject: [PATCH] Implement the `concat` in `twox_64_concat`

---
 src/metadata.rs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/metadata.rs b/src/metadata.rs
index bbaf478d8a..3ef160cfc9 100644
--- a/src/metadata.rs
+++ b/src/metadata.rs
@@ -274,7 +274,13 @@ impl StorageMetadata {
             StorageHasher::Blake2_256 => sp_core::blake2_256(bytes).to_vec(),
             StorageHasher::Twox128 => sp_core::twox_128(bytes).to_vec(),
             StorageHasher::Twox256 => sp_core::twox_256(bytes).to_vec(),
-            StorageHasher::Twox64Concat => sp_core::twox_64(bytes).to_vec(),
+            StorageHasher::Twox64Concat => {
+                sp_core::twox_64(bytes)
+                    .iter()
+                    .chain(bytes)
+                    .cloned()
+                    .collect()
+            }
         }
     }