diff --git a/beacon_chain/utils/ssz/src/impl_decode.rs b/beacon_chain/utils/ssz/src/impl_decode.rs
index b86af1365..a6b8843bd 100644
--- a/beacon_chain/utils/ssz/src/impl_decode.rs
+++ b/beacon_chain/utils/ssz/src/impl_decode.rs
@@ -8,20 +8,20 @@ use super::{
 macro_rules! impl_decodable_for_uint {
     ($type: ident, $bit_size: expr) => {
         impl Decodable for $type {
-            fn ssz_decode(bytes: &[u8], index: usize)
+            fn ssz_decode(bytes: &[u8], start_bytes: usize)
                 -> Result<(Self, usize), DecodeError>
             {
                 assert!((0 < $bit_size) &
                         ($bit_size <= 64) &
                         ($bit_size % 8 == 0));
                 let max_bytes = $bit_size / 8;
-                if bytes.len() >= (index + max_bytes) {
-                    let end_bytes = index + max_bytes;
+                if bytes.len() >= (start_bytes + max_bytes) {
+                    let end_bytes = start_bytes + max_bytes;
                     let mut result: $type = 0;
-                    for i in index..end_bytes {
-                        let offset = ((index + max_bytes) - i - 1) * 8;
-                        result |= ($type::from(bytes[i])) << offset;
-                    };
+                    for (index, byte) in bytes.iter().enumerate().take(end_bytes).skip(start_bytes) {
+                        let offset = (end_bytes - index - 1) * 8;
+                        result |= ($type::from(*byte)) << offset;
+                    }
                     Ok((result, end_bytes))
                 } else {
                     Err(DecodeError::TooShort)
diff --git a/beacon_chain/utils/ssz/src/impl_encode.rs b/beacon_chain/utils/ssz/src/impl_encode.rs
index 392f8667e..36776e071 100644
--- a/beacon_chain/utils/ssz/src/impl_encode.rs
+++ b/beacon_chain/utils/ssz/src/impl_encode.rs
@@ -35,7 +35,7 @@ macro_rules! impl_encodable_for_uint {
                 }
 
                 // Append bytes to the SszStream
-                s.append_encoded_raw(&mut buf.to_vec());
+                s.append_encoded_raw(&buf.to_vec());
             }
         }
     }