From 61406b34bc8a7fc259f6b360452a82efe34c760e Mon Sep 17 00:00:00 2001
From: Paul Hauner <paul@paulhauner.com>
Date: Thu, 11 Jul 2019 12:45:34 +1000
Subject: [PATCH] Resolve issues raised from @michaelsproul review

---
 eth2/utils/ssz_types/src/bitfield.rs     | 8 +-------
 eth2/utils/ssz_types/src/fixed_vector.rs | 4 ++--
 2 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/eth2/utils/ssz_types/src/bitfield.rs b/eth2/utils/ssz_types/src/bitfield.rs
index 23231e09d..6af82b48d 100644
--- a/eth2/utils/ssz_types/src/bitfield.rs
+++ b/eth2/utils/ssz_types/src/bitfield.rs
@@ -347,7 +347,7 @@ impl<T: BitfieldBehaviour> Bitfield<T> {
 
     /// Returns true if no bits are set.
     pub fn is_zero(&self) -> bool {
-        !self.bytes.iter().any(|byte| (*byte & u8::max_value()) > 0)
+        self.bytes.iter().all(|byte| *byte == 0)
     }
 
     /// Compute the intersection (binary-and) of this bitfield with another.
@@ -517,9 +517,6 @@ impl<'de, N: Unsigned + Clone> Deserialize<'de> for Bitfield<Variable<N>> {
     where
         D: Deserializer<'de>,
     {
-        // We reverse the bit-order so that the BitVec library can read its 0th
-        // bit from the end of the hex string, e.g.
-        // "0xef01" => [0xef, 0x01] => [0b1000_0000, 0b1111_1110]
         let bytes = deserializer.deserialize_str(PrefixedHexVisitor)?;
         Self::from_ssz_bytes(&bytes)
             .map_err(|e| serde::de::Error::custom(format!("Bitfield {:?}", e)))
@@ -542,9 +539,6 @@ impl<'de, N: Unsigned + Clone> Deserialize<'de> for Bitfield<Fixed<N>> {
     where
         D: Deserializer<'de>,
     {
-        // We reverse the bit-order so that the BitVec library can read its 0th
-        // bit from the end of the hex string, e.g.
-        // "0xef01" => [0xef, 0x01] => [0b1000_0000, 0b1111_1110]
         let bytes = deserializer.deserialize_str(PrefixedHexVisitor)?;
         Self::from_ssz_bytes(&bytes)
             .map_err(|e| serde::de::Error::custom(format!("Bitfield {:?}", e)))
diff --git a/eth2/utils/ssz_types/src/fixed_vector.rs b/eth2/utils/ssz_types/src/fixed_vector.rs
index b5d422760..8d7c2264e 100644
--- a/eth2/utils/ssz_types/src/fixed_vector.rs
+++ b/eth2/utils/ssz_types/src/fixed_vector.rs
@@ -50,8 +50,8 @@ pub struct FixedVector<T, N> {
 }
 
 impl<T, N: Unsigned> FixedVector<T, N> {
-    /// Returns `Some` if the given `vec` equals the fixed length of `Self`. Otherwise returns
-    /// `None`.
+    /// Returns `Ok` if the given `vec` equals the fixed length of `Self`. Otherwise returns
+    /// `Err`.
     pub fn new(vec: Vec<T>) -> Result<Self, Error> {
         if vec.len() == Self::capacity() {
             Ok(Self {