diff --git a/eth2/state_processing/src/per_block_processing/verify_deposit.rs b/eth2/state_processing/src/per_block_processing/verify_deposit.rs
index 2aeab6c5a..80d8bc24f 100644
--- a/eth2/state_processing/src/per_block_processing/verify_deposit.rs
+++ b/eth2/state_processing/src/per_block_processing/verify_deposit.rs
@@ -3,11 +3,8 @@ use hashing::hash;
 use merkle_proof::verify_merkle_proof;
 use ssz::ssz_encode;
 use ssz_derive::Encode;
-use std::collections::HashMap;
 use types::*;
 
-pub type PublicKeyValidatorIndexHashmap = HashMap<PublicKey, u64>;
-
 /// Indicates if a `Deposit` is valid to be included in a block in the current epoch of the given
 /// state.
 ///
diff --git a/eth2/state_processing/src/per_epoch_processing/process_validator_registry.rs b/eth2/state_processing/src/per_epoch_processing/process_validator_registry.rs
index c830bfc24..26ebd60b3 100644
--- a/eth2/state_processing/src/per_epoch_processing/process_validator_registry.rs
+++ b/eth2/state_processing/src/per_epoch_processing/process_validator_registry.rs
@@ -14,7 +14,7 @@ pub fn process_validator_registry(state: &mut BeaconState, spec: &ChainSpec) ->
     state.previous_shuffling_seed = state.current_shuffling_seed;
 
     if should_update_validator_registry(state, spec)? {
-        state.update_validator_registry(spec);
+        state.update_validator_registry(spec)?;
 
         state.current_shuffling_epoch = next_epoch;
         state.current_shuffling_start_shard = (state.current_shuffling_start_shard
@@ -37,7 +37,7 @@ pub fn process_validator_registry(state: &mut BeaconState, spec: &ChainSpec) ->
         }
     }
 
-    state.process_slashings(spec);
+    state.process_slashings(spec)?;
     state.process_exit_queue(spec);
 
     Ok(())
diff --git a/eth2/types/src/beacon_state/epoch_cache.rs b/eth2/types/src/beacon_state/epoch_cache.rs
index 75d791e8f..ca8bcc70e 100644
--- a/eth2/types/src/beacon_state/epoch_cache.rs
+++ b/eth2/types/src/beacon_state/epoch_cache.rs
@@ -7,7 +7,6 @@ use swap_or_not_shuffle::shuffle_list;
 #[derive(Debug, PartialEq)]
 pub enum Error {
     UnableToShuffle,
-    NoValidators { epoch: Epoch },
     UnableToGenerateSeed,
 }
 
@@ -259,17 +258,19 @@ impl EpochCrosslinkCommitteesBuilder {
     }
 
     pub fn build(self, spec: &ChainSpec) -> Result<EpochCrosslinkCommittees, Error> {
-        if self.active_validator_indices.is_empty() {
-            return Err(Error::NoValidators { epoch: self.epoch });
-        }
-
-        let shuffled_active_validator_indices = shuffle_list(
-            self.active_validator_indices,
-            spec.shuffle_round_count,
-            &self.shuffling_seed[..],
-            true,
-        )
-        .ok_or_else(|| Error::UnableToShuffle)?;
+        // The shuffler fails on a empty list, so if there are no active validator indices, simply
+        // return an empty list.
+        let shuffled_active_validator_indices = if self.active_validator_indices.is_empty() {
+            vec![]
+        } else {
+            shuffle_list(
+                self.active_validator_indices,
+                spec.shuffle_round_count,
+                &self.shuffling_seed[..],
+                true,
+            )
+            .ok_or_else(|| Error::UnableToShuffle)?
+        };
 
         let mut committees: Vec<Vec<usize>> = shuffled_active_validator_indices
             .honey_badger_split(self.committees_per_epoch as usize)
diff --git a/eth2/types/src/test_utils/testing_beacon_state_builder.rs b/eth2/types/src/test_utils/testing_beacon_state_builder.rs
index 8180673d1..e76a01e49 100644
--- a/eth2/types/src/test_utils/testing_beacon_state_builder.rs
+++ b/eth2/types/src/test_utils/testing_beacon_state_builder.rs
@@ -134,7 +134,7 @@ impl TestingBeaconStateBuilder {
         state.validator_registry = validators;
         state.validator_balances = balances;
 
-        debug!("BeaconState built.");
+        debug!("BeaconState initialized.");
 
         Self { state, keypairs }
     }