diff --git a/eth2/state_processing/src/get_genesis_state.rs b/eth2/state_processing/src/get_genesis_state.rs
index d11154888..0fe78c1ed 100644
--- a/eth2/state_processing/src/get_genesis_state.rs
+++ b/eth2/state_processing/src/get_genesis_state.rs
@@ -23,7 +23,7 @@ pub fn get_genesis_beacon_state<T: EthSpec>(
     process_deposits(&mut state, genesis_validator_deposits, spec)?;
 
     // Process genesis activations.
-    for (i, validator) in state.validator_registry.iter_mut().enumerate() {
+    for validator in &mut state.validator_registry {
         if validator.effective_balance >= spec.max_effective_balance {
             validator.activation_eligibility_epoch = spec.genesis_epoch;
             validator.activation_epoch = spec.genesis_epoch;
diff --git a/eth2/state_processing/src/per_block_processing.rs b/eth2/state_processing/src/per_block_processing.rs
index fba96b833..e8b271f44 100644
--- a/eth2/state_processing/src/per_block_processing.rs
+++ b/eth2/state_processing/src/per_block_processing.rs
@@ -286,8 +286,8 @@ pub fn process_attester_slashings<T: EthSpec>(
         )
         .map_err(|e| e.into_with_index(i))?;
 
-        let slashable_indices = get_slashable_indices(&state, &attester_slashing, spec)
-            .map_err(|e| e.into_with_index(i))?;
+        let slashable_indices =
+            get_slashable_indices(&state, &attester_slashing).map_err(|e| e.into_with_index(i))?;
 
         for i in slashable_indices {
             slash_validator(state, i as usize, None, spec)?;
diff --git a/eth2/state_processing/src/per_block_processing/validate_attestation.rs b/eth2/state_processing/src/per_block_processing/validate_attestation.rs
index 44eb02616..1058c0d21 100644
--- a/eth2/state_processing/src/per_block_processing/validate_attestation.rs
+++ b/eth2/state_processing/src/per_block_processing/validate_attestation.rs
@@ -77,7 +77,7 @@ fn validate_attestation_parametric<T: EthSpec>(
 
     // Verify the Casper FFG vote.
     if !time_independent_only {
-        verify_casper_ffg_vote(attestation, state, spec)?;
+        verify_casper_ffg_vote(attestation, state)?;
     }
 
     // Crosslink data root is zero (to be removed in phase 1).
@@ -103,7 +103,6 @@ fn validate_attestation_parametric<T: EthSpec>(
 fn verify_casper_ffg_vote<T: EthSpec>(
     attestation: &Attestation,
     state: &BeaconState<T>,
-    spec: &ChainSpec,
 ) -> Result<(), Error> {
     let data = &attestation.data;
     if data.target_epoch == state.current_epoch() {
diff --git a/eth2/state_processing/src/per_block_processing/verify_attester_slashing.rs b/eth2/state_processing/src/per_block_processing/verify_attester_slashing.rs
index 7b227900a..7e1fa5e66 100644
--- a/eth2/state_processing/src/per_block_processing/verify_attester_slashing.rs
+++ b/eth2/state_processing/src/per_block_processing/verify_attester_slashing.rs
@@ -35,7 +35,7 @@ pub fn verify_attester_slashing<T: EthSpec>(
     Ok(())
 }
 
-/// For a given attester slashing, return the indices able to be slashed.
+/// For a given attester slashing, return the indices able to be slashed in ascending order.
 ///
 /// Returns Ok(indices) if `indices.len() > 0`.
 ///
@@ -43,14 +43,10 @@ pub fn verify_attester_slashing<T: EthSpec>(
 pub fn get_slashable_indices<T: EthSpec>(
     state: &BeaconState<T>,
     attester_slashing: &AttesterSlashing,
-    spec: &ChainSpec,
 ) -> Result<Vec<u64>, Error> {
-    get_slashable_indices_modular(
-        state,
-        attester_slashing,
-        |_, validator| validator.is_slashable_at(state.current_epoch()),
-        spec,
-    )
+    get_slashable_indices_modular(state, attester_slashing, |_, validator| {
+        validator.is_slashable_at(state.current_epoch())
+    })
 }
 
 /// Same as `gather_attester_slashing_indices` but allows the caller to specify the criteria
@@ -59,7 +55,6 @@ pub fn get_slashable_indices_modular<F, T: EthSpec>(
     state: &BeaconState<T>,
     attester_slashing: &AttesterSlashing,
     is_slashable: F,
-    spec: &ChainSpec,
 ) -> Result<Vec<u64>, Error>
 where
     F: Fn(u64, &Validator) -> bool,