diff --git a/eth2/fork_choice/src/optimised_lmd_ghost.rs b/eth2/fork_choice/src/optimised_lmd_ghost.rs
index 7104834cb..40dc029be 100644
--- a/eth2/fork_choice/src/optimised_lmd_ghost.rs
+++ b/eth2/fork_choice/src/optimised_lmd_ghost.rs
@@ -30,10 +30,8 @@ use fast_math::log2_raw;
 use std::collections::HashMap;
 use std::sync::Arc;
 use types::{
-    readers::BeaconBlockReader,
-    slot_epoch_height::{Height, Slot},
-    validator_registry::get_active_validator_indices,
-    BeaconBlock, Hash256,
+    readers::BeaconBlockReader, slot_epoch::Slot, slot_height::SlotHeight,
+    validator_registry::get_active_validator_indices, BeaconBlock, Hash256,
 };
 
 //TODO: Pruning - Children
@@ -77,7 +75,7 @@ pub struct OptimisedLMDGhost<T: ClientDB + Sized> {
     block_store: Arc<BeaconBlockStore<T>>,
     /// State storage access.
     state_store: Arc<BeaconStateStore<T>>,
-    max_known_height: Height,
+    max_known_height: SlotHeight,
 }
 
 impl<T> OptimisedLMDGhost<T>
@@ -93,7 +91,7 @@ where
             ancestors: vec![HashMap::new(); 16],
             latest_attestation_targets: HashMap::new(),
             children: HashMap::new(),
-            max_known_height: Height::new(0),
+            max_known_height: SlotHeight::new(0),
             block_store,
             state_store,
         }
@@ -118,7 +116,7 @@ where
             .ok_or_else(|| ForkChoiceError::MissingBeaconState(*state_root))?;
 
         let active_validator_indices = get_active_validator_indices(
-            &current_state.validator_registry,
+            &current_state.validator_registry[..],
             block_slot.epoch(EPOCH_LENGTH),
         );
 
@@ -137,7 +135,7 @@ where
     }
 
     /// Gets the ancestor at a given height `at_height` of a block specified by `block_hash`.
-    fn get_ancestor(&mut self, block_hash: Hash256, at_height: Height) -> Option<Hash256> {
+    fn get_ancestor(&mut self, block_hash: Hash256, at_height: SlotHeight) -> Option<Hash256> {
         // return None if we can't get the block from the db.
         let block_height = {
             let block_slot = self
@@ -186,7 +184,7 @@ where
     fn get_clear_winner(
         &mut self,
         latest_votes: &HashMap<Hash256, u64>,
-        block_height: Height,
+        block_height: SlotHeight,
     ) -> Option<Hash256> {
         // map of vote counts for every hash at this height
         let mut current_votes: HashMap<Hash256, u64> = HashMap::new();
diff --git a/eth2/fork_choice/src/slow_lmd_ghost.rs b/eth2/fork_choice/src/slow_lmd_ghost.rs
index e0e347cef..609d28ab2 100644
--- a/eth2/fork_choice/src/slow_lmd_ghost.rs
+++ b/eth2/fork_choice/src/slow_lmd_ghost.rs
@@ -28,9 +28,7 @@ use db::{
 use std::collections::HashMap;
 use std::sync::Arc;
 use types::{
-    readers::{BeaconBlockReader, BeaconStateReader},
-    slot_epoch_height::Slot,
-    validator_registry::get_active_validator_indices,
+    readers::BeaconBlockReader, slot_epoch::Slot, validator_registry::get_active_validator_indices,
     BeaconBlock, Hash256,
 };