diff --git a/Sources/BeaconChain/BeaconChain.swift b/Sources/BeaconChain/BeaconChain.swift
index 305452a..5e1d294 100644
--- a/Sources/BeaconChain/BeaconChain.swift
+++ b/Sources/BeaconChain/BeaconChain.swift
@@ -442,7 +442,7 @@ extension BeaconChain {
 
 extension BeaconChain {
 
-    static func slashValidator(state: inout BeaconState, index: ValidatorIndex) {
+    static func slash(_ state: inout BeaconState, validator index: ValidatorIndex) {
         assert(state.slot < state.validatorRegistry[Int(index)].withdrawableEpoch.startSlot())
         state.validatorRegistry[Int(index)].exit(state: state)
 
diff --git a/Sources/BeaconChain/StateTransition.swift b/Sources/BeaconChain/StateTransition.swift
index 16587eb..dd952df 100644
--- a/Sources/BeaconChain/StateTransition.swift
+++ b/Sources/BeaconChain/StateTransition.swift
@@ -104,7 +104,7 @@ extension StateTransition {
                 )
             )
 
-            BeaconChain.slashValidator(state: &state, index: proposerSlashing.proposerIndex)
+            BeaconChain.slash(&state, validator: proposerSlashing.proposerIndex)
         }
     }
 
@@ -132,7 +132,7 @@ extension StateTransition {
             assert(slashableIndices.count >= 1)
 
             for i in slashableIndices {
-                BeaconChain.slashValidator(state: &state, index: i)
+                BeaconChain.slash(&state, validator: i)
             }
         }
     }