diff --git a/src/github.com/matrix-org/dendrite/roomserver/input/events.go b/src/github.com/matrix-org/dendrite/roomserver/input/events.go
index dd0216f33..9c660a54e 100644
--- a/src/github.com/matrix-org/dendrite/roomserver/input/events.go
+++ b/src/github.com/matrix-org/dendrite/roomserver/input/events.go
@@ -120,7 +120,7 @@ func (ae *authEvents) ThirdPartyInvite(stateKey string) (*gomatrixserverlib.Even
 }
 
 func (ae *authEvents) lookupEventWithEmptyStateKey(typeNID int64) *gomatrixserverlib.Event {
-	eventNID, ok := ae.state.lookup(types.StateKey{typeNID, types.EmptyStateKeyNID})
+	eventNID, ok := ae.state.lookup(types.StateKeyTuple{typeNID, types.EmptyStateKeyNID})
 	if !ok {
 		return nil
 	}
@@ -136,7 +136,7 @@ func (ae *authEvents) lookupEvent(typeNID int64, stateKey string) *gomatrixserve
 	if !ok {
 		return nil
 	}
-	eventNID, ok := ae.state.lookup(types.StateKey{typeNID, stateKeyNID})
+	eventNID, ok := ae.state.lookup(types.StateKeyTuple{typeNID, stateKeyNID})
 	if !ok {
 		return nil
 	}
@@ -182,27 +182,27 @@ func loadAuthEvents(
 }
 
 // stateKeysNeeded works out which numeric state keys we need to authenticate some events.
-func stateKeysNeeded(stateNIDMap idMap, stateNeeded gomatrixserverlib.StateNeeded) []types.StateKey {
-	var keys []types.StateKey
+func stateKeysNeeded(stateNIDMap idMap, stateNeeded gomatrixserverlib.StateNeeded) []types.StateKeyTuple {
+	var keys []types.StateKeyTuple
 	if stateNeeded.Create {
-		keys = append(keys, types.StateKey{types.MRoomCreateNID, types.EmptyStateKeyNID})
+		keys = append(keys, types.StateKeyTuple{types.MRoomCreateNID, types.EmptyStateKeyNID})
 	}
 	if stateNeeded.PowerLevels {
-		keys = append(keys, types.StateKey{types.MRoomPowerLevelsNID, types.EmptyStateKeyNID})
+		keys = append(keys, types.StateKeyTuple{types.MRoomPowerLevelsNID, types.EmptyStateKeyNID})
 	}
 	if stateNeeded.JoinRules {
-		keys = append(keys, types.StateKey{types.MRoomJoinRulesNID, types.EmptyStateKeyNID})
+		keys = append(keys, types.StateKeyTuple{types.MRoomJoinRulesNID, types.EmptyStateKeyNID})
 	}
 	for _, member := range stateNeeded.Member {
 		stateKeyNID, ok := stateNIDMap.lookup(member)
 		if ok {
-			keys = append(keys, types.StateKey{types.MRoomMemberNID, stateKeyNID})
+			keys = append(keys, types.StateKeyTuple{types.MRoomMemberNID, stateKeyNID})
 		}
 	}
 	for _, token := range stateNeeded.ThirdPartyInvite {
 		stateKeyNID, ok := stateNIDMap.lookup(token)
 		if ok {
-			keys = append(keys, types.StateKey{types.MRoomThirdPartyInviteNID, stateKeyNID})
+			keys = append(keys, types.StateKeyTuple{types.MRoomThirdPartyInviteNID, stateKeyNID})
 		}
 	}
 	return keys
@@ -238,16 +238,16 @@ func newStateEntryMap(stateEntries []types.StateEntry) stateEntryMap {
 }
 
 // lookup an entry in the event map.
-func (m stateEntryMap) lookup(stateKey types.StateKey) (eventNID int64, ok bool) {
+func (m stateEntryMap) lookup(stateKey types.StateKeyTuple) (eventNID int64, ok bool) {
 	// Since the list is sorted we can implement this using binary search.
 	// This is faster than using a hash map.
 	// We don't have to worry about pathological cases because the keys are fixed
 	// size and are controlled by us.
 	list := []types.StateEntry(m)
 	i := sort.Search(len(list), func(i int) bool {
-		return !list[i].StateKey.LessThan(stateKey)
+		return !list[i].StateKeyTuple.LessThan(stateKey)
 	})
-	if i < len(list) && list[i].StateKey == stateKey {
+	if i < len(list) && list[i].StateKeyTuple == stateKey {
 		ok = true
 		eventNID = list[i].EventNID
 	}
diff --git a/src/github.com/matrix-org/dendrite/roomserver/types/types.go b/src/github.com/matrix-org/dendrite/roomserver/types/types.go
index bbab5a723..6cfbcfccf 100644
--- a/src/github.com/matrix-org/dendrite/roomserver/types/types.go
+++ b/src/github.com/matrix-org/dendrite/roomserver/types/types.go
@@ -13,17 +13,17 @@ type PartitionOffset struct {
 	Offset int64
 }
 
-// A StateKey is a pair of a numeric event type and a numeric state key.
+// A StateKeyTuple is a pair of a numeric event type and a numeric state key.
 // It is used to lookup state entries.
-type StateKey struct {
+type StateKeyTuple struct {
 	// The numeric ID for the event type.
 	EventTypeNID int64
-	// The numeric ID for the state key or 0 if the event is not a state event.
+	// The numeric ID for the state key.
 	EventStateKeyNID int64
 }
 
 // LessThan returns true if this state key is less than the other state key.
-func (a StateKey) LessThan(b StateKey) bool {
+func (a StateKeyTuple) LessThan(b StateKeyTuple) bool {
 	if a.EventTypeNID != b.EventTypeNID {
 		return a.EventTypeNID < b.EventTypeNID
 	}
@@ -32,15 +32,15 @@ func (a StateKey) LessThan(b StateKey) bool {
 
 // A StateEntry is an entry in the room state of a matrix room.
 type StateEntry struct {
-	StateKey
+	StateKeyTuple
 	// The numeric ID for the event.
 	EventNID int64
 }
 
 // LessThan returns true if this state entry is less than the other state entry.
 func (a StateEntry) LessThan(b StateEntry) bool {
-	if a.StateKey != b.StateKey {
-		return a.StateKey.LessThan(b.StateKey)
+	if a.StateKeyTuple != b.StateKeyTuple {
+		return a.StateKeyTuple.LessThan(b.StateKeyTuple)
 	}
 	return a.EventNID < b.EventNID
 }