make PeerNameSet a more broadly used type

router/connection_maker.go

@@ -114,7 +114,7 @@ func (cm *ConnectionMaker) checkStateAndAttemptConnections() time.Duration {
 	validTarget := make(map[string]struct{})
 
 	// copy the set of things we are connected to, so we can access them without locking
-	ourConnectedPeers := make(map[PeerName]struct{})
+	ourConnectedPeers := make(PeerNameSet)
 	ourConnectedTargets := make(map[string]struct{})
 	for _, conn := range cm.ourself.Connections() {
 		ourConnectedPeers[conn.Remote().Name] = struct{}{}

router/mocks_test.go

@@ -48,7 +48,7 @@ func newMockConnection(from, to *Peer) Connection {
 }
 
 func checkEqualConns(t *testing.T, ourName PeerName, got, wanted map[PeerName]Connection) {
-	checkConns := make(map[PeerName]struct{})
+	checkConns := make(PeerNameSet)
 	for _, conn := range wanted {
 		checkConns[conn.Remote().Name] = struct{}{}
 	}

router/peers.go

@@ -23,6 +23,8 @@ type NameCollisionError struct {
 	Name PeerName
 }
 
+type PeerNameSet map[PeerName]struct{}
+
 func NewPeers(ourself *Peer, onGC func(*Peer)) *Peers {
 	return &Peers{
 		ourself: ourself,

router/router.go

@@ -350,8 +350,6 @@ func handleSpecialFrame(relayConn *LocalConnection, sender *net.UDPAddr, frame [
 
 // Gossiper methods - the Router is the topology Gossiper
 
-type PeerNameSet map[PeerName]struct{}
-
 type TopologyGossipData struct {
 	peers  *Peers
 	update PeerNameSet