Improve dial error messages

swarm_dial.go

@@ -290,6 +290,9 @@ func (s *Swarm) dial(ctx context.Context, p peer.ID) (*Conn, error) {
 		that we previously had (halting a dial when we run out of addrs)
 	*/
 	goodAddrs := s.filterKnownUndialables(s.peers.Addrs(p))
+	if len(goodAddrs) == 0 {
+		return nil, errors.New("no good addresses")
+	}
 	goodAddrsChan := make(chan ma.Multiaddr, len(goodAddrs))
 	for _, a := range goodAddrs {
 		goodAddrsChan <- a
@@ -352,7 +355,7 @@ func (s *Swarm) dialAddrs(ctx context.Context, p peer.ID, remoteAddrs <-chan ma.
 	// use a single response type instead of errs and conns, reduces complexity *a ton*
 	respch := make(chan dialResult)
 
-	defaultDialFail := fmt.Errorf("failed to dial %s (default failure)", p)
+	defaultDialFail := inet.ErrNoRemoteAddrs
 	exitErr := defaultDialFail
 
 	defer s.limiter.clearAllPeerDials(p)