Better error-message when bind fails.

runtime/bin/socket_patch.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 patch class RawServerSocket {
   /* patch */ static Future<RawServerSocket> bind(address,
                                                   int port,
                                                   {int backlog: 0,
                                                    bool v6Only: false,
                                                    bool shared: false}) {
@@ skipping 413 matching lines @@
             if (sourceAddress == null) {
               result = socket.nativeCreateConnect(address._in_addr, port);
             } else {
               assert(sourceAddress is _InternetAddress);
               result = socket.nativeCreateBindConnect(
                   address._in_addr, port, sourceAddress._in_addr);
             }
             if (result is OSError) {
               // Keep first error, if present.
               if (error == null) {
-                error = createError(result, "Connection failed", address, port);
+                int errorCode = result.errorCode;
+                if (errorCode != null && socket.isBindError(errorCode)) {
+                  error = createError(result, "Bind failed", sourceAddress);
+                } else {
+                  error =
+                      createError(result, "Connection failed", address, port);
+                }
               }
               connectNext();
             } else {
               // Query the local port, for error messages.
               socket.port;
               // Set up timer for when we should retry the next address
               // (if any).
               var duration = address.isLoopback ?
                   _RETRY_DURATION_LOOPBACK :
                   _RETRY_DURATION;
@@ skipping 623 matching lines @@
   nativeWrite(List<int> buffer, int offset, int bytes)
       native "Socket_WriteList";
   nativeSendTo(List<int> buffer, int offset, int bytes,
                List<int> address, int port)
       native "Socket_SendTo";
   nativeCreateConnect(List<int> addr,
                       int port) native "Socket_CreateConnect";
   nativeCreateBindConnect(
       List<int> addr, int port, List<int> sourceAddr)
       native "Socket_CreateBindConnect";
+  bool isBindError(int errorNumber) native "Socket_IsBindError";
   nativeCreateBindListen(List<int> addr, int port, int backlog, bool v6Only,
                          bool shared)
       native "ServerSocket_CreateBindListen";
   nativeCreateBindDatagram(List<int> addr, int port, bool reuseAddress)
       native "Socket_CreateBindDatagram";
   nativeAccept(_NativeSocket socket) native "ServerSocket_Accept";
   int nativeGetPort() native "Socket_GetPort";
   List nativeGetRemotePeer() native "Socket_GetRemotePeer";
   int nativeGetSocketId() native "Socket_GetSocketId";
   OSError nativeGetError() native "Socket_GetError";
@@ skipping 769 matching lines @@
 Datagram _makeDatagram(List<int> data,
                        String address,
                        List<int> in_addr,
                        int port) {
   return new Datagram(
       data,
       new _InternetAddress(address, null, in_addr),
       port);
 }