Added support for changing nicknames

src/Discord.Net/API/DiscordRawClient.cs

@@ -738,6 +738,13 @@ namespace Discord.API
 
             return await Send<User>("PATCH", "users/@me", args).ConfigureAwait(false);
         }
+        public async Task ModifyCurrentUserNick(ulong guildId, ModifyCurrentUserNickParams args)
+        {
+            if (args == null) throw new ArgumentNullException(nameof(args));
+            if (args.Nickname == "") throw new ArgumentOutOfRangeException(nameof(args.Nickname));
+
+            await Send("PATCH", $"guilds/{guildId}/members/@me/nick", args).ConfigureAwait(false);
+        }
         public async Task<Channel> CreateDMChannel(CreateDMChannelParams args)
         {
             if (args == null) throw new ArgumentNullException(nameof(args));

src/Discord.Net/API/Rest/ModifyCurrentUserNickParams.cs

@@ -0,0 +1,10 @@
+using Newtonsoft.Json;
+
+namespace Discord.API.Rest
+{
+    public class ModifyCurrentUserNickParams
+    {
+        [JsonProperty("nick")]
+        public string Nickname { get; set; }
+    }
+}

src/Discord.Net/Discord.Net.csproj

@@ -70,6 +70,7 @@
     <Compile Include="API\Optional.cs" />
     <Compile Include="API\Rest\DeleteMessagesParam.cs" />
     <Compile Include="API\Rest\GetGuildMembersParams.cs" />
+    <Compile Include="API\Rest\ModifyCurrentUserNickParams.cs" />
     <Compile Include="API\Rest\UploadFileParams.cs" />
     <Compile Include="API\Rest\GuildPruneParams.cs" />
     <Compile Include="API\Rest\CreateChannelInviteParams.cs" />

src/Discord.Net/Rest/Entities/Users/GuildUser.cs

@@ -83,15 +83,29 @@ namespace Discord.Rest
 
             var args = new ModifyGuildMemberParams();
             func(args);
-            await Discord.BaseClient.ModifyGuildMember(Guild.Id, Id, args).ConfigureAwait(false);
-            if (args.Deaf.IsSpecified)
-                IsDeaf = args.Deaf;
-            if (args.Mute.IsSpecified)
-                IsMute = args.Mute;
-            if (args.Nickname.IsSpecified)
-                Nickname = args.Nickname;
-            if (args.Roles.IsSpecified)
-                _roles = args.Roles.Value.Select(x => Guild.GetRole(x)).Where(x => x != null).ToImmutableArray();
+
+            bool isCurrentUser = IsCurrentUser;
+            if (isCurrentUser && args.Nickname.IsSpecified)
+            {
+                var nickArgs = new ModifyCurrentUserNickParams
+                {
+                    Nickname = args.Nickname.Value
+                };
+                await Discord.BaseClient.ModifyCurrentUserNick(Guild.Id, nickArgs).ConfigureAwait(false);
+            }
+
+            if (!isCurrentUser || args.Deaf.IsSpecified || args.Mute.IsSpecified || args.Roles.IsSpecified)
+            {
+                await Discord.BaseClient.ModifyGuildMember(Guild.Id, Id, args).ConfigureAwait(false);
+                if (args.Deaf.IsSpecified)
+                    IsDeaf = args.Deaf;
+                if (args.Mute.IsSpecified)
+                    IsMute = args.Mute;
+                if (args.Nickname.IsSpecified)
+                    Nickname = args.Nickname;
+                if (args.Roles.IsSpecified)
+                    _roles = args.Roles.Value.Select(x => Guild.GetRole(x)).Where(x => x != null).ToImmutableArray();
+            }
         }