From cafa53790e478a7083c591d5ae48b81519f1f590 Mon Sep 17 00:00:00 2001
From: Chris Johnston <chris@thejohnstons.net>
Date: Tue, 27 Mar 2018 00:44:13 -0700
Subject: [PATCH 01/20] Fix #995 ICategoryChannel.CategoryID throws
 NotSupportedException

---
 src/Discord.Net.Rest/Entities/Channels/RestCategoryChannel.cs | 4 +++-
 .../Entities/Channels/SocketCategoryChannel.cs                | 2 ++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/Discord.Net.Rest/Entities/Channels/RestCategoryChannel.cs b/src/Discord.Net.Rest/Entities/Channels/RestCategoryChannel.cs
index 397e14e768..2a89edb371 100644
--- a/src/Discord.Net.Rest/Entities/Channels/RestCategoryChannel.cs
+++ b/src/Discord.Net.Rest/Entities/Channels/RestCategoryChannel.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
@@ -25,6 +25,8 @@ internal new static RestCategoryChannel Create(BaseDiscordClient discord, IGuild
         private string DebuggerDisplay => $"{Name} ({Id}, Category)";
 
         // IGuildChannel
+        ulong? IGuildChannel.CategoryId
+            => throw new NotSupportedException();
         IAsyncEnumerable<IReadOnlyCollection<IGuildUser>> IGuildChannel.GetUsersAsync(CacheMode mode, RequestOptions options)
             => throw new NotSupportedException();
         Task<IGuildUser> IGuildChannel.GetUserAsync(ulong id, CacheMode mode, RequestOptions options)
diff --git a/src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs b/src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs
index e7a165c2f1..9986ebf9cf 100644
--- a/src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs
+++ b/src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs
@@ -51,6 +51,8 @@ public override SocketGuildUser GetUser(ulong id)
         internal new SocketCategoryChannel Clone() => MemberwiseClone() as SocketCategoryChannel;
 
         // IGuildChannel
+        ulong? IGuildChannel.CategoryId
+            => throw new NotSupportedException();
         IAsyncEnumerable<IReadOnlyCollection<IGuildUser>> IGuildChannel.GetUsersAsync(CacheMode mode, RequestOptions options)
             => ImmutableArray.Create<IReadOnlyCollection<IGuildUser>>(Users).ToAsyncEnumerable();
         Task<IGuildUser> IGuildChannel.GetUserAsync(ulong id, CacheMode mode, RequestOptions options)

From 0613b8d6948ef8486373806ed09ea66485599b81 Mon Sep 17 00:00:00 2001
From: Chris Johnston <chris@thejohnstons.net>
Date: Tue, 27 Mar 2018 00:58:32 -0700
Subject: [PATCH 02/20] Add tests

---
 test/Discord.Net.Tests/Tests.Channels.cs | 31 +++++++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/test/Discord.Net.Tests/Tests.Channels.cs b/test/Discord.Net.Tests/Tests.Channels.cs
index b528ca5fb5..6506dfd9e8 100644
--- a/test/Discord.Net.Tests/Tests.Channels.cs
+++ b/test/Discord.Net.Tests/Tests.Channels.cs
@@ -1,4 +1,5 @@
 using Discord.Rest;
+using System;
 using System.Linq;
 using System.Threading.Tasks;
 using Xunit;
@@ -140,5 +141,33 @@ private static void CheckVoiceChannels(params RestVoiceChannel[] voiceChannels)
             Assert.Equal(voice3.Position, 1);
             Assert.Equal(voice3.UserLimit, 16);
         }
+
+        [Fact]
+        public async Task TestChannelCategories()
+        {
+            CheckChannelCategories(_client, _guild);
+        }
+
+        private async static void CheckChannelCategories(DiscordRestClient client, RestGuild guild)
+        {
+            // create some channel categories
+            var cat1 = await guild.CreateCategoryChannelAsync("Cat1");
+            var cat2 = await guild.CreateCategoryChannelAsync("Cat2");
+
+            // check that both CategoryID and GetCategoryID throw NotSupportedException
+            // because Categories cannot be nested
+            Assert.Throws<NotSupportedException>(() =>
+            {
+                var x = cat1.CategoryId;
+            });
+
+            Assert.Throws<NotSupportedException>(() =>
+            {
+                var x = cat2.GetCategoryAsync();
+            });
+
+
+            // incomplete test, could use more coverage
+        }
     }
-}
\ No newline at end of file
+}

From dca85f12df5690bce8df9d90926edc779466375d Mon Sep 17 00:00:00 2001
From: Chris Johnston <chris@thejohnstons.net>
Date: Tue, 27 Mar 2018 01:01:15 -0700
Subject: [PATCH 03/20] change run mode of TestChannelCategories

---
 test/Discord.Net.Tests/Tests.Channels.cs | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/test/Discord.Net.Tests/Tests.Channels.cs b/test/Discord.Net.Tests/Tests.Channels.cs
index 6506dfd9e8..7c1612a5e1 100644
--- a/test/Discord.Net.Tests/Tests.Channels.cs
+++ b/test/Discord.Net.Tests/Tests.Channels.cs
@@ -143,9 +143,11 @@ private static void CheckVoiceChannels(params RestVoiceChannel[] voiceChannels)
         }
 
         [Fact]
-        public async Task TestChannelCategories()
+        public Task TestChannelCategories()
         {
             CheckChannelCategories(_client, _guild);
+
+            return Task.CompletedTask;
         }
 
         private async static void CheckChannelCategories(DiscordRestClient client, RestGuild guild)
@@ -166,8 +168,7 @@ private async static void CheckChannelCategories(DiscordRestClient client, RestG
                 var x = cat2.GetCategoryAsync();
             });
 
-
-            // incomplete test, could use more coverage
+            // incomplete test, could use more coverage, incluing behavior of nested Text and Voice channels
         }
     }
 }

From 6ca9632a628e542e24682a5f5d1cdfb4c25eda46 Mon Sep 17 00:00:00 2001
From: Chris Johnston <chris@thejohnstons.net>
Date: Tue, 27 Mar 2018 01:12:47 -0700
Subject: [PATCH 04/20] Add throw for GetCategoryAsync

---
 src/Discord.Net.Rest/Entities/Channels/RestCategoryChannel.cs   | 2 ++
 .../Entities/Channels/SocketCategoryChannel.cs                  | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/src/Discord.Net.Rest/Entities/Channels/RestCategoryChannel.cs b/src/Discord.Net.Rest/Entities/Channels/RestCategoryChannel.cs
index 2a89edb371..bfcfa1a928 100644
--- a/src/Discord.Net.Rest/Entities/Channels/RestCategoryChannel.cs
+++ b/src/Discord.Net.Rest/Entities/Channels/RestCategoryChannel.cs
@@ -27,6 +27,8 @@ internal new static RestCategoryChannel Create(BaseDiscordClient discord, IGuild
         // IGuildChannel
         ulong? IGuildChannel.CategoryId
             => throw new NotSupportedException();
+        Task<ICategoryChannel> IGuildChannel.GetCategoryAsync()
+            => throw new NotSupportedException();
         IAsyncEnumerable<IReadOnlyCollection<IGuildUser>> IGuildChannel.GetUsersAsync(CacheMode mode, RequestOptions options)
             => throw new NotSupportedException();
         Task<IGuildUser> IGuildChannel.GetUserAsync(ulong id, CacheMode mode, RequestOptions options)
diff --git a/src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs b/src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs
index 9986ebf9cf..384620d222 100644
--- a/src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs
+++ b/src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs
@@ -53,6 +53,8 @@ public override SocketGuildUser GetUser(ulong id)
         // IGuildChannel
         ulong? IGuildChannel.CategoryId
             => throw new NotSupportedException();
+        Task<ICategoryChannel> IGuildChannel.GetCategoryAsync()
+            => throw new NotSupportedException();
         IAsyncEnumerable<IReadOnlyCollection<IGuildUser>> IGuildChannel.GetUsersAsync(CacheMode mode, RequestOptions options)
             => ImmutableArray.Create<IReadOnlyCollection<IGuildUser>>(Users).ToAsyncEnumerable();
         Task<IGuildUser> IGuildChannel.GetUserAsync(ulong id, CacheMode mode, RequestOptions options)

From f9c67074e0fe8f048f1c708a6120edc05ee0a41b Mon Sep 17 00:00:00 2001
From: Chris Johnston <chris@thejohnstons.net>
Date: Tue, 27 Mar 2018 01:27:49 -0700
Subject: [PATCH 05/20] Add xml doc explaining why exception is thrown

---
 .../Entities/Channels/RestCategoryChannel.cs             | 9 +++++++++
 .../Entities/Channels/SocketCategoryChannel.cs           | 9 +++++++++
 2 files changed, 18 insertions(+)

diff --git a/src/Discord.Net.Rest/Entities/Channels/RestCategoryChannel.cs b/src/Discord.Net.Rest/Entities/Channels/RestCategoryChannel.cs
index bfcfa1a928..bfdf1f6c0d 100644
--- a/src/Discord.Net.Rest/Entities/Channels/RestCategoryChannel.cs
+++ b/src/Discord.Net.Rest/Entities/Channels/RestCategoryChannel.cs
@@ -25,8 +25,17 @@ internal new static RestCategoryChannel Create(BaseDiscordClient discord, IGuild
         private string DebuggerDisplay => $"{Name} ({Id}, Category)";
 
         // IGuildChannel
+
+        /// <summary>
+        /// Throws a NotSupportedException because Channel Categories cannot be the child of another Channel Category.
+        /// </summary>
+        /// <exception cref="NotSupportedException">A NotSupportedException is always thrown because Channel Categories do not support being nested.</exception>
         ulong? IGuildChannel.CategoryId
             => throw new NotSupportedException();
+        /// <summary>
+        /// Throws a NotSupportedException because Channel Categories cannot be the child of another Channel Category.
+        /// </summary>
+        /// <exception cref="NotSupportedException">A NotSupportedException is always thrown because Channel Categories do not support being nested.</exception>
         Task<ICategoryChannel> IGuildChannel.GetCategoryAsync()
             => throw new NotSupportedException();
         IAsyncEnumerable<IReadOnlyCollection<IGuildUser>> IGuildChannel.GetUsersAsync(CacheMode mode, RequestOptions options)
diff --git a/src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs b/src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs
index 384620d222..e53273ec9f 100644
--- a/src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs
+++ b/src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs
@@ -51,8 +51,17 @@ public override SocketGuildUser GetUser(ulong id)
         internal new SocketCategoryChannel Clone() => MemberwiseClone() as SocketCategoryChannel;
 
         // IGuildChannel
+
+        /// <summary>
+        /// Throws a NotSupportedException because Channel Categories cannot be the child of another Channel Category.
+        /// </summary>
+        /// <exception cref="NotSupportedException">A NotSupportedException is always thrown because Channel Categories do not support being nested.</exception>
         ulong? IGuildChannel.CategoryId
             => throw new NotSupportedException();
+        /// <summary>
+        /// Throws a NotSupportedException because Channel Categories cannot be the child of another Channel Category.
+        /// </summary>
+        /// <exception cref="NotSupportedException">A NotSupportedException is always thrown because Channel Categories do not support being nested.</exception>
         Task<ICategoryChannel> IGuildChannel.GetCategoryAsync()
             => throw new NotSupportedException();
         IAsyncEnumerable<IReadOnlyCollection<IGuildUser>> IGuildChannel.GetUsersAsync(CacheMode mode, RequestOptions options)

From cb392db30c7525fb351f4069d866f9d49b60a8de Mon Sep 17 00:00:00 2001
From: Chris Johnston <chris@thejohnstons.net>
Date: Tue, 27 Mar 2018 01:45:37 -0700
Subject: [PATCH 06/20] Add test coverage for text and voice channel categories

---
 test/Discord.Net.Tests/Tests.Channels.cs | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/test/Discord.Net.Tests/Tests.Channels.cs b/test/Discord.Net.Tests/Tests.Channels.cs
index 7c1612a5e1..512a1ef4e2 100644
--- a/test/Discord.Net.Tests/Tests.Channels.cs
+++ b/test/Discord.Net.Tests/Tests.Channels.cs
@@ -168,7 +168,29 @@ private async static void CheckChannelCategories(DiscordRestClient client, RestG
                 var x = cat2.GetCategoryAsync();
             });
 
-            // incomplete test, could use more coverage, incluing behavior of nested Text and Voice channels
+            var text1 = await guild.CreateTextChannelAsync("nestedText1");
+            var voice1 = await guild.CreateVoiceChannelAsync("nestedVoice1");
+            // set the text channel parent to Cat 1
+            await text1.ModifyAsync(x =>
+            {
+                x.CategoryId = cat1.Id;
+            });
+
+            await voice1.ModifyAsync(x =>
+            {
+                x.CategoryId = cat2.Id;
+            });
+
+            // these shouldn't throw because they are not channel categories
+
+            // assert that CategoryId works for text channels
+            Assert.Equal(text1.CategoryId, cat1.Id);
+            Assert.Equal((await text1.GetCategoryAsync()).Id, cat1.Id);
+            // and for voice channels
+            Assert.Equal(voice1.CategoryId, cat2.Id);
+            Assert.Equal((await voice1.GetCategoryAsync()).Id, cat2.Id);
+
+            // incomplete test, could use more coverage of other methods
         }
     }
 }

From 8bb92ccbfe6a7e95df4571c2d0dee80db272fc08 Mon Sep 17 00:00:00 2001
From: Chris Johnston <chris@thejohnstons.net>
Date: Wed, 28 Mar 2018 00:44:39 -0700
Subject: [PATCH 07/20] initial implementation of INestedChannel

---
 .../Entities/Channels/ICategoryChannel.cs     |  2 +-
 .../Entities/Channels/IGuildChannel.cs        |  8 ++------
 .../Entities/Channels/INestedChannel.cs       | 20 +++++++++++++++++++
 .../Entities/Channels/ITextChannel.cs         |  6 +++---
 .../Entities/Channels/RestCategoryChannel.cs  | 17 ----------------
 .../Entities/Channels/RestGuildChannel.cs     | 10 +---------
 .../Entities/Channels/RestTextChannel.cs      | 11 +++++++++-
 .../Entities/Channels/RestVoiceChannel.cs     | 13 ++++++++++--
 .../Entities/Channels/SocketTextChannel.cs    |  9 ++++++++-
 .../Entities/Channels/SocketVoiceChannel.cs   | 11 ++++++++--
 10 files changed, 65 insertions(+), 42 deletions(-)
 create mode 100644 src/Discord.Net.Core/Entities/Channels/INestedChannel.cs

diff --git a/src/Discord.Net.Core/Entities/Channels/ICategoryChannel.cs b/src/Discord.Net.Core/Entities/Channels/ICategoryChannel.cs
index 0f7f5aa62d..c004cafd5e 100644
--- a/src/Discord.Net.Core/Entities/Channels/ICategoryChannel.cs
+++ b/src/Discord.Net.Core/Entities/Channels/ICategoryChannel.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
diff --git a/src/Discord.Net.Core/Entities/Channels/IGuildChannel.cs b/src/Discord.Net.Core/Entities/Channels/IGuildChannel.cs
index c9841cb15c..6514d46cd9 100644
--- a/src/Discord.Net.Core/Entities/Channels/IGuildChannel.cs
+++ b/src/Discord.Net.Core/Entities/Channels/IGuildChannel.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Threading.Tasks;
 
@@ -9,10 +9,6 @@ public interface IGuildChannel : IChannel, IDeletable
         /// <summary> Gets the position of this channel in the guild's channel list, relative to others of the same type. </summary>
         int Position { get; }
 
-        /// <summary> Gets the parentid (category) of this channel in the guild's channel list. </summary>
-        ulong? CategoryId { get; }
-        /// <summary> Gets the parent channel (category) of this channel. </summary>
-        Task<ICategoryChannel> GetCategoryAsync();
         /// <summary> Gets the guild this channel is a member of. </summary>
         IGuild Guild { get; }
         /// <summary> Gets the id of the guild this channel is a member of. </summary>
@@ -49,4 +45,4 @@ public interface IGuildChannel : IChannel, IDeletable
         /// <summary> Gets a user in this channel with the provided id.</summary>
         new Task<IGuildUser> GetUserAsync(ulong id, CacheMode mode = CacheMode.AllowDownload, RequestOptions options = null);
     }
-}
\ No newline at end of file
+}
diff --git a/src/Discord.Net.Core/Entities/Channels/INestedChannel.cs b/src/Discord.Net.Core/Entities/Channels/INestedChannel.cs
new file mode 100644
index 0000000000..7e9d8fbf03
--- /dev/null
+++ b/src/Discord.Net.Core/Entities/Channels/INestedChannel.cs
@@ -0,0 +1,20 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Discord
+{
+    /// <summary>
+    /// A type of guild channel that can be nested within a category.
+    /// Contains a CategoryId that is set to the parent category, if it is set.
+    /// </summary>
+    public interface INestedChannel : IGuildChannel
+    {
+        /// <summary> Gets the parentid (category) of this channel in the guild's channel list. </summary>
+        ulong? CategoryId { get; }
+        /// <summary> Gets the parent channel (category) of this channel, if it is set. If unset, returns null.</summary>
+        Task<ICategoryChannel> GetCategoryAsync();
+    }
+}
diff --git a/src/Discord.Net.Core/Entities/Channels/ITextChannel.cs b/src/Discord.Net.Core/Entities/Channels/ITextChannel.cs
index 7c6ec39081..ae15ce2bae 100644
--- a/src/Discord.Net.Core/Entities/Channels/ITextChannel.cs
+++ b/src/Discord.Net.Core/Entities/Channels/ITextChannel.cs
@@ -1,11 +1,11 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Threading.Tasks;
 
 namespace Discord
 {
-    public interface ITextChannel : IMessageChannel, IMentionable, IGuildChannel
+    public interface ITextChannel : IMessageChannel, IMentionable, IGuildChannel, INestedChannel
     {
         /// <summary> Checks if the channel is NSFW. </summary>
         bool IsNsfw { get; }
@@ -28,4 +28,4 @@ public interface ITextChannel : IMessageChannel, IMentionable, IGuildChannel
         /// <summary> Gets the webhooks for this text channel. </summary>
         Task<IReadOnlyCollection<IWebhook>> GetWebhooksAsync(RequestOptions options = null);
     }
-}
\ No newline at end of file
+}
diff --git a/src/Discord.Net.Rest/Entities/Channels/RestCategoryChannel.cs b/src/Discord.Net.Rest/Entities/Channels/RestCategoryChannel.cs
index bfdf1f6c0d..321f1f1d24 100644
--- a/src/Discord.Net.Rest/Entities/Channels/RestCategoryChannel.cs
+++ b/src/Discord.Net.Rest/Entities/Channels/RestCategoryChannel.cs
@@ -25,23 +25,6 @@ internal new static RestCategoryChannel Create(BaseDiscordClient discord, IGuild
         private string DebuggerDisplay => $"{Name} ({Id}, Category)";
 
         // IGuildChannel
-
-        /// <summary>
-        /// Throws a NotSupportedException because Channel Categories cannot be the child of another Channel Category.
-        /// </summary>
-        /// <exception cref="NotSupportedException">A NotSupportedException is always thrown because Channel Categories do not support being nested.</exception>
-        ulong? IGuildChannel.CategoryId
-            => throw new NotSupportedException();
-        /// <summary>
-        /// Throws a NotSupportedException because Channel Categories cannot be the child of another Channel Category.
-        /// </summary>
-        /// <exception cref="NotSupportedException">A NotSupportedException is always thrown because Channel Categories do not support being nested.</exception>
-        Task<ICategoryChannel> IGuildChannel.GetCategoryAsync()
-            => throw new NotSupportedException();
-        IAsyncEnumerable<IReadOnlyCollection<IGuildUser>> IGuildChannel.GetUsersAsync(CacheMode mode, RequestOptions options)
-            => throw new NotSupportedException();
-        Task<IGuildUser> IGuildChannel.GetUserAsync(ulong id, CacheMode mode, RequestOptions options)
-            => throw new NotSupportedException();
         Task<IInviteMetadata> IGuildChannel.CreateInviteAsync(int? maxAge, int? maxUses, bool isTemporary, bool isUnique, RequestOptions options)
             => throw new NotSupportedException();
         Task<IReadOnlyCollection<IInviteMetadata>> IGuildChannel.GetInvitesAsync(RequestOptions options)
diff --git a/src/Discord.Net.Rest/Entities/Channels/RestGuildChannel.cs b/src/Discord.Net.Rest/Entities/Channels/RestGuildChannel.cs
index 026d03cc83..8bddcff09e 100644
--- a/src/Discord.Net.Rest/Entities/Channels/RestGuildChannel.cs
+++ b/src/Discord.Net.Rest/Entities/Channels/RestGuildChannel.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Linq;
@@ -16,7 +16,6 @@ public class RestGuildChannel : RestChannel, IGuildChannel, IUpdateable
         internal IGuild Guild { get; }
         public string Name { get; private set; }
         public int Position { get; private set; }
-        public ulong? CategoryId { get; private set; }
         public ulong GuildId => Guild.Id;
 
         internal RestGuildChannel(BaseDiscordClient discord, IGuild guild, ulong id)
@@ -64,13 +63,6 @@ public async Task ModifyAsync(Action<GuildChannelProperties> func, RequestOption
         public Task DeleteAsync(RequestOptions options = null)
             => ChannelHelper.DeleteAsync(this, Discord, options);
 
-        public async Task<ICategoryChannel> GetCategoryAsync()
-        {
-            if (CategoryId.HasValue)
-                return (await Guild.GetChannelAsync(CategoryId.Value).ConfigureAwait(false)) as ICategoryChannel;
-            return null;
-        }
-
         public OverwritePermissions? GetPermissionOverwrite(IUser user)
         {
             for (int i = 0; i < _overwrites.Length; i++)
diff --git a/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs b/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs
index 600b197d61..18af4939ac 100644
--- a/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs
+++ b/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs
@@ -9,9 +9,10 @@
 namespace Discord.Rest
 {
     [DebuggerDisplay(@"{DebuggerDisplay,nq}")]
-    public class RestTextChannel : RestGuildChannel, IRestMessageChannel, ITextChannel
+    public class RestTextChannel : RestGuildChannel, IRestMessageChannel, ITextChannel, INestedChannel
     {
         public string Topic { get; private set; }
+        public ulong? CategoryId { get; private set; }
 
         public string Mention => MentionUtils.MentionChannel(Id);
 
@@ -168,5 +169,13 @@ IAsyncEnumerable<IReadOnlyCollection<IUser>> IChannel.GetUsersAsync(CacheMode mo
             else
                 return AsyncEnumerable.Empty<IReadOnlyCollection<IGuildUser>>();
         }
+
+        // INestedChannel
+        async Task<ICategoryChannel> INestedChannel.GetCategoryAsync()
+        {
+            if (CategoryId.HasValue)
+                return (await Guild.GetChannelAsync(CategoryId.Value).ConfigureAwait(false)) as ICategoryChannel;
+            return null;
+        }
     }
 }
diff --git a/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs b/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs
index 300ebd08d5..53a28eaeea 100644
--- a/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs
+++ b/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs
@@ -1,4 +1,4 @@
-using Discord.Audio;
+using Discord.Audio;
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
@@ -9,10 +9,11 @@
 namespace Discord.Rest
 {
     [DebuggerDisplay(@"{DebuggerDisplay,nq}")]
-    public class RestVoiceChannel : RestGuildChannel, IVoiceChannel, IRestAudioChannel
+    public class RestVoiceChannel : RestGuildChannel, IVoiceChannel, IRestAudioChannel, INestedChannel
     {
         public int Bitrate { get; private set; }
         public int? UserLimit { get; private set; }
+        public ulong? CategoryId { get; private set; }
 
         internal RestVoiceChannel(BaseDiscordClient discord, IGuild guild, ulong id)
             : base(discord, guild, id)
@@ -48,5 +49,13 @@ Task<IGuildUser> IGuildChannel.GetUserAsync(ulong id, CacheMode mode, RequestOpt
             => Task.FromResult<IGuildUser>(null);
         IAsyncEnumerable<IReadOnlyCollection<IGuildUser>> IGuildChannel.GetUsersAsync(CacheMode mode, RequestOptions options)
             => AsyncEnumerable.Empty<IReadOnlyCollection<IGuildUser>>();
+
+        // INestedChannel
+        async Task<ICategoryChannel> INestedChannel.GetCategoryAsync()
+        {
+            if (CategoryId.HasValue)
+                return (await Guild.GetChannelAsync(CategoryId.Value).ConfigureAwait(false)) as ICategoryChannel;
+            return null;
+        }
     }
 }
diff --git a/src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs b/src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs
index ec7615b55e..b94ded5fbd 100644
--- a/src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs
+++ b/src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs
@@ -11,11 +11,14 @@
 namespace Discord.WebSocket
 {
     [DebuggerDisplay(@"{DebuggerDisplay,nq}")]
-    public class SocketTextChannel : SocketGuildChannel, ITextChannel, ISocketMessageChannel
+    public class SocketTextChannel : SocketGuildChannel, ITextChannel, ISocketMessageChannel, INestedChannel
     {
         private readonly MessageCache _messages;
 
         public string Topic { get; private set; }
+        public ulong? CategoryId { get; private set; }
+        public ICategoryChannel Category
+            => CategoryId.HasValue ? Guild.GetChannel(CategoryId.Value) as ICategoryChannel : null;
 
         private bool _nsfw;
         public bool IsNsfw => _nsfw || ChannelHelper.IsNsfw(this);
@@ -164,5 +167,9 @@ async Task<IUserMessage> IMessageChannel.SendMessageAsync(string text, bool isTT
             => await SendMessageAsync(text, isTTS, embed, options).ConfigureAwait(false);
         IDisposable IMessageChannel.EnterTypingState(RequestOptions options)
             => EnterTypingState(options);
+
+        // INestedChannel
+        Task<ICategoryChannel> INestedChannel.GetCategoryAsync()
+            => Task.FromResult(Category);
     }
 }
diff --git a/src/Discord.Net.WebSocket/Entities/Channels/SocketVoiceChannel.cs b/src/Discord.Net.WebSocket/Entities/Channels/SocketVoiceChannel.cs
index e8a6698458..a8ec9457aa 100644
--- a/src/Discord.Net.WebSocket/Entities/Channels/SocketVoiceChannel.cs
+++ b/src/Discord.Net.WebSocket/Entities/Channels/SocketVoiceChannel.cs
@@ -1,4 +1,4 @@
-using Discord.Audio;
+using Discord.Audio;
 using Discord.Rest;
 using System;
 using System.Collections.Generic;
@@ -11,10 +11,13 @@
 namespace Discord.WebSocket
 {
     [DebuggerDisplay(@"{DebuggerDisplay,nq}")]
-    public class SocketVoiceChannel : SocketGuildChannel, IVoiceChannel, ISocketAudioChannel
+    public class SocketVoiceChannel : SocketGuildChannel, IVoiceChannel, ISocketAudioChannel, INestedChannel
     {
         public int Bitrate { get; private set; }
         public int? UserLimit { get; private set; }
+        public ulong? CategoryId { get; private set; }
+        public ICategoryChannel Category
+            => CategoryId.HasValue ? Guild.GetChannel(CategoryId.Value) as ICategoryChannel : null;
 
         public override IReadOnlyCollection<SocketGuildUser> Users
             => Guild.Users.Where(x => x.VoiceChannel?.Id == Id).ToImmutableArray();
@@ -61,5 +64,9 @@ Task<IGuildUser> IGuildChannel.GetUserAsync(ulong id, CacheMode mode, RequestOpt
             => Task.FromResult<IGuildUser>(GetUser(id));
         IAsyncEnumerable<IReadOnlyCollection<IGuildUser>> IGuildChannel.GetUsersAsync(CacheMode mode, RequestOptions options)
             => ImmutableArray.Create<IReadOnlyCollection<IGuildUser>>(Users).ToAsyncEnumerable();
+
+        // INestedChannel
+        Task<ICategoryChannel> INestedChannel.GetCategoryAsync()
+            => Task.FromResult(Category);
     }
 }

From de84fcf4930773db83b140b16e05e4215a9039ec Mon Sep 17 00:00:00 2001
From: Chris Johnston <chris@thejohnstons.net>
Date: Wed, 28 Mar 2018 01:43:02 -0700
Subject: [PATCH 08/20] more implementation of INestedChannel design

---
 .../Entities/Channels/INestedChannel.cs       |  4 ----
 .../Entities/Channels/ChannelHelper.cs        | 10 ++++++++++
 .../Entities/Channels/RestTextChannel.cs      |  8 ++++++--
 .../Entities/Channels/RestVoiceChannel.cs     |  3 +++
 .../Channels/SocketCategoryChannel.cs         | 15 +--------------
 .../Entities/Channels/SocketGuildChannel.cs   | 13 +++----------
 .../Entities/Channels/SocketTextChannel.cs    |  6 +++++-
 .../Entities/Channels/SocketVoiceChannel.cs   |  7 +++++--
 test/Discord.Net.Tests/Tests.Channels.cs      | 19 +++++++------------
 9 files changed, 40 insertions(+), 45 deletions(-)

diff --git a/src/Discord.Net.Core/Entities/Channels/INestedChannel.cs b/src/Discord.Net.Core/Entities/Channels/INestedChannel.cs
index 7e9d8fbf03..4082bfbb2b 100644
--- a/src/Discord.Net.Core/Entities/Channels/INestedChannel.cs
+++ b/src/Discord.Net.Core/Entities/Channels/INestedChannel.cs
@@ -1,7 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
 using System.Threading.Tasks;
 
 namespace Discord
diff --git a/src/Discord.Net.Rest/Entities/Channels/ChannelHelper.cs b/src/Discord.Net.Rest/Entities/Channels/ChannelHelper.cs
index 6784f7f6a9..e82d0fecf4 100644
--- a/src/Discord.Net.Rest/Entities/Channels/ChannelHelper.cs
+++ b/src/Discord.Net.Rest/Entities/Channels/ChannelHelper.cs
@@ -313,6 +313,16 @@ public static async Task<IReadOnlyCollection<RestWebhook>> GetWebhooksAsync(ITex
             return models.Select(x => RestWebhook.Create(client, channel, x))
                 .ToImmutableArray();
         }
+        // Categories
+        public static async Task<ICategoryChannel> GetCategoryAsync(INestedChannel channel, BaseDiscordClient client, RequestOptions options)
+        {
+            // if no category id specified, return null
+            if (!channel.CategoryId.HasValue)
+                return null;
+            // CategoryId will contain a value here
+            var model = await client.ApiClient.GetChannelAsync(channel.CategoryId.Value, options).ConfigureAwait(false);
+            return RestCategoryChannel.Create(client, model) as ICategoryChannel;
+        }
 
         //Helpers
         private static IUser GetAuthor(BaseDiscordClient client, IGuild guild, UserModel model, ulong? webhookId)
diff --git a/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs b/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs
index 18af4939ac..d597efa9aa 100644
--- a/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs
+++ b/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs
@@ -32,7 +32,7 @@ internal new static RestTextChannel Create(BaseDiscordClient discord, IGuild gui
         internal override void Update(Model model)
         {
             base.Update(model);
-
+            CategoryId = model.CategoryId;
             Topic = model.Topic.Value;
             _nsfw = model.Nsfw.GetValueOrDefault();
         }
@@ -47,7 +47,7 @@ public Task<RestGuildUser> GetUserAsync(ulong id, RequestOptions options = null)
             => ChannelHelper.GetUserAsync(this, Guild, Discord, id, options);
         public IAsyncEnumerable<IReadOnlyCollection<RestGuildUser>> GetUsersAsync(RequestOptions options = null)
             => ChannelHelper.GetUsersAsync(this, Guild, Discord, null, null, options);
-
+        
         public Task<RestMessage> GetMessageAsync(ulong id, RequestOptions options = null)
             => ChannelHelper.GetMessageAsync(this, Discord, id, options);
         public IAsyncEnumerable<IReadOnlyCollection<RestMessage>> GetMessagesAsync(int limit = DiscordConfig.MaxMessagesPerBatch, RequestOptions options = null)
@@ -84,6 +84,9 @@ public Task<RestWebhook> GetWebhookAsync(ulong id, RequestOptions options = null
             => ChannelHelper.GetWebhookAsync(this, Discord, id, options);
         public Task<IReadOnlyCollection<RestWebhook>> GetWebhooksAsync(RequestOptions options = null)
             => ChannelHelper.GetWebhooksAsync(this, Discord, options);
+    
+        public Task<ICategoryChannel> GetCategoryAsync(RequestOptions options = null)
+            => ChannelHelper.GetCategoryAsync(this, Discord, options);
 
         private string DebuggerDisplay => $"{Name} ({Id}, Text)";
 
@@ -110,6 +113,7 @@ IAsyncEnumerable<IReadOnlyCollection<IMessage>> IMessageChannel.GetMessagesAsync
             else
                 return AsyncEnumerable.Empty<IReadOnlyCollection<IMessage>>();
         }
+        
         IAsyncEnumerable<IReadOnlyCollection<IMessage>> IMessageChannel.GetMessagesAsync(ulong fromMessageId, Direction dir, int limit, CacheMode mode, RequestOptions options)
         {
             if (mode == CacheMode.AllowDownload)
diff --git a/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs b/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs
index 53a28eaeea..05bc480b54 100644
--- a/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs
+++ b/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs
@@ -39,6 +39,9 @@ public async Task ModifyAsync(Action<VoiceChannelProperties> func, RequestOption
             Update(model);
         }
 
+        public Task<ICategoryChannel> GetCategoryAsync(RequestOptions options = null)
+            => ChannelHelper.GetCategoryAsync(this, Discord, options);
+
         private string DebuggerDisplay => $"{Name} ({Id}, Voice)";
 
         //IAudioChannel
diff --git a/src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs b/src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs
index e53273ec9f..7b6619be6b 100644
--- a/src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs
+++ b/src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs
@@ -20,7 +20,7 @@ public override IReadOnlyCollection<SocketGuildUser> Users
                ChannelPermission.ViewChannel)).ToImmutableArray();
 
         public IReadOnlyCollection<SocketGuildChannel> Channels
-            => Guild.Channels.Where(x => x.CategoryId == Id).ToImmutableArray();
+            => Guild.Channels.Where(x => x is INestedChannel && (x as INestedChannel).CategoryId == Id).ToImmutableArray();
 
         internal SocketCategoryChannel(DiscordSocketClient discord, ulong id, SocketGuild guild)
             : base(discord, id, guild)
@@ -51,19 +51,6 @@ public override SocketGuildUser GetUser(ulong id)
         internal new SocketCategoryChannel Clone() => MemberwiseClone() as SocketCategoryChannel;
 
         // IGuildChannel
-
-        /// <summary>
-        /// Throws a NotSupportedException because Channel Categories cannot be the child of another Channel Category.
-        /// </summary>
-        /// <exception cref="NotSupportedException">A NotSupportedException is always thrown because Channel Categories do not support being nested.</exception>
-        ulong? IGuildChannel.CategoryId
-            => throw new NotSupportedException();
-        /// <summary>
-        /// Throws a NotSupportedException because Channel Categories cannot be the child of another Channel Category.
-        /// </summary>
-        /// <exception cref="NotSupportedException">A NotSupportedException is always thrown because Channel Categories do not support being nested.</exception>
-        Task<ICategoryChannel> IGuildChannel.GetCategoryAsync()
-            => throw new NotSupportedException();
         IAsyncEnumerable<IReadOnlyCollection<IGuildUser>> IGuildChannel.GetUsersAsync(CacheMode mode, RequestOptions options)
             => ImmutableArray.Create<IReadOnlyCollection<IGuildUser>>(Users).ToAsyncEnumerable();
         Task<IGuildUser> IGuildChannel.GetUserAsync(ulong id, CacheMode mode, RequestOptions options)
diff --git a/src/Discord.Net.WebSocket/Entities/Channels/SocketGuildChannel.cs b/src/Discord.Net.WebSocket/Entities/Channels/SocketGuildChannel.cs
index 2163daf554..bfcffa35f1 100644
--- a/src/Discord.Net.WebSocket/Entities/Channels/SocketGuildChannel.cs
+++ b/src/Discord.Net.WebSocket/Entities/Channels/SocketGuildChannel.cs
@@ -1,4 +1,4 @@
-using Discord.Rest;
+using Discord.Rest;
 using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
@@ -16,10 +16,7 @@ public class SocketGuildChannel : SocketChannel, IGuildChannel
 
         public SocketGuild Guild { get; }
         public string Name { get; private set; }
-        public int Position { get; private set; }
-        public ulong? CategoryId { get; private set; }
-        public ICategoryChannel Category 
-            => CategoryId.HasValue ? Guild.GetChannel(CategoryId.Value) as ICategoryChannel : null;
+        public int Position { get; private set; }        
 
         public IReadOnlyCollection<Overwrite> PermissionOverwrites => _overwrites;
         public new virtual IReadOnlyCollection<SocketGuildUser> Users => ImmutableArray.Create<SocketGuildUser>();
@@ -48,8 +45,7 @@ internal override void Update(ClientState state, Model model)
         {
             Name = model.Name.Value;
             Position = model.Position.Value;
-            CategoryId = model.CategoryId;
-
+            
             var overwrites = model.PermissionOverwrites.Value;
             var newOverwrites = ImmutableArray.CreateBuilder<Overwrite>(overwrites.Length);
             for (int i = 0; i < overwrites.Length; i++)
@@ -135,9 +131,6 @@ public async Task<RestInviteMetadata> CreateInviteAsync(int? maxAge = 86400, int
         IGuild IGuildChannel.Guild => Guild;
         ulong IGuildChannel.GuildId => Guild.Id;
 
-        Task<ICategoryChannel> IGuildChannel.GetCategoryAsync()
-            => Task.FromResult(Category);
-
         async Task<IReadOnlyCollection<IInviteMetadata>> IGuildChannel.GetInvitesAsync(RequestOptions options)
             => await GetInvitesAsync(options).ConfigureAwait(false);
         async Task<IInviteMetadata> IGuildChannel.CreateInviteAsync(int? maxAge, int? maxUses, bool isTemporary, bool isUnique, RequestOptions options)
diff --git a/src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs b/src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs
index b94ded5fbd..54d8e53ee4 100644
--- a/src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs
+++ b/src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs
@@ -45,7 +45,7 @@ internal new static SocketTextChannel Create(SocketGuild guild, ClientState stat
         internal override void Update(ClientState state, Model model)
         {
             base.Update(state, model);
-
+            CategoryId = model.CategoryId;
             Topic = model.Topic.Value;
             _nsfw = model.Nsfw.GetValueOrDefault();
         }
@@ -124,6 +124,10 @@ public Task<RestWebhook> GetWebhookAsync(ulong id, RequestOptions options = null
         public Task<IReadOnlyCollection<RestWebhook>> GetWebhooksAsync(RequestOptions options = null)
             => ChannelHelper.GetWebhooksAsync(this, Discord, options);
 
+        // Categories
+        public Task<ICategoryChannel> GetCategoryAsync(RequestOptions options = null)
+            => ChannelHelper.GetCategoryAsync(this, Discord, options);
+
         private string DebuggerDisplay => $"{Name} ({Id}, Text)";
         internal new SocketTextChannel Clone() => MemberwiseClone() as SocketTextChannel;
 
diff --git a/src/Discord.Net.WebSocket/Entities/Channels/SocketVoiceChannel.cs b/src/Discord.Net.WebSocket/Entities/Channels/SocketVoiceChannel.cs
index a8ec9457aa..45d68bd852 100644
--- a/src/Discord.Net.WebSocket/Entities/Channels/SocketVoiceChannel.cs
+++ b/src/Discord.Net.WebSocket/Entities/Channels/SocketVoiceChannel.cs
@@ -35,7 +35,7 @@ internal new static SocketVoiceChannel Create(SocketGuild guild, ClientState sta
         internal override void Update(ClientState state, Model model)
         {
             base.Update(state, model);
-
+            CategoryId = model.CategoryId;
             Bitrate = model.Bitrate.Value;
             UserLimit = model.UserLimit.Value != 0 ? model.UserLimit.Value : (int?)null;
         }
@@ -55,7 +55,10 @@ public override SocketGuildUser GetUser(ulong id)
                 return user;
             return null;
         }
-        
+
+        public Task<ICategoryChannel> GetCategoryAsync(RequestOptions options = null)
+            => ChannelHelper.GetCategoryAsync(this, Discord, options);
+
         private string DebuggerDisplay => $"{Name} ({Id}, Voice)";
         internal new SocketVoiceChannel Clone() => MemberwiseClone() as SocketVoiceChannel;
 
diff --git a/test/Discord.Net.Tests/Tests.Channels.cs b/test/Discord.Net.Tests/Tests.Channels.cs
index 512a1ef4e2..407241f8cd 100644
--- a/test/Discord.Net.Tests/Tests.Channels.cs
+++ b/test/Discord.Net.Tests/Tests.Channels.cs
@@ -156,18 +156,6 @@ private async static void CheckChannelCategories(DiscordRestClient client, RestG
             var cat1 = await guild.CreateCategoryChannelAsync("Cat1");
             var cat2 = await guild.CreateCategoryChannelAsync("Cat2");
 
-            // check that both CategoryID and GetCategoryID throw NotSupportedException
-            // because Categories cannot be nested
-            Assert.Throws<NotSupportedException>(() =>
-            {
-                var x = cat1.CategoryId;
-            });
-
-            Assert.Throws<NotSupportedException>(() =>
-            {
-                var x = cat2.GetCategoryAsync();
-            });
-
             var text1 = await guild.CreateTextChannelAsync("nestedText1");
             var voice1 = await guild.CreateVoiceChannelAsync("nestedVoice1");
             // set the text channel parent to Cat 1
@@ -185,10 +173,17 @@ private async static void CheckChannelCategories(DiscordRestClient client, RestG
 
             // assert that CategoryId works for text channels
             Assert.Equal(text1.CategoryId, cat1.Id);
+            Assert.True(text1 is INestedChannel);
+            Assert.Equal((await (text1 as INestedChannel).GetCategoryAsync()).Id, cat1.Id);
             Assert.Equal((await text1.GetCategoryAsync()).Id, cat1.Id);
+            Assert.Equal(text1.CategoryId, cat1.Id);
+
             // and for voice channels
             Assert.Equal(voice1.CategoryId, cat2.Id);
+            Assert.True(voice1 is INestedChannel);
+            Assert.Equal((await (voice1 as INestedChannel).GetCategoryAsync()).Id, cat2.Id);
             Assert.Equal((await voice1.GetCategoryAsync()).Id, cat2.Id);
+            Assert.Equal(voice1.CategoryId, cat1.Id);
 
             // incomplete test, could use more coverage of other methods
         }

From ba2a58914dda95e38fc198994fcbfefc297b875b Mon Sep 17 00:00:00 2001
From: Chris Johnston <chris@thejohnstons.net>
Date: Wed, 28 Mar 2018 02:50:28 -0700
Subject: [PATCH 09/20] Add case in RestChannel Create for Category type

---
 src/Discord.Net.Rest/Entities/Channels/RestChannel.cs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/Discord.Net.Rest/Entities/Channels/RestChannel.cs b/src/Discord.Net.Rest/Entities/Channels/RestChannel.cs
index 04cc5a9378..5860d82839 100644
--- a/src/Discord.Net.Rest/Entities/Channels/RestChannel.cs
+++ b/src/Discord.Net.Rest/Entities/Channels/RestChannel.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
@@ -24,6 +24,8 @@ internal static RestChannel Create(BaseDiscordClient discord, Model model)
                 case ChannelType.DM:
                 case ChannelType.Group:
                     return CreatePrivate(discord, model) as RestChannel;
+                case ChannelType.Category:
+                    return RestCategoryChannel.Create(discord, new RestGuild(discord, model.GuildId.Value), model);
                 default:
                     return new RestChannel(discord, model.Id);
             }

From 52739e4838e3fecaed780886da79bea607c33f33 Mon Sep 17 00:00:00 2001
From: Chris Johnston <chris@thejohnstons.net>
Date: Thu, 29 Mar 2018 20:18:18 -0700
Subject: [PATCH 10/20] set the CategoryID for RestVoiceChannel

---
 src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs b/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs
index 05bc480b54..870876ee00 100644
--- a/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs
+++ b/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs
@@ -28,7 +28,7 @@ internal new static RestVoiceChannel Create(BaseDiscordClient discord, IGuild gu
         internal override void Update(Model model)
         {
             base.Update(model);
-
+            CategoryId = model.CategoryId;
             Bitrate = model.Bitrate.Value;
             UserLimit = model.UserLimit.Value != 0 ? model.UserLimit.Value : (int?)null;
         }

From bf7c4dc8a721339e910a28c1c6532e73b1e77f19 Mon Sep 17 00:00:00 2001
From: Chris Johnston <chris@thejohnstons.net>
Date: Thu, 29 Mar 2018 20:20:11 -0700
Subject: [PATCH 11/20] rewrite channel category tests to work with existing
 pattern

---
 test/Discord.Net.Tests/Tests.Channels.cs | 87 ++++++++++++++++--------
 1 file changed, 57 insertions(+), 30 deletions(-)

diff --git a/test/Discord.Net.Tests/Tests.Channels.cs b/test/Discord.Net.Tests/Tests.Channels.cs
index 407241f8cd..46a3a81815 100644
--- a/test/Discord.Net.Tests/Tests.Channels.cs
+++ b/test/Discord.Net.Tests/Tests.Channels.cs
@@ -16,17 +16,28 @@ internal static async Task Migration_CreateTextChannels(DiscordRestClient client
             var text4 = await guild.CreateTextChannelAsync("text4");
             var text5 = await guild.CreateTextChannelAsync("text5");
 
+            // create a channel category
+            var cat1 = await guild.CreateCategoryChannelAsync("cat1");
+
+            if (text1 == null)
+            {
+                // the guild did not have a default channel, so make a new one
+                text1 = await guild.CreateTextChannelAsync("default");
+            }
+
             //Modify #general
             await text1.ModifyAsync(x =>
             {
                 x.Name = "text1";
                 x.Position = 1;
                 x.Topic = "Topic1";
+                x.CategoryId = cat1.Id;
             });
 
             await text2.ModifyAsync(x =>
             {
                 x.Position = 2;
+                x.CategoryId = cat1.Id;
             });
             await text3.ModifyAsync(x =>
             {
@@ -90,10 +101,13 @@ internal static async Task Migration_CreateVoiceChannels(DiscordRestClient clien
             var voice2 = await guild.CreateVoiceChannelAsync("voice2");
             var voice3 = await guild.CreateVoiceChannelAsync("voice3");
 
+            var cat2 = await guild.CreateCategoryChannelAsync("cat2");
+
             await voice1.ModifyAsync(x =>
             {
                 x.Bitrate = 96000;
                 x.Position = 1;
+                x.CategoryId = cat2.Id;
             });
             await voice2.ModifyAsync(x =>
             {
@@ -104,6 +118,7 @@ internal static async Task Migration_CreateVoiceChannels(DiscordRestClient clien
                 x.Bitrate = 8000;
                 x.Position = 1;
                 x.UserLimit = 16;
+                x.CategoryId = cat2.Id;
             });
 
             CheckVoiceChannels(voice1, voice2, voice3);
@@ -143,49 +158,61 @@ private static void CheckVoiceChannels(params RestVoiceChannel[] voiceChannels)
         }
 
         [Fact]
-        public Task TestChannelCategories()
+        public async Task TestChannelCategories()
         {
-            CheckChannelCategories(_client, _guild);
+            // (await _guild.GetVoiceChannelsAsync()).ToArray()
+            var channels = await _guild.GetCategoryChannelsAsync();
 
-            return Task.CompletedTask;
+            await CheckChannelCategories(channels.ToArray(), (await _guild.GetChannelsAsync()).ToArray());
         }
 
-        private async static void CheckChannelCategories(DiscordRestClient client, RestGuild guild)
+        private async Task CheckChannelCategories(RestCategoryChannel[] categories, RestGuildChannel[] allChannels)
         {
-            // create some channel categories
-            var cat1 = await guild.CreateCategoryChannelAsync("Cat1");
-            var cat2 = await guild.CreateCategoryChannelAsync("Cat2");
+            // 2 categories
+            Assert.Equal(categories.Length, 2);
 
-            var text1 = await guild.CreateTextChannelAsync("nestedText1");
-            var voice1 = await guild.CreateVoiceChannelAsync("nestedVoice1");
-            // set the text channel parent to Cat 1
-            await text1.ModifyAsync(x =>
-            {
-                x.CategoryId = cat1.Id;
-            });
+            var cat1 = categories.Where(x => x.Name == "cat1").FirstOrDefault();
+            var cat2 = categories.Where(x => x.Name == "cat2").FirstOrDefault();
 
-            await voice1.ModifyAsync(x =>
-            {
-                x.CategoryId = cat2.Id;
-            });
+            Assert.NotNull(cat1);
+            Assert.NotNull(cat2);
 
-            // these shouldn't throw because they are not channel categories
+            // get text1, text2, ensure they have category id == cat1
+            var text1 = allChannels.Where(x => x.Name == "text1").FirstOrDefault() as RestTextChannel;
+            var text2 = allChannels.Where(x => x.Name == "text2").FirstOrDefault() as RestTextChannel;
 
-            // assert that CategoryId works for text channels
-            Assert.Equal(text1.CategoryId, cat1.Id);
-            Assert.True(text1 is INestedChannel);
-            Assert.Equal((await (text1 as INestedChannel).GetCategoryAsync()).Id, cat1.Id);
-            Assert.Equal((await text1.GetCategoryAsync()).Id, cat1.Id);
+            Assert.NotNull(text1);
+            Assert.NotNull(text2);
+
+            // check that CategoryID and .GetCategoryAsync work correctly
+            // for both of the text channels
             Assert.Equal(text1.CategoryId, cat1.Id);
+            var text1Cat = await text1.GetCategoryAsync();
+            Assert.Equal(text1Cat.Id, cat1.Id);
+            Assert.Equal(text1Cat.Name, cat1.Name);
+
+            Assert.Equal(text2.CategoryId, cat1.Id);
+            var text2Cat = await text2.GetCategoryAsync();
+            Assert.Equal(text2Cat.Id, cat1.Id);
+            Assert.Equal(text2Cat.Name, cat1.Name);
+
+            // do the same for the voice channels
+            var voice1 = allChannels.Where(x => x.Name == "voice1").FirstOrDefault() as RestVoiceChannel;
+            var voice3 = allChannels.Where(x => x.Name == "voice3").FirstOrDefault() as RestVoiceChannel;
 
-            // and for voice channels
+            Assert.NotNull(voice1);
+            Assert.NotNull(voice3);
+            
             Assert.Equal(voice1.CategoryId, cat2.Id);
-            Assert.True(voice1 is INestedChannel);
-            Assert.Equal((await (voice1 as INestedChannel).GetCategoryAsync()).Id, cat2.Id);
-            Assert.Equal((await voice1.GetCategoryAsync()).Id, cat2.Id);
-            Assert.Equal(voice1.CategoryId, cat1.Id);
+            var voice1Cat = await voice1.GetCategoryAsync();
+            Assert.Equal(voice1Cat.Id, cat2.Id);
+            Assert.Equal(voice1Cat.Name, cat2.Name);
+
+            Assert.Equal(voice3.CategoryId, cat2.Id);
+            var voice3Cat = await voice3.GetCategoryAsync();
+            Assert.Equal(voice3Cat.Id, cat2.Id);
+            Assert.Equal(voice3Cat.Name, cat2.Name);
 
-            // incomplete test, could use more coverage of other methods
         }
     }
 }

From 3ed1148ec88c9808334406519d8bc9d8d13bab5c Mon Sep 17 00:00:00 2001
From: Chris Johnston <chris@thejohnstons.net>
Date: Thu, 29 Mar 2018 21:36:09 -0700
Subject: [PATCH 12/20] remove outdated todo

---
 src/Discord.Net.Rest/Entities/Channels/RestGuildChannel.cs | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/Discord.Net.Rest/Entities/Channels/RestGuildChannel.cs b/src/Discord.Net.Rest/Entities/Channels/RestGuildChannel.cs
index 8bddcff09e..7355e3673d 100644
--- a/src/Discord.Net.Rest/Entities/Channels/RestGuildChannel.cs
+++ b/src/Discord.Net.Rest/Entities/Channels/RestGuildChannel.cs
@@ -34,7 +34,6 @@ internal static RestGuildChannel Create(BaseDiscordClient discord, IGuild guild,
                 case ChannelType.Category:
                     return RestCategoryChannel.Create(discord, guild, model);
                 default:
-                    // TODO: Channel categories
                     return new RestGuildChannel(discord, guild, model.Id);
             }
         }

From bb51b660d662b95b8524a05aa035f2deca892356 Mon Sep 17 00:00:00 2001
From: Chris Johnston <chris@thejohnstons.net>
Date: Tue, 3 Apr 2018 21:45:35 -0700
Subject: [PATCH 13/20] Make IVoiceChannel implement INestedChannel

---
 src/Discord.Net.Core/Entities/Channels/IVoiceChannel.cs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/Discord.Net.Core/Entities/Channels/IVoiceChannel.cs b/src/Discord.Net.Core/Entities/Channels/IVoiceChannel.cs
index e2a2ad8ebf..3f9ff953b2 100644
--- a/src/Discord.Net.Core/Entities/Channels/IVoiceChannel.cs
+++ b/src/Discord.Net.Core/Entities/Channels/IVoiceChannel.cs
@@ -1,9 +1,9 @@
-using System;
+using System;
 using System.Threading.Tasks;
 
 namespace Discord
 {
-    public interface IVoiceChannel : IGuildChannel, IAudioChannel
+    public interface IVoiceChannel : IGuildChannel, IAudioChannel, INestedChannel
     {
         /// <summary> Gets the bitrate, in bits per second, clients in this voice channel are requested to use. </summary>
         int Bitrate { get; }
@@ -13,4 +13,4 @@ public interface IVoiceChannel : IGuildChannel, IAudioChannel
         /// <summary> Modifies this voice channel. </summary>
         Task ModifyAsync(Action<VoiceChannelProperties> func, RequestOptions options = null);
     }
-}
\ No newline at end of file
+}

From f6f8576ccdbf105d8378bb10cd4000dec966084f Mon Sep 17 00:00:00 2001
From: Chris Johnston <chris@thejohnstons.net>
Date: Tue, 3 Apr 2018 21:47:10 -0700
Subject: [PATCH 14/20] remove redundant interface implementation

---
 src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs       | 2 +-
 src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs      | 2 +-
 .../Entities/Channels/SocketTextChannel.cs                      | 2 +-
 .../Entities/Channels/SocketVoiceChannel.cs                     | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs b/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs
index d597efa9aa..a9d07ae21b 100644
--- a/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs
+++ b/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs
@@ -9,7 +9,7 @@
 namespace Discord.Rest
 {
     [DebuggerDisplay(@"{DebuggerDisplay,nq}")]
-    public class RestTextChannel : RestGuildChannel, IRestMessageChannel, ITextChannel, INestedChannel
+    public class RestTextChannel : RestGuildChannel, IRestMessageChannel, ITextChannel
     {
         public string Topic { get; private set; }
         public ulong? CategoryId { get; private set; }
diff --git a/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs b/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs
index 870876ee00..a21c504450 100644
--- a/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs
+++ b/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs
@@ -9,7 +9,7 @@
 namespace Discord.Rest
 {
     [DebuggerDisplay(@"{DebuggerDisplay,nq}")]
-    public class RestVoiceChannel : RestGuildChannel, IVoiceChannel, IRestAudioChannel, INestedChannel
+    public class RestVoiceChannel : RestGuildChannel, IVoiceChannel, IRestAudioChannel
     {
         public int Bitrate { get; private set; }
         public int? UserLimit { get; private set; }
diff --git a/src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs b/src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs
index 54d8e53ee4..bf20fe863a 100644
--- a/src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs
+++ b/src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs
@@ -11,7 +11,7 @@
 namespace Discord.WebSocket
 {
     [DebuggerDisplay(@"{DebuggerDisplay,nq}")]
-    public class SocketTextChannel : SocketGuildChannel, ITextChannel, ISocketMessageChannel, INestedChannel
+    public class SocketTextChannel : SocketGuildChannel, ITextChannel, ISocketMessageChannel
     {
         private readonly MessageCache _messages;
 
diff --git a/src/Discord.Net.WebSocket/Entities/Channels/SocketVoiceChannel.cs b/src/Discord.Net.WebSocket/Entities/Channels/SocketVoiceChannel.cs
index 45d68bd852..50f61d135f 100644
--- a/src/Discord.Net.WebSocket/Entities/Channels/SocketVoiceChannel.cs
+++ b/src/Discord.Net.WebSocket/Entities/Channels/SocketVoiceChannel.cs
@@ -11,7 +11,7 @@
 namespace Discord.WebSocket
 {
     [DebuggerDisplay(@"{DebuggerDisplay,nq}")]
-    public class SocketVoiceChannel : SocketGuildChannel, IVoiceChannel, ISocketAudioChannel, INestedChannel
+    public class SocketVoiceChannel : SocketGuildChannel, IVoiceChannel, ISocketAudioChannel
     {
         public int Bitrate { get; private set; }
         public int? UserLimit { get; private set; }

From 252932c6329a2b01f77fd70e998e26e94c0b493d Mon Sep 17 00:00:00 2001
From: Chris Johnston <chris@thejohnstons.net>
Date: Tue, 3 Apr 2018 21:58:24 -0700
Subject: [PATCH 15/20] Add c#7 feature from feedback

---
 .../Entities/Channels/SocketCategoryChannel.cs                  | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs b/src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs
index 7b6619be6b..74ca02dba4 100644
--- a/src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs
+++ b/src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs
@@ -20,7 +20,7 @@ public override IReadOnlyCollection<SocketGuildUser> Users
                ChannelPermission.ViewChannel)).ToImmutableArray();
 
         public IReadOnlyCollection<SocketGuildChannel> Channels
-            => Guild.Channels.Where(x => x is INestedChannel && (x as INestedChannel).CategoryId == Id).ToImmutableArray();
+            => Guild.Channels.Where(x => x is INestedChannel nestedChannel && nestedChannel.CategoryId == Id).ToImmutableArray();
 
         internal SocketCategoryChannel(DiscordSocketClient discord, ulong id, SocketGuild guild)
             : base(discord, id, guild)

From e9ef02e8f46824d04d97fdce760b9a65bded9211 Mon Sep 17 00:00:00 2001
From: Chris Johnston <chris@thejohnstons.net>
Date: Tue, 3 Apr 2018 23:56:53 -0700
Subject: [PATCH 16/20] Remove redundant GetCategoryAsync methods from socket
 entities

---
 .../Entities/Channels/SocketTextChannel.cs                    | 4 ----
 .../Entities/Channels/SocketVoiceChannel.cs                   | 3 ---
 2 files changed, 7 deletions(-)

diff --git a/src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs b/src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs
index bf20fe863a..8a9398e274 100644
--- a/src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs
+++ b/src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs
@@ -124,10 +124,6 @@ public Task<RestWebhook> GetWebhookAsync(ulong id, RequestOptions options = null
         public Task<IReadOnlyCollection<RestWebhook>> GetWebhooksAsync(RequestOptions options = null)
             => ChannelHelper.GetWebhooksAsync(this, Discord, options);
 
-        // Categories
-        public Task<ICategoryChannel> GetCategoryAsync(RequestOptions options = null)
-            => ChannelHelper.GetCategoryAsync(this, Discord, options);
-
         private string DebuggerDisplay => $"{Name} ({Id}, Text)";
         internal new SocketTextChannel Clone() => MemberwiseClone() as SocketTextChannel;
 
diff --git a/src/Discord.Net.WebSocket/Entities/Channels/SocketVoiceChannel.cs b/src/Discord.Net.WebSocket/Entities/Channels/SocketVoiceChannel.cs
index 50f61d135f..8029697fa0 100644
--- a/src/Discord.Net.WebSocket/Entities/Channels/SocketVoiceChannel.cs
+++ b/src/Discord.Net.WebSocket/Entities/Channels/SocketVoiceChannel.cs
@@ -56,9 +56,6 @@ public override SocketGuildUser GetUser(ulong id)
             return null;
         }
 
-        public Task<ICategoryChannel> GetCategoryAsync(RequestOptions options = null)
-            => ChannelHelper.GetCategoryAsync(this, Discord, options);
-
         private string DebuggerDisplay => $"{Name} ({Id}, Voice)";
         internal new SocketVoiceChannel Clone() => MemberwiseClone() as SocketVoiceChannel;
 

From bb6b879fb2dae7c2bc9a9614d0f017d82db66873 Mon Sep 17 00:00:00 2001
From: Chris Johnston <chris@thejohnstons.net>
Date: Tue, 3 Apr 2018 23:59:10 -0700
Subject: [PATCH 17/20] Added configureawait to async methods

---
 src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs b/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs
index a9d07ae21b..dbf4eb6884 100644
--- a/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs
+++ b/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs
@@ -92,11 +92,11 @@ public Task<ICategoryChannel> GetCategoryAsync(RequestOptions options = null)
 
         //ITextChannel
         async Task<IWebhook> ITextChannel.CreateWebhookAsync(string name, Stream avatar, RequestOptions options)
-            => await CreateWebhookAsync(name, avatar, options);
+            => await CreateWebhookAsync(name, avatar, options).ConfigureAwait(false);
         async Task<IWebhook> ITextChannel.GetWebhookAsync(ulong id, RequestOptions options)
-            => await GetWebhookAsync(id, options);
+            => await GetWebhookAsync(id, options).ConfigureAwait(false);
         async Task<IReadOnlyCollection<IWebhook>> ITextChannel.GetWebhooksAsync(RequestOptions options)
-            => await GetWebhooksAsync(options);
+            => await GetWebhooksAsync(options).ConfigureAwait(false);
 
         //IMessageChannel
         async Task<IMessage> IMessageChannel.GetMessageAsync(ulong id, CacheMode mode, RequestOptions options)

From cd37d63be41069aa84868107d5604ce17b74ddd1 Mon Sep 17 00:00:00 2001
From: Chris Johnston <chris@thejohnstons.net>
Date: Wed, 4 Apr 2018 00:08:10 -0700
Subject: [PATCH 18/20] change signature of interface GetCategoryAsync

---
 src/Discord.Net.Core/Entities/Channels/INestedChannel.cs      | 2 +-
 src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs     | 4 ++--
 src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs    | 4 ++--
 .../Entities/Channels/SocketTextChannel.cs                    | 2 +-
 .../Entities/Channels/SocketVoiceChannel.cs                   | 2 +-
 5 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/Discord.Net.Core/Entities/Channels/INestedChannel.cs b/src/Discord.Net.Core/Entities/Channels/INestedChannel.cs
index 4082bfbb2b..c8d2bcaafb 100644
--- a/src/Discord.Net.Core/Entities/Channels/INestedChannel.cs
+++ b/src/Discord.Net.Core/Entities/Channels/INestedChannel.cs
@@ -11,6 +11,6 @@ public interface INestedChannel : IGuildChannel
         /// <summary> Gets the parentid (category) of this channel in the guild's channel list. </summary>
         ulong? CategoryId { get; }
         /// <summary> Gets the parent channel (category) of this channel, if it is set. If unset, returns null.</summary>
-        Task<ICategoryChannel> GetCategoryAsync();
+        Task<ICategoryChannel> GetCategoryAsync(CacheMode mode = CacheMode.AllowDownload, RequestOptions options = null);
     }
 }
diff --git a/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs b/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs
index dbf4eb6884..61b587cde2 100644
--- a/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs
+++ b/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs
@@ -175,10 +175,10 @@ IAsyncEnumerable<IReadOnlyCollection<IUser>> IChannel.GetUsersAsync(CacheMode mo
         }
 
         // INestedChannel
-        async Task<ICategoryChannel> INestedChannel.GetCategoryAsync()
+        async Task<ICategoryChannel> INestedChannel.GetCategoryAsync(CacheMode mode, RequestOptions options)
         {
             if (CategoryId.HasValue)
-                return (await Guild.GetChannelAsync(CategoryId.Value).ConfigureAwait(false)) as ICategoryChannel;
+                return (await Guild.GetChannelAsync(CategoryId.Value, mode, options).ConfigureAwait(false)) as ICategoryChannel;
             return null;
         }
     }
diff --git a/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs b/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs
index a21c504450..342651e872 100644
--- a/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs
+++ b/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs
@@ -54,10 +54,10 @@ IAsyncEnumerable<IReadOnlyCollection<IGuildUser>> IGuildChannel.GetUsersAsync(Ca
             => AsyncEnumerable.Empty<IReadOnlyCollection<IGuildUser>>();
 
         // INestedChannel
-        async Task<ICategoryChannel> INestedChannel.GetCategoryAsync()
+        async Task<ICategoryChannel> INestedChannel.GetCategoryAsync(CacheMode mode, RequestOptions options)
         {
             if (CategoryId.HasValue)
-                return (await Guild.GetChannelAsync(CategoryId.Value).ConfigureAwait(false)) as ICategoryChannel;
+                return (await Guild.GetChannelAsync(CategoryId.Value, mode, options).ConfigureAwait(false)) as ICategoryChannel;
             return null;
         }
     }
diff --git a/src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs b/src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs
index 8a9398e274..0b01f34c38 100644
--- a/src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs
+++ b/src/Discord.Net.WebSocket/Entities/Channels/SocketTextChannel.cs
@@ -169,7 +169,7 @@ IDisposable IMessageChannel.EnterTypingState(RequestOptions options)
             => EnterTypingState(options);
 
         // INestedChannel
-        Task<ICategoryChannel> INestedChannel.GetCategoryAsync()
+        Task<ICategoryChannel> INestedChannel.GetCategoryAsync(CacheMode mode, RequestOptions options)
             => Task.FromResult(Category);
     }
 }
diff --git a/src/Discord.Net.WebSocket/Entities/Channels/SocketVoiceChannel.cs b/src/Discord.Net.WebSocket/Entities/Channels/SocketVoiceChannel.cs
index 8029697fa0..349621fac3 100644
--- a/src/Discord.Net.WebSocket/Entities/Channels/SocketVoiceChannel.cs
+++ b/src/Discord.Net.WebSocket/Entities/Channels/SocketVoiceChannel.cs
@@ -66,7 +66,7 @@ IAsyncEnumerable<IReadOnlyCollection<IGuildUser>> IGuildChannel.GetUsersAsync(Ca
             => ImmutableArray.Create<IReadOnlyCollection<IGuildUser>>(Users).ToAsyncEnumerable();
 
         // INestedChannel
-        Task<ICategoryChannel> INestedChannel.GetCategoryAsync()
+        Task<ICategoryChannel> INestedChannel.GetCategoryAsync(CacheMode mode, RequestOptions options)
             => Task.FromResult(Category);
     }
 }

From 36f49e1d25d17434331762ac27ed6833c56022f7 Mon Sep 17 00:00:00 2001
From: Chris Johnston <chris@thejohnstons.net>
Date: Wed, 4 Apr 2018 02:38:29 -0700
Subject: [PATCH 19/20] Add check for cachemode in rest channel GetCategory

---
 src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs  | 2 +-
 src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs b/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs
index 61b587cde2..9b72fb3661 100644
--- a/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs
+++ b/src/Discord.Net.Rest/Entities/Channels/RestTextChannel.cs
@@ -177,7 +177,7 @@ IAsyncEnumerable<IReadOnlyCollection<IUser>> IChannel.GetUsersAsync(CacheMode mo
         // INestedChannel
         async Task<ICategoryChannel> INestedChannel.GetCategoryAsync(CacheMode mode, RequestOptions options)
         {
-            if (CategoryId.HasValue)
+            if (CategoryId.HasValue && mode == CacheMode.AllowDownload)
                 return (await Guild.GetChannelAsync(CategoryId.Value, mode, options).ConfigureAwait(false)) as ICategoryChannel;
             return null;
         }
diff --git a/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs b/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs
index 342651e872..a2bead45fe 100644
--- a/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs
+++ b/src/Discord.Net.Rest/Entities/Channels/RestVoiceChannel.cs
@@ -56,7 +56,7 @@ IAsyncEnumerable<IReadOnlyCollection<IGuildUser>> IGuildChannel.GetUsersAsync(Ca
         // INestedChannel
         async Task<ICategoryChannel> INestedChannel.GetCategoryAsync(CacheMode mode, RequestOptions options)
         {
-            if (CategoryId.HasValue)
+            if (CategoryId.HasValue && mode == CacheMode.AllowDownload)
                 return (await Guild.GetChannelAsync(CategoryId.Value, mode, options).ConfigureAwait(false)) as ICategoryChannel;
             return null;
         }

From 3cf417a112b226d8350a763ca2fabfa8d4baffb2 Mon Sep 17 00:00:00 2001
From: Chris Johnston <chris@thejohnstons.net>
Date: Thu, 5 Apr 2018 14:43:42 -0700
Subject: [PATCH 20/20] remove redundant IGuildChannel interface from
 ITextChannel and IVoiceChannel

---
 src/Discord.Net.Core/Entities/Channels/ITextChannel.cs  | 2 +-
 src/Discord.Net.Core/Entities/Channels/IVoiceChannel.cs | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Discord.Net.Core/Entities/Channels/ITextChannel.cs b/src/Discord.Net.Core/Entities/Channels/ITextChannel.cs
index ae15ce2bae..2aa070b03d 100644
--- a/src/Discord.Net.Core/Entities/Channels/ITextChannel.cs
+++ b/src/Discord.Net.Core/Entities/Channels/ITextChannel.cs
@@ -5,7 +5,7 @@
 
 namespace Discord
 {
-    public interface ITextChannel : IMessageChannel, IMentionable, IGuildChannel, INestedChannel
+    public interface ITextChannel : IMessageChannel, IMentionable, INestedChannel
     {
         /// <summary> Checks if the channel is NSFW. </summary>
         bool IsNsfw { get; }
diff --git a/src/Discord.Net.Core/Entities/Channels/IVoiceChannel.cs b/src/Discord.Net.Core/Entities/Channels/IVoiceChannel.cs
index 3f9ff953b2..2e345bfda2 100644
--- a/src/Discord.Net.Core/Entities/Channels/IVoiceChannel.cs
+++ b/src/Discord.Net.Core/Entities/Channels/IVoiceChannel.cs
@@ -3,7 +3,7 @@
 
 namespace Discord
 {
-    public interface IVoiceChannel : IGuildChannel, IAudioChannel, INestedChannel
+    public interface IVoiceChannel : INestedChannel, IAudioChannel
     {
         /// <summary> Gets the bitrate, in bits per second, clients in this voice channel are requested to use. </summary>
         int Bitrate { get; }