c#7 pattern matching

src/Discord.Net.Commands/Attributes/Preconditions/RequireBotPermissionAttribute.cs

@@ -57,10 +57,8 @@ namespace Discord.Commands
 
             if (ChannelPermission.HasValue)
             {
-                var guildChannel = context.Channel as IGuildChannel;
-
                 ChannelPermissions perms;
-                if (guildChannel != null)
+                if (context.Channel is IGuildChannel guildChannel)
                     perms = guildUser.GetPermissions(guildChannel);
                 else
                     perms = ChannelPermissions.All(context.Channel);

src/Discord.Net.Commands/Attributes/Preconditions/RequireUserPermissionAttribute.cs

@@ -56,10 +56,8 @@ namespace Discord.Commands
 
             if (ChannelPermission.HasValue)
             {
-                var guildChannel = context.Channel as IGuildChannel;
-
                 ChannelPermissions perms;
-                if (guildChannel != null)
+                if (context.Channel is IGuildChannel guildChannel)
                     perms = guildUser.GetPermissions(guildChannel);
                 else
                     perms = ChannelPermissions.All(context.Channel);