Fix role comparison

src/Discord.Net.Core/Extensions/RoleExtensions.cs

@@ -0,0 +1,19 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Discord
+{
+  public static class RoleExtensions
+  {
+    internal static int Compare(this IRole r1, IRole r2) {
+      if(r2 == null)
+        return 1;
+      var result = r1.Position.CompareTo(r2.Position);
+      // As per Discord's documentation, a tie is broken by ID
+      if(result != 0)
+        return result;
+      return r1.Id.CompareTo(r2.Id);
+    }
+  }
+}