DiscordClient throws when registering command with some overloads

Summary

A NullReferenceException occurs when trying to register a command with some overloads with default values, but works fine if you make overloads explicit.

Details

Using .net core 2.1 with DSharpPlus & CommandsNext nightly 4.0.0-nightly-00564.

Stacktrace:

System.NullReferenceException: Object reference not set to an instance of an object.
   at DSharpPlus.DiscordClient.Dispose()
   at CompatBot.Program.Main(String[] args) in C:\\Develop\\discord-bot\\CompatBot\\Program.cs:line 262

Line 262 is the end of the using scope, it throws on registering the command inside said scope.

Example of a command overload:

class BadOverload
{
    [Command("c")]
    public async Task Crash(CommandContext ctx, int? year = null) => ;

    [Command("c")]
    public async Task Crash(CommandContext ctx, string name = null, int? year = null) => ;
}

Steps to reproduce

1. Have a command overload similar to example

2. Try to register it to the client

3. Observe exception

4. Change overloads to be explicit (4 instead of 2 with default value)

5. Observe no exceptions

Notes

Exception that is being thrown, is useless as it points to trying to dispose a null client for some reason, instead of pointing to the issue with overload resolving.

[WamWooWam]

Don’t do that, dispose the client when you’re application exits, or alternatively don’t at all, in doing so you’re disconnecting the client, probably before it actually connects in the first place

[WamWooWam]

Also are you using your discord client? Because you shouldn’t be doing that