Parameter ctx isnt detected even if its being passed in for certain subcommands

[aryaniyaps]

Summary

So I was making a subcommand inside a cog. But then, when I ran my code after creating it, I got this error:

    raise MissingRequiredArgument(param)
discord.ext.commands.errors.MissingRequiredArgument: ctx is a required argument that is missing.

I think that this is a bug with dpy, not sure.

Reproduction Steps

So here's my code.

class Configuration(commands.Cog):
    def __init__(self, client):
        self.client = client
@commands.group(invoke_without_command=True)
    async def plugin(self, ctx, invalid_module=None):

 @plugin.command()
    @commands.guild_only()
    async def list(self, ctx, module_name=None):

I made my subcommand inside the cog like this [I think that sructure matters]
So if u make a subcommand like this and try to run u'll get the above mentioned error

Expected Results

I expected the command to work fine, because similar subcommands which were created earlier worked fine.

Actual Results

I got this error.
Here's the full traceback:

Ignoring exception in command plugin list:
Traceback (most recent call last):
  File "C:\Users\Iyappan\AppData\Local\Programs\Python\Python36\lib\site-packages\discord\ext\commands\bot.py", line 903, in invoke
    await ctx.command.invoke(ctx)
  File "C:\Users\Iyappan\AppData\Local\Programs\Python\Python36\lib\site-packages\discord\ext\commands\core.py", line 1329, in invoke
    await ctx.invoked_subcommand.invoke(ctx)
  File "C:\Users\Iyappan\AppData\Local\Programs\Python\Python36\lib\site-packages\discord\ext\commands\core.py", line 851, in invoke
    await self.prepare(ctx)
  File "C:\Users\Iyappan\AppData\Local\Programs\Python\Python36\lib\site-packages\discord\ext\commands\core.py", line 786, in prepare
    await self._parse_arguments(ctx)
  File "C:\Users\Iyappan\AppData\Local\Programs\Python\Python36\lib\site-packages\discord\ext\commands\core.py", line 697, in _parse_arguments
    transformed = await self.transform(ctx, param)
  File "C:\Users\Iyappan\AppData\Local\Programs\Python\Python36\lib\site-packages\discord\ext\commands\core.py", line 542, in transform
    raise MissingRequiredArgument(param)
discord.ext.commands.errors.MissingRequiredArgument: ctx is a required argument that is missing.

Intents

Dont think this applies, anyways I have members and presence intents enabled in my dev portal

Checklist

• [> ] I have hopefully searched the open issues for duplicates.
• [ >] I have shown the entire traceback, if possible.
• [> ] I have removed my token from display, if visible.
• [> ] I have provided the intents that my bot is using.

System Information

- Python v3.6.5-final
- discord.py v1.5.0-final
- aiohttp v3.6.2
- system info: Windows 10 10.0.17763

[Rapptz]

This happens when you have multiple functions with the same name, for example:

class Example(commands.Cog):
    @commands.command()
     async def bar(self, ctx):
         pass

    @commands.group()
     async def foo(self, ctx):
         pass

    @foo.command()
     async def bar(self, ctx):
         pass