[V3] Ban peers with hackban

[Liante-0216]

Command bugs

Command name

[p]hackban

What cog is this command from?

Mod

What were you expecting to happen?

When called by a mod on another mod, display error message: "I cannot let you do that. You are not higher than the user in the role hierarchy." and do nothing.

What actually happened?

Mod got banned, message displayed: "Done. The user will not be able to join this server."

How can we reproduce this issue?

1. Set a role with ban permissions and access to the Mod cog and hackban command.
2. Give the role to two members, it should be the highest role for both of them.
3. Have one of them execute [p]hackban <other's id>

[Kowlin]

Can confirm that this is a bug. Also as an additional bug, ban does not check if you can actually ban the user and it will error out if the bot doesn't have the permissions to ban.

Traceback

Exception in command 'hackban' Traceback (most recent call last): File "/usr/local/lib/python3.6/dist-packages/discord/ext/commands/core.py", line 61, in wrapped ret = await coro(*args, **kwargs) File "/usr/local/lib/python3.6/dist-packages/redbot/cogs/mod/mod.py", line 441, in hackban ban_list = await guild.bans() File "/usr/local/lib/python3.6/dist-packages/discord/guild.py", line 857, in bans data = await self._state.http.get_bans(self.id) File "/usr/local/lib/python3.6/dist-packages/discord/http.py", line 209, in request raise Forbidden(r, data) discord.errors.Forbidden: FORBIDDEN (status code: 403): Missing Permissions

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
File "/usr/local/lib/python3.6/dist-packages/discord/ext/commands/bot.py", line 898, in invoke
await ctx.command.invoke(ctx)
File "/usr/local/lib/python3.6/dist-packages/discord/ext/commands/core.py", line 550, in invoke
await injected(*ctx.args, **ctx.kwargs)
File "/usr/local/lib/python3.6/dist-packages/discord/ext/commands/core.py", line 70, in wrapped
raise CommandInvokeError(e) from e
discord.ext.commands.errors.CommandInvokeError: Command raised an exception: Forbidden: FORBIDDEN (status code: 403): Missing Permissions

[Tobotimus]

Thanks for this report. Resolved by #2128.