[commands] Add Context.current_parameter

discord/ext/commands/context.py

@@ -53,6 +53,11 @@ class Context(discord.abc.Messageable):
         A dictionary of transformed arguments that were passed into the command.
         Similar to :attr:`args`\, if this is accessed in the
         :func:`on_command_error` event then this dict could be incomplete.
+    current_parameter: Optional[:class:`inspect.Parameter`]
+        The parameter that is currently being inspected and converted.
+        This is only of use for within converters.
+
+        .. versionadded:: 2.0
     prefix: :class:`str`
         The prefix that was used to invoke the command.
     command: :class:`Command`
@@ -94,6 +99,7 @@ class Context(discord.abc.Messageable):
         self.invoked_subcommand = attrs.pop('invoked_subcommand', None)
         self.subcommand_passed = attrs.pop('subcommand_passed', None)
         self.command_failed = attrs.pop('command_failed', False)
+        self.current_parameter = attrs.pop('current_parameter', None)
         self._state = self.message._state
 
     async def invoke(self, command, /, *args, **kwargs):

discord/ext/commands/core.py

@@ -819,6 +819,7 @@ class Command(_BaseCommand):
             raise discord.ClientException(f'Callback for {self.name} command is missing "ctx" parameter.')
 
         for name, param in iterator:
+            ctx.current_parameter = param
             if param.kind in (param.POSITIONAL_OR_KEYWORD, param.POSITIONAL_ONLY):
                 transformed = await self.transform(ctx, param)
                 args.append(transformed)