Removes the caching behavior of Member.roles

- fixes 4087
- This intentionally uses some internals in both Member.roles and
Member.top_role to retain as much performance as possible while
removing the cache

discord/member.py

@@ -161,7 +161,7 @@ class Member(discord.abc.Messageable, _BaseUser):
         Nitro boost on the guild, if available. This could be ``None``.
     """
 
-    __slots__ = ('_roles', '_cs_roles', 'joined_at', 'premium_since', '_client_status',
+    __slots__ = ('_roles', 'joined_at', 'premium_since', '_client_status',
                  'activities', 'guild', 'nick', '_user', '_state')
 
     def __init__(self, *, data, guild, state):
@@ -234,11 +234,6 @@ class Member(discord.abc.Messageable, _BaseUser):
         self.activities = member.activities
         self._state = member._state
 
-        try:
-            del self._cs_roles
-        except AttributeError:
-            pass
-
         # Reference will not be copied unless necessary by PRESENCE_UPDATE
         # See below
         self._user = member._user
@@ -250,10 +245,6 @@ class Member(discord.abc.Messageable, _BaseUser):
 
     def _update_roles(self, data):
         self._roles = utils.SnowflakeList(map(int, data['roles']))
-        try:
-            del self._cs_roles
-        except AttributeError:
-            pass
 
     def _update(self, data):
         # the nickname change is optional,
@@ -344,7 +335,7 @@ class Member(discord.abc.Messageable, _BaseUser):
         """
         return self.colour
 
-    @utils.cached_slot_property('_cs_roles')
+    @property
     def roles(self):
         """List[:class:`Role`]: A :class:`list` of :class:`Role` that the member belongs to. Note
         that the first element of this list is always the default '@everyone'
@@ -434,7 +425,11 @@ class Member(discord.abc.Messageable, _BaseUser):
         This is useful for figuring where a member stands in the role
         hierarchy chain.
         """
-        return self.roles[-1]
+        guild = self.guild
+        if len(self._roles) == 0:
+            return guild.default_role
+        
+        return max(guild.get_role(rid) or guild.default_role for rid in self._roles)
 
     @property
     def guild_permissions(self):