Fix inaccuracies with `AsyncIterator` typings

discord/iterators.py

@@ -26,7 +26,7 @@ from __future__ import annotations
 
 import asyncio
 import datetime
-from typing import TYPE_CHECKING, TypeVar, Optional, Any, Callable, Union, List, AsyncIterator, Coroutine
+from typing import Awaitable, TYPE_CHECKING, TypeVar, Optional, Any, Callable, Union, List, AsyncIterator
 
 from .errors import NoMoreItems
 from .utils import time_snowflake, maybe_coroutine
@@ -50,16 +50,18 @@ if TYPE_CHECKING:
 
 T = TypeVar('T')
 OT = TypeVar('OT')
-_Func = Callable[[T], Union[OT, Coroutine[Any, Any, OT]]]
-_Predicate = Callable[[T], Union[T, Coroutine[Any, Any, T]]]
+_Func = Callable[[T], Union[OT, Awaitable[OT]]]
 
 OLDEST_OBJECT = Object(id=0)
 
 class _AsyncIterator(AsyncIterator[T]):
     __slots__ = ()
 
-    def get(self, **attrs: Any) -> Optional[T]:
-        def predicate(elem):
+    async def next(self) -> T:
+        raise NotImplementedError
+
+    def get(self, **attrs: Any) -> Awaitable[Optional[T]]:
+        def predicate(elem: T):
             for attr, val in attrs.items():
                 nested = attr.split('__')
                 obj = elem
@@ -72,7 +74,7 @@ class _AsyncIterator(AsyncIterator[T]):
 
         return self.find(predicate)
 
-    async def find(self, predicate: _Predicate[T]) -> Optional[T]:
+    async def find(self, predicate: _Func[T, bool]) -> Optional[T]:
         while True:
             try:
                 elem = await self.next()
@@ -91,7 +93,7 @@ class _AsyncIterator(AsyncIterator[T]):
     def map(self, func: _Func[T, OT]) -> _MappedAsyncIterator[OT]:
         return _MappedAsyncIterator(self, func)
 
-    def filter(self, predicate: _Predicate[T]) -> _FilteredAsyncIterator[T]:
+    def filter(self, predicate: _Func[T, bool]) -> _FilteredAsyncIterator[T]:
         return _FilteredAsyncIterator(self, predicate)
 
     async def flatten(self) -> List[T]:
@@ -106,13 +108,13 @@ class _AsyncIterator(AsyncIterator[T]):
 def _identity(x):
     return x
 
-class _ChunkedAsyncIterator(_AsyncIterator[T]):
+class _ChunkedAsyncIterator(_AsyncIterator[List[T]]):
     def __init__(self, iterator, max_size):
         self.iterator = iterator
         self.max_size = max_size
 
-    async def next(self) -> T:
-        ret = []
+    async def next(self) -> List[T]:
+        ret: List[T] = []
         n = 0
         while n < self.max_size:
             try:
@@ -168,7 +170,7 @@ class ReactionIterator(_AsyncIterator[Union['User', 'Member']]):
         self.channel_id = message.channel.id
         self.users = asyncio.Queue()
 
-    async def next(self) -> T:
+    async def next(self) -> Union[User, Member]:
         if self.users.empty():
             await self.fill_users()
 
@@ -289,7 +291,7 @@ class HistoryIterator(_AsyncIterator['Message']):
                 if (self.after and self.after != OLDEST_OBJECT):
                     self._filter = lambda m: int(m['id']) > self.after.id
 
-    async def next(self) -> T:
+    async def next(self) -> Message:
         if self.messages.empty():
             await self.fill_messages()
 
@@ -422,7 +424,7 @@ class AuditLogIterator(_AsyncIterator['AuditLogEntry']):
             self.after = Object(id=int(entries[0]['id']))
         return data.get('users', []), entries
 
-    async def next(self) -> T:
+    async def next(self) -> AuditLogEntry:
         if self.entries.empty():
             await self._fill()
 
@@ -519,7 +521,7 @@ class GuildIterator(_AsyncIterator['Guild']):
         else:
             self._retrieve_guilds = self._retrieve_guilds_before_strategy
 
-    async def next(self) -> T:
+    async def next(self) -> Guild:
         if self.guilds.empty():
             await self.fill_guilds()
 
@@ -591,7 +593,7 @@ class MemberIterator(_AsyncIterator['Member']):
         self.get_members = self.state.http.get_members
         self.members = asyncio.Queue()
 
-    async def next(self) -> T:
+    async def next(self) -> Member:
         if self.members.empty():
             await self.fill_members()