Fix return annotations of several methods that return self at runtime

stdlib/asyncio/streams.pyi

@@ -1,5 +1,5 @@
 import sys
-from _typeshed import StrPath
+from _typeshed import Self, StrPath
 from typing import Any, AsyncIterator, Awaitable, Callable, Iterable, Optional
 
 from . import events, protocols, transports
@@ -117,7 +117,7 @@ class StreamWriter:
     def get_extra_info(self, name: str, default: Any = ...) -> Any: ...
     async def drain(self) -> None: ...
 
-class StreamReader:
+class StreamReader(AsyncIterator[bytes]):
     def __init__(self, limit: int = ..., loop: events.AbstractEventLoop | None = ...) -> None: ...
     def exception(self) -> Exception: ...
     def set_exception(self, exc: Exception) -> None: ...
@@ -129,5 +129,5 @@ class StreamReader:
     async def readuntil(self, separator: bytes = ...) -> bytes: ...
     async def read(self, n: int = ...) -> bytes: ...
     async def readexactly(self, n: int) -> bytes: ...
-    def __aiter__(self) -> AsyncIterator[bytes]: ...
+    def __aiter__(self: Self) -> Self: ...
     async def __anext__(self) -> bytes: ...

stdlib/codecs.pyi

@@ -86,7 +86,7 @@ class CodecInfo(tuple[_Encoder, _Decoder, _StreamReader, _StreamWriter]):
     def incrementaldecoder(self) -> _IncrementalDecoder: ...
     name: str
     def __new__(
-        cls,
+        cls: type[Self],
         encode: _Encoder,
         decode: _Decoder,
         streamreader: _StreamReader | None = ...,
@@ -96,7 +96,7 @@ class CodecInfo(tuple[_Encoder, _Decoder, _StreamReader, _StreamWriter]):
         name: str | None = ...,
         *,
         _is_text_encoding: bool | None = ...,
-    ) -> CodecInfo: ...
+    ) -> Self: ...
 
 def getencoder(encoding: str) -> _Encoder: ...
 def getdecoder(encoding: str) -> _Decoder: ...
@@ -189,7 +189,7 @@ class StreamWriter(Codec):
     def __exit__(self, typ: type[BaseException] | None, exc: BaseException | None, tb: types.TracebackType | None) -> None: ...
     def __getattr__(self, name: str, getattr: Callable[[str], Any] = ...) -> Any: ...
 
-class StreamReader(Codec):
+class StreamReader(Codec, Iterator[str]):
     errors: str
     def __init__(self, stream: IO[bytes], errors: str = ...) -> None: ...
     def read(self, size: int = ..., chars: int = ..., firstline: bool = ...) -> str: ...
@@ -198,7 +198,8 @@ class StreamReader(Codec):
     def reset(self) -> None: ...
     def __enter__(self: Self) -> Self: ...
     def __exit__(self, typ: type[BaseException] | None, exc: BaseException | None, tb: types.TracebackType | None) -> None: ...
-    def __iter__(self) -> Iterator[str]: ...
+    def __iter__(self: Self) -> Self: ...
+    def __next__(self) -> str: ...
     def __getattr__(self, name: str, getattr: Callable[[str], Any] = ...) -> Any: ...
 
 # Doesn't actually inherit from TextIO, but wraps a BinaryIO to provide text reading and writing

stdlib/csv.pyi

@@ -17,6 +17,7 @@ from _csv import (
     unregister_dialect as unregister_dialect,
     writer as writer,
 )
+from _typeshed import Self
 from collections.abc import Collection, Iterable, Iterator, Mapping, Sequence
 from typing import Any, Generic, TypeVar, overload
 
@@ -75,7 +76,7 @@ class DictReader(Generic[_T], Iterator[_DictReadMapping[_T, str]]):
         *args: Any,
         **kwds: Any,
     ) -> None: ...
-    def __iter__(self) -> DictReader[_T]: ...
+    def __iter__(self: Self) -> Self: ...
     def __next__(self) -> _DictReadMapping[_T, str]: ...
 
 class DictWriter(Generic[_T]):

stdlib/fileinput.pyi

@@ -46,7 +46,7 @@ def fileno() -> int: ...
 def isfirstline() -> bool: ...
 def isstdin() -> bool: ...
 
-class FileInput(Iterable[AnyStr], Generic[AnyStr]):
+class FileInput(Iterator[AnyStr], Generic[AnyStr]):
     if sys.version_info >= (3, 10):
         def __init__(
             self,
@@ -83,7 +83,7 @@ class FileInput(Iterable[AnyStr], Generic[AnyStr]):
     def close(self) -> None: ...
     def __enter__(self: Self) -> Self: ...
     def __exit__(self, type: Any, value: Any, traceback: Any) -> None: ...
-    def __iter__(self) -> Iterator[AnyStr]: ...
+    def __iter__(self: Self) -> Self: ...
     def __next__(self) -> AnyStr: ...
     if sys.version_info < (3, 11):
         def __getitem__(self, i: int) -> AnyStr: ...

stdlib/pdb.pyi

@@ -1,5 +1,6 @@
 import signal
 import sys
+from _typeshed import Self
 from bdb import Bdb
 from cmd import Cmd
 from inspect import _SourceObjectType
@@ -173,4 +174,4 @@ def getsourcelines(obj: _SourceObjectType) -> tuple[list[str], int]: ...
 def lasti2lineno(code: CodeType, lasti: int) -> int: ...
 
 class _rstr(str):
-    def __repr__(self) -> _rstr: ...
+    def __repr__(self: Self) -> Self: ...

stdlib/sre_constants.pyi

@@ -1,4 +1,5 @@
 import sys
+from _typeshed import Self
 from typing import Any
 
 MAXGROUPS: int
@@ -15,7 +16,7 @@ class error(Exception):
 
 class _NamedIntConstant(int):
     name: Any
-    def __new__(cls, value: int, name: str) -> _NamedIntConstant: ...
+    def __new__(cls: type[Self], value: int, name: str) -> Self: ...
 
 MAXREPEAT: _NamedIntConstant
 OPCODES: list[_NamedIntConstant]

stdlib/ssl.pyi

@@ -396,7 +396,7 @@ class SSLContext:
     if sys.version_info >= (3, 8):
         keylog_filename: str
         post_handshake_auth: bool
-    def __new__(cls, protocol: int = ..., *args: Any, **kwargs: Any) -> SSLContext: ...
+    def __new__(cls: type[Self], protocol: int = ..., *args: Any, **kwargs: Any) -> Self: ...
     def __init__(self, protocol: int = ...) -> None: ...
     def cert_store_stats(self) -> dict[str, int]: ...
     def load_cert_chain(

stdlib/weakref.pyi

@@ -25,7 +25,7 @@ _P = ParamSpec("_P")
 ProxyTypes: tuple[type[Any], ...]
 
 class WeakMethod(ref[_CallableT], Generic[_CallableT]):
-    def __new__(cls, meth: _CallableT, callback: Callable[[_CallableT], object] | None = ...) -> WeakMethod[_CallableT]: ...
+    def __new__(cls: type[Self], meth: _CallableT, callback: Callable[[_CallableT], object] | None = ...) -> Self: ...
     def __call__(self) -> _CallableT | None: ...
 
 class WeakValueDictionary(MutableMapping[_KT, _VT]):
@@ -67,7 +67,7 @@ class WeakValueDictionary(MutableMapping[_KT, _VT]):
 class KeyedRef(ref[_T], Generic[_KT, _T]):
     key: _KT
     # This __new__ method uses a non-standard name for the "cls" parameter
-    def __new__(type, ob: _T, callback: Callable[[_T], Any], key: _KT) -> KeyedRef[_KT, _T]: ...  # type: ignore
+    def __new__(type: type[Self], ob: _T, callback: Callable[[_T], Any], key: _KT) -> Self: ...  # type: ignore
     def __init__(self, ob: _T, callback: Callable[[_T], Any], key: _KT) -> None: ...
 
 class WeakKeyDictionary(MutableMapping[_KT, _VT]):