python · JelleZijlstra · Jun 14, 2022 · Jun 14, 2022 · Jun 14, 2022 · Jun 14, 2022
diff --git a/stdlib/ctypes/__init__.pyi b/stdlib/ctypes/__init__.pyi
@@ -164,7 +164,7 @@ def POINTER(type: type[_CT]) -> type[pointer[_CT]]: ...
 class pointer(Generic[_CT], _PointerLike, _CData):
     _type_: type[_CT]
     contents: _CT
-    def __init__(self, arg: _CT = ...) -> None: ...
+    def __init__(self, arg: _CT) -> None: ...
     @overload
     def __getitem__(self, __i: int) -> _CT: ...
     @overload

diff --git a/stdlib/difflib.pyi b/stdlib/difflib.pyi
@@ -28,8 +28,17 @@ class Match(NamedTuple):
     size: int
 
 class SequenceMatcher(Generic[_T]):
+    @overload
+    def __init__(self, isjunk: Callable[[_T], bool] | None, a: Sequence[_T], b: Sequence[_T], autojunk: bool = ...) -> None: ...
+    @overload
+    def __init__(self, *, a: Sequence[_T], b: Sequence[_T], autojunk: bool = ...) -> None: ...
+    @overload
     def __init__(
-        self, isjunk: Callable[[_T], bool] | None = ..., a: Sequence[_T] = ..., b: Sequence[_T] = ..., autojunk: bool = ...
+        self: SequenceMatcher[str],
+        isjunk: Callable[[str], bool] | None = ...,
+        a: Sequence[str] = ...,
+        b: Sequence[str] = ...,
+        autojunk: bool = ...,
     ) -> None: ...
     def set_seqs(self, a: Sequence[_T], b: Sequence[_T]) -> None: ...
     def set_seq1(self, a: Sequence[_T]) -> None: ...

diff --git a/stdlib/mailbox.pyi b/stdlib/mailbox.pyi
@@ -46,9 +46,10 @@ class Mailbox(Generic[_MessageT]):
 
     _path: bytes | str  # undocumented
     _factory: Callable[[IO[Any]], _MessageT] | None  # undocumented
-    def __init__(
-        self, path: StrOrBytesPath, factory: Callable[[IO[Any]], _MessageT] | None = ..., create: bool = ...
-    ) -> None: ...
+    @overload
+    def __init__(self, path: StrOrBytesPath, factory: Callable[[IO[Any]], _MessageT], create: bool = ...) -> None: ...
+    @overload
+    def __init__(self, path: StrOrBytesPath, factory: None = ..., create: bool = ...) -> None: ...
     @abstractmethod
     def add(self, message: _MessageData) -> str: ...
     @abstractmethod

diff --git a/stdlib/multiprocessing/shared_memory.pyi b/stdlib/multiprocessing/shared_memory.pyi
@@ -1,7 +1,7 @@
 import sys
 from _typeshed import Self
 from collections.abc import Iterable
-from typing import Any, Generic, TypeVar
+from typing import Any, Generic, TypeVar, overload
 
 if sys.version_info >= (3, 9):
     from types import GenericAlias
@@ -23,7 +23,10 @@ class SharedMemory:
 
 class ShareableList(Generic[_SLT]):
     shm: SharedMemory
-    def __init__(self, sequence: Iterable[_SLT] | None = ..., *, name: str | None = ...) -> None: ...
+    @overload
+    def __init__(self, sequence: None = ..., *, name: str | None = ...) -> None: ...
+    @overload
+    def __init__(self, sequence: Iterable[_SLT], *, name: str | None = ...) -> None: ...
     def __getitem__(self, position: int) -> _SLT: ...
     def __setitem__(self, position: int, value: _SLT) -> None: ...
     def __reduce__(self: Self) -> tuple[Self, tuple[_SLT, ...]]: ...

diff --git a/stdlib/tempfile.pyi b/stdlib/tempfile.pyi
@@ -355,25 +355,27 @@ class TemporaryDirectory(Generic[AnyStr]):
         @overload
         def __init__(
             self: TemporaryDirectory[str],
-            suffix: None = ...,
-            prefix: None = ...,
-            dir: None = ...,
+            suffix: str | None = ...,
+            prefix: str | None = ...,
+            dir: StrPath | None = ...,
             ignore_cleanup_errors: bool = ...,
         ) -> None: ...
         @overload
         def __init__(
-            self,
-            suffix: AnyStr | None = ...,
-            prefix: AnyStr | None = ...,
-            dir: GenericPath[AnyStr] | None = ...,
+            self: TemporaryDirectory[bytes],
+            suffix: bytes | None = ...,
+            prefix: bytes | None = ...,
+            dir: BytesPath | None = ...,
             ignore_cleanup_errors: bool = ...,
         ) -> None: ...
     else:
         @overload
-        def __init__(self: TemporaryDirectory[str], suffix: None = ..., prefix: None = ..., dir: None = ...) -> None: ...
+        def __init__(
+            self: TemporaryDirectory[str], suffix: str | None = ..., prefix: str | None = ..., dir: StrPath | None = ...
+        ) -> None: ...
         @overload
         def __init__(
-            self, suffix: AnyStr | None = ..., prefix: AnyStr | None = ..., dir: GenericPath[AnyStr] | None = ...
+            self: TemporaryDirectory[bytes], suffix: bytes | None = ..., prefix: bytes | None = ..., dir: BytesPath | None = ...
         ) -> None: ...
 
     def cleanup(self) -> None: ...

diff --git a/stubs/flake8-plugin-utils/flake8_plugin_utils/plugin.pyi b/stubs/flake8-plugin-utils/flake8_plugin_utils/plugin.pyi
@@ -1,7 +1,7 @@
 import argparse
 import ast
 from collections.abc import Iterable, Iterator
-from typing import Any, Generic, TypeVar
+from typing import Any, Generic, TypeVar, overload
 from typing_extensions import TypeAlias
 
 FLAKE8_ERROR: TypeAlias = tuple[int, int, str, type[Any]]
@@ -18,7 +18,10 @@ class Error:
 
 class Visitor(ast.NodeVisitor, Generic[TConfig]):
     errors: list[Error]
-    def __init__(self, config: TConfig | None = ...) -> None: ...
+    @overload
+    def __init__(self, config: None = ...) -> None: ...
+    @overload
+    def __init__(self, config: TConfig) -> None: ...
     @property
     def config(self) -> TConfig: ...
     def error_from_node(self, error: type[Error], node: ast.AST, **kwargs: Any) -> None: ...

diff --git a/tests/stubtest_allowlists/py3_common.txt b/tests/stubtest_allowlists/py3_common.txt
@@ -88,7 +88,6 @@ ctypes.memset  # CFunctionType
 ctypes.pointer  # imported C function
 ctypes.string_at  # docstring argument name is wrong
 ctypes.wstring_at  # docstring argument name is wrong
-difflib.SequenceMatcher.__init__  # mypy default value for generic parameter issues. See https://github.com/python/mypy/issues/3737
 distutils.command.bdist_packager  # It exists in docs as package name but not in code except as a mention in a comment.
 distutils.version.Version._cmp  # class should have declared this
 distutils.version.Version.parse  # class should have declared this