From f105c7921951d19e0a9a3a9ae1726bea25e98e4d Mon Sep 17 00:00:00 2001
From: Alex Waygood <Alex.Waygood@Gmail.com>
Date: Sat, 4 Dec 2021 17:50:47 +0000
Subject: [PATCH] Harmonise `UserDict.__init__` with `dict.__init__` (#6490)

Co-authored-by: Akuli <akuviljanen17@gmail.com>
---
 stdlib/builtins.pyi             |  1 +
 stdlib/collections/__init__.pyi | 16 +++++++++++++---
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/stdlib/builtins.pyi b/stdlib/builtins.pyi
index b8ee4ff38..fb43eefcc 100644
--- a/stdlib/builtins.pyi
+++ b/stdlib/builtins.pyi
@@ -816,6 +816,7 @@ class list(MutableSequence[_T], Generic[_T]):
         def __class_getitem__(cls, __item: Any) -> GenericAlias: ...
 
 class dict(MutableMapping[_KT, _VT], Generic[_KT, _VT]):
+    # __init__ should be kept roughly in line with `collections.UserDict.__init__`, which has similar semantics
     @overload
     def __init__(self: dict[_KT, _VT]) -> None: ...
     @overload
diff --git a/stdlib/collections/__init__.pyi b/stdlib/collections/__init__.pyi
index 8a5c40cd7..5d52641e5 100644
--- a/stdlib/collections/__init__.pyi
+++ b/stdlib/collections/__init__.pyi
@@ -1,6 +1,6 @@
 import sys
 from _collections_abc import dict_items, dict_keys, dict_values
-from _typeshed import Self, SupportsLessThan, SupportsLessThanT
+from _typeshed import Self, SupportsKeysAndGetItem, SupportsLessThan, SupportsLessThanT
 from typing import Any, Dict, Generic, NoReturn, Tuple, Type, TypeVar, overload
 from typing_extensions import SupportsIndex, final
 
@@ -35,9 +35,19 @@ else:
         typename: str, field_names: str | Iterable[str], *, verbose: bool = ..., rename: bool = ..., module: str | None = ...
     ) -> Type[Tuple[Any, ...]]: ...
 
-class UserDict(MutableMapping[_KT, _VT]):
+class UserDict(MutableMapping[_KT, _VT], Generic[_KT, _VT]):
     data: dict[_KT, _VT]
-    def __init__(self, __dict: Mapping[_KT, _VT] | None = ..., **kwargs: _VT) -> None: ...
+    # __init__ should be kept roughly in line with `dict.__init__`, which has the same semantics
+    @overload
+    def __init__(self: UserDict[_KT, _VT], __dict: None = ...) -> None: ...
+    @overload
+    def __init__(self: UserDict[str, _VT], __dict: None = ..., **kwargs: _VT) -> None: ...
+    @overload
+    def __init__(self, __dict: SupportsKeysAndGetItem[_KT, _VT], **kwargs: _VT) -> None: ...
+    @overload
+    def __init__(self, __iterable: Iterable[tuple[_KT, _VT]], **kwargs: _VT) -> None: ...
+    @overload
+    def __init__(self: UserDict[str, str], __iterable: Iterable[list[str]]) -> None: ...
     def __len__(self) -> int: ...
     def __getitem__(self, key: _KT) -> _VT: ...
     def __setitem__(self, key: _KT, item: _VT) -> None: ...