fix: work in progress

Author: cmp0xff

pandas-stubs/core/frame.pyi

@@ -19,6 +19,7 @@ from typing import (
     Generic,
     Literal,
     NoReturn,
+    TypeVar,
     final,
     overload,
 )
@@ -165,6 +166,8 @@ from pandas._typing import (
 from pandas.io.formats.style import Styler
 from pandas.plotting import PlotAccessor
 
+_T_MUTABLE_MAPPING = TypeVar("_T_MUTABLE_MAPPING", bound=MutableMapping, covariant=True)
+
 class _iLocIndexerFrame(_iLocIndexer, Generic[_T]):
     @overload
     def __getitem__(self, idx: tuple[int, int]) -> Scalar: ...
@@ -396,9 +399,9 @@ class DataFrame(NDFrame, OpsMixin, _GetItemHack):
         self,
         orient: Literal["records"],
         *,
-        into: MutableMapping | type[MutableMapping],
+        into: _T_MUTABLE_MAPPING | type[_T_MUTABLE_MAPPING],
         index: Literal[True] = ...,
-    ) -> list[MutableMapping[Hashable, Any]]: ...
+    ) -> list[_T_MUTABLE_MAPPING]: ...
     @overload
     def to_dict(
         self,
@@ -412,33 +415,33 @@ class DataFrame(NDFrame, OpsMixin, _GetItemHack):
         self,
         orient: Literal["dict", "list", "series", "index"],
         *,
-        into: MutableMapping | type[MutableMapping],
+        into: _T_MUTABLE_MAPPING | type[_T_MUTABLE_MAPPING],
         index: Literal[True] = ...,
-    ) -> MutableMapping[Hashable, Any]: ...
+    ) -> _T_MUTABLE_MAPPING: ...
     @overload
     def to_dict(
         self,
         orient: Literal["split", "tight"],
         *,
-        into: MutableMapping | type[MutableMapping],
+        into: _T_MUTABLE_MAPPING | type[_T_MUTABLE_MAPPING],
         index: bool = ...,
-    ) -> MutableMapping[Hashable, Any]: ...
+    ) -> _T_MUTABLE_MAPPING: ...
     @overload
     def to_dict(
         self,
         orient: Literal["dict", "list", "series", "index"] = ...,
         *,
-        into: MutableMapping | type[MutableMapping],
+        into: _T_MUTABLE_MAPPING | type[_T_MUTABLE_MAPPING],
         index: Literal[True] = ...,
-    ) -> MutableMapping[Hashable, Any]: ...
+    ) -> _T_MUTABLE_MAPPING: ...
     @overload
     def to_dict(
         self,
         orient: Literal["split", "tight"] = ...,
         *,
-        into: MutableMapping | type[MutableMapping],
+        into: _T_MUTABLE_MAPPING | type[_T_MUTABLE_MAPPING],
         index: bool = ...,
-    ) -> MutableMapping[Hashable, Any]: ...
+    ) -> _T_MUTABLE_MAPPING: ...
     @overload
     def to_dict(
         self,

tests/test_frame.py

@@ -3643,20 +3643,20 @@ def test_to_dict() -> None:
     check(assert_type(DF.to_dict("split"), dict[Hashable, Any]), dict)
 
     target: MutableMapping = defaultdict(list)
-    check(
-        assert_type(DF.to_dict(into=target), MutableMapping[Hashable, Any]), defaultdict
-    )
+    check(assert_type(DF.to_dict(into=target), defaultdict[Any, list]), defaultdict)
+    # check(
+    #     assert_type(DF.to_dict("index", into=target), MutableMapping[Hashable, MutableMapping[Hashable, Any]]), defaultdict
+    # )
+
     target = defaultdict(list)
     check(
-        assert_type(DF.to_dict("tight", into=target), MutableMapping[Hashable, Any]),
+        assert_type(DF.to_dict("tight", into=target), defaultdict[Any, list]),
         defaultdict,
     )
     target = defaultdict(list)
     check(assert_type(DF.to_dict("records"), list[dict[Hashable, Any]]), list)
     check(
-        assert_type(
-            DF.to_dict("records", into=target), list[MutableMapping[Hashable, Any]]
-        ),
+        assert_type(DF.to_dict("records", into=target), list[defaultdict[Any, list]]),
         list,
     )
     if TYPE_CHECKING_INVALID_USAGE: