Improvements to functools.partial of types (#17898)

hauntsaninja · JukkaL · commit c69294320c6e · 2024-10-09T09:58:48.000+01:00
Fixes #17556 , fixes #17659
diff --git a/mypy/checker.py b/mypy/checker.py
@@ -686,10 +686,10 @@ def extract_callable_type(self, inner_type: Type | None, ctx: Context) -> Callab
             if isinstance(inner_type, TypeVarLikeType):
                 inner_type = get_proper_type(inner_type.upper_bound)
             if isinstance(inner_type, TypeType):
-                if isinstance(inner_type.item, Instance):
-                    inner_type = expand_type_by_instance(
-                        type_object_type(inner_type.item.type, self.named_type), inner_type.item
-                    )
+                inner_type = get_proper_type(
+                    self.expr_checker.analyze_type_type_callee(inner_type.item, ctx)
+                )
+
             if isinstance(inner_type, CallableType):
                 outer_type = inner_type
             elif isinstance(inner_type, Instance):
diff --git a/test-data/unit/check-functools.test b/test-data/unit/check-functools.test
@@ -557,3 +557,39 @@ def bar(f: S) -> S:
     g = functools.partial(f, "foo")
     return f
 [builtins fixtures/primitives.pyi]
+
+
+[case testFunctoolsPartialAbstractType]
+# flags: --python-version 3.9
+from abc import ABC, abstractmethod
+from functools import partial
+
+class A(ABC):
+    def __init__(self) -> None: ...
+    @abstractmethod
+    def method(self) -> None: ...
+
+def f1(cls: type[A]) -> None:
+    cls()
+    partial_cls = partial(cls)
+    partial_cls()
+
+def f2() -> None:
+    A()  # E: Cannot instantiate abstract class "A" with abstract attribute "method"
+    partial_cls = partial(A)  # E: Cannot instantiate abstract class "A" with abstract attribute "method"
+    partial_cls()  # E: Cannot instantiate abstract class "A" with abstract attribute "method"
+[builtins fixtures/tuple.pyi]
+
+
+[case testFunctoolsPartialSelfType]
+from functools import partial
+from typing_extensions import Self
+
+class A:
+    def __init__(self, ts: float, msg: str) -> None: ...
+
+    @classmethod
+    def from_msg(cls, msg: str) -> Self:
+        factory = partial(cls, ts=0)
+        return factory(msg=msg)
+[builtins fixtures/tuple.pyi]
diff --git a/test-data/unit/lib-stub/typing_extensions.pyi b/test-data/unit/lib-stub/typing_extensions.pyi
@@ -43,6 +43,8 @@ Required: _SpecialForm
 NotRequired: _SpecialForm
 ReadOnly: _SpecialForm
 
+Self: _SpecialForm
+
 @final
 class TypeAliasType:
     def __init__(
