Fix property access for function types

mypy/checkmember.py

@@ -936,7 +936,18 @@ def analyze_var(
         ):
             # Unwrap nonmember similar to class-level access
             result = p_result.args[0]
-    if result and not (implicit or var.info.is_protocol and is_instance_var(var)):
+    dataclass_metadata = var.info.metadata.get("dataclass", {})
+    is_dataclass_field = any(
+        attribute.get("name") == name for attribute in dataclass_metadata.get("attributes", [])
+    )
+    # A read-only property has already applied descriptor access to its getter
+    # result. Dataclass fields are represented as synthetic properties, but
+    # their descriptor access still needs to happen on instance reads.
+    if (
+        result
+        and not (var.is_property and not var.is_settable_property and not is_dataclass_field)
+        and not (implicit or var.info.is_protocol and is_instance_var(var))
+    ):
         result = analyze_descriptor_access(result, mx)
     if hook:
         result = hook(

test-data/unit/check-classes.test

@@ -9727,3 +9727,32 @@ def f() -> None:
     class X:
         ...
     undefined  # E: Name "undefined" is not defined
+
+[case testPropertyReturningFunctionType]
+from types import FunctionType
+
+class FuncWrap:
+    def __init__(self, func: object) -> None:
+        if not isinstance(func, FunctionType):
+            raise TypeError()
+        self._func = func
+
+    @property
+    def __func__(self) -> FunctionType:
+        return self._func
+
+def good() -> int:
+    return 1
+
+wrapped = FuncWrap(good)
+assert isinstance(wrapped.__func__, FunctionType)
+[builtins fixtures/property-function.pyi]
+[file types.pyi]
+from typing import final
+
+@final
+class FunctionType:
+    def __get__(self, instance: object, owner: type | None = ...) -> MethodType: ...
+
+@final
+class MethodType: ...

test-data/unit/fixtures/property-function.pyi

@@ -0,0 +1,22 @@
+from typing import Any
+
+class object:
+    def __init__(self) -> None: ...
+
+class type:
+    def __init__(self, x: Any) -> None: ...
+
+class property:
+    def __init__(self, fget: Any = ...) -> None: ...
+
+class BaseException: ...
+class Exception(BaseException): ...
+class TypeError(Exception): ...
+
+class int: ...
+class str: ...
+class dict: ...
+class tuple: ...
+class ellipsis: ...
+
+def isinstance(x: object, t: Any) -> bool: ...