Conditionally define the protocol instead

src/attr/__init__.pyi

@@ -8,6 +8,7 @@ from typing import (
     List,
     Mapping,
     Optional,
+    Protocol,
     Sequence,
     Tuple,
     Type,
@@ -26,8 +27,6 @@ from ._cmp import cmp_using as cmp_using
 from ._version_info import VersionInfo
 from ._typing_compat import AttrsInstance_
 
-AttrsInstance = AttrsInstance_
-
 if sys.version_info >= (3, 10):
     from typing import TypeGuard
 else:
@@ -65,6 +64,10 @@ _FieldTransformer = Callable[
 # _ValidatorType from working when passed in a list or tuple.
 _ValidatorArgType = Union[_ValidatorType[_T], Sequence[_ValidatorType[_T]]]
 
+# We subclass this here to keep the protocol's qualified name clean.
+class AttrsInstance(AttrsInstance_, Protocol):
+    pass
+
 # _make --
 
 NOTHING: object

src/attr/_typing_compat.pyi

@@ -2,11 +2,11 @@ from typing import Any, ClassVar, Protocol
 
 MYPY = False
 
-# A protocol to be able to statically accept an attrs class.
-class AttrsInstance(Protocol):
-    __attrs_attrs__: ClassVar[Any]
-
 if MYPY:
-    AttrsInstance_ = AttrsInstance
+    # A protocol to be able to statically accept an attrs class.
+    class AttrsInstance_(Protocol):
+        __attrs_attrs__: ClassVar[Any]
+
 else:
-    AttrsInstance_ = Any
+    class AttrsInstance_(Protocol):
+        pass

tests/test_pyright.py

@@ -91,6 +91,7 @@ def test_pyright_attrsinstance_is_any(tmp_path):
         """\
 import attrs
 
+foo: attrs.AttrsInstance = object()  # We can assign any old object to `AttrsInstance`.
 reveal_type(attrs.AttrsInstance)
 """
     )
@@ -99,7 +100,7 @@ def test_pyright_attrsinstance_is_any(tmp_path):
     expected_diagnostics = {
         PyrightDiagnostic(
             severity="information",
-            message='Type of "attrs.AttrsInstance" is "Any"',
+            message='Type of "attrs.AttrsInstance" is "Type[AttrsInstance]"',
         ),
     }
     assert diagnostics == expected_diagnostics