TypeForm

mypy/messages.py

@@ -2740,7 +2740,7 @@ def format_literal_value(typ: LiteralType) -> str:
         else:
             return "Never"
     elif isinstance(typ, TypeType):
-        type_name = "type" if options.use_lowercase_names() else "Type"
+        type_name = typ.name if options.use_lowercase_names() else typ.name.title()
         return f"{type_name}[{format(typ.item)}]"
     elif isinstance(typ, FunctionLike):
         func = typ

mypy/typeanal.py

@@ -69,12 +69,14 @@
     ProperType,
     RawExpressionType,
     RequiredType,
+    SpecialFormType,
     SyntheticTypeVisitor,
     TrivialSyntheticTypeTranslator,
     TupleType,
     Type,
     TypeAliasType,
     TypedDictType,
+    TypeFormType,
     TypeGuardType,
     TypeList,
     TypeOfAny,
@@ -584,6 +586,12 @@ def try_analyze_special_unbound_type(self, t: UnboundType, fullname: str) -> Typ
         elif fullname == "basedtyping.Intersection":
             items = self.anal_array(t.args)
             return IntersectionType.make_intersection(items)
+        elif fullname == "test.SpecialForm":  # TODO:  "basedtyping.SpecialForm
+            item = self.anal_type(t.args[0])
+            return SpecialFormType(item, line=t.line, column=t.column)
+        elif fullname == "test.TypeForm":  # TODO:  "basedtyping.TypeForm
+            item = self.anal_type(t.args[0])
+            return TypeFormType(item, line=t.line, column=t.column)
         elif fullname == "typing.Optional":
             if len(t.args) != 1:
                 self.fail(

mypy/types.py

@@ -3222,6 +3222,8 @@ class TypeType(ProperType):
     assumption).
     """
 
+    name = "type"
+
     __slots__ = ("item",)
 
     # This can't be everything, but it can be a class reference,
@@ -3278,6 +3280,30 @@ def deserialize(cls, data: JsonDict) -> Type:
         return TypeType.make_normalized(deserialize_type(data["item"]))
 
 
+class TypeFormType(TypeType):
+    name = "TypeForm"
+
+    def serialize(self) -> JsonDict:
+        return {".class": "TypeFormType", "item": self.item.serialize()}
+
+    @classmethod
+    def deserialize(cls, data: JsonDict) -> Type:
+        assert data[".class"] == "TypeFormType"
+        return cls(deserialize_type(data["item"]))
+
+
+class SpecialFormType(TypeType):
+    name = "SpecialForm"
+
+    def serialize(self) -> JsonDict:
+        return {".class": "SpecialFormType", "item": self.item.serialize()}
+
+    @classmethod
+    def deserialize(cls, data: JsonDict) -> Type:
+        assert data[".class"] == "SpecialFormType"
+        return cls(deserialize_type(data["item"]))
+
+
 class PlaceholderType(ProperType):
     """Temporary, yet-unknown type during semantic analysis.
 
@@ -3729,8 +3755,9 @@ def visit_ellipsis_type(self, t: EllipsisType) -> str:
 
     def visit_type_type(self, t: TypeType) -> str:
         if not mypy.options._based:
-            return f"Type[{t.item.accept(self)}]"
-        return f"type[{t.item.accept(self)}]"
+            name = t.name.title()
+            return f"{name}[{t.item.accept(self)}]"
+        return f"{t.name}[{t.item.accept(self)}]"
 
     def visit_placeholder_type(self, t: PlaceholderType) -> str:
         return f"<placeholder {t.fullname}>"

mypy/typeshed/stdlib/builtins.pyi

@@ -30,6 +30,7 @@ from _typeshed import (
 )
 from collections.abc import Awaitable, Callable, Iterable, Iterator, MutableSet, Reversible, Set as AbstractSet, Sized
 from io import BufferedRandom, BufferedReader, BufferedWriter, FileIO, TextIOWrapper
+from mypy.types import SpecialFormType
 from types import CodeType, TracebackType, _Cell
 
 # mypy crashes if any of {ByteString, Sequence, MutableSequence, Mapping, MutableMapping} are imported from collections.abc in builtins.pyi
@@ -51,7 +52,7 @@ from typing import (  # noqa: Y022
     SupportsFloat,
     TypeVar,
     overload,
-    type_check_only,
+    type_check_only, Union,
 )
 from typing_extensions import (
     Concatenate,
@@ -1367,7 +1368,7 @@ def iter(__function: Callable[[], _T], __sentinel: object) -> Iterator[_T]: ...
 
 # Keep this alias in sync with unittest.case._ClassInfo
 if sys.version_info >= (3, 10):
-    _ClassInfo: TypeAlias = type | types.UnionType | tuple[_ClassInfo, ...]
+    _ClassInfo: TypeAlias = type | SpecialForm[Union[object]] | types.UnionType | tuple[_ClassInfo, ...]
 else:
     _ClassInfo: TypeAlias = type | tuple[_ClassInfo, ...]
 

mypy/typeshed/stdlib/typing.pyi

@@ -174,21 +174,30 @@ class TypeVar:
 # Used for an undocumented mypy feature. Does not exist at runtime.
 _promote = object()
 
+_TSpecialInstance = TypeVar("_TSpecialForm", bound=_SpecialInstance)
+
+
 # N.B. Keep this definition in sync with typing_extensions._SpecialForm
 @_final
-class _SpecialForm:
-    def __getitem__(self, parameters: Any) -> object: ...
+class _SpecialForm(Generic[_TSpecialInstance]):
+    def __getitem__(self, parameters: Any) -> _TSpecialInstance: ...
     if sys.version_info >= (3, 10):
-        def __or__(self, other: Any) -> _SpecialForm: ...
-        def __ror__(self, other: Any) -> _SpecialForm: ...
+        def __or__(self, other: Any) -> _SpecialForm[_UnionInstance]: ...
+        def __ror__(self, other: Any) -> _SpecialForm[_UnionInstance]: ...
 
 _F = TypeVar("_F", bound=Callable[..., Any])
 _P = _ParamSpec("_P")
 _T = TypeVar("_T")
+_Ts = TypeVarTuple("_Ts")
 
 def overload(func: _F) -> _F: ...
 
-Union: _SpecialForm
+@type_check_only
+class _SpecialInstance(Generic[Unpack[_Ts]]): ...
+@type_check_only
+class _UnionInstance(_SpecialInstance[Unpack[_Ts]]): ...
+
+Union: _SpecialForm[_UnionInstance]
 Generic: _SpecialForm
 # Protocol is only present in 3.8 and later, but mypy needs it unconditionally
 Protocol: _SpecialForm
@@ -819,10 +828,10 @@ if sys.version_info >= (3, 9):
 else:
     def get_type_hints(
         obj: _get_type_hints_obj_allowed_types, globalns: dict[str, Any] | None = None, localns: dict[str, Any] | None = None
-    ) -> dict[str, Any]: ...
+    ) -> dict[str, object]: ...
 
 if sys.version_info >= (3, 8):
-    def get_args(tp: Any) -> tuple[Any, ...]: ...
+    def get_args(tp: Any) -> tuple[object, ...]: ...
 
     if sys.version_info >= (3, 10):
         @overload

mypy/typeshed/stdlib/unittest/case.pyi

@@ -6,7 +6,7 @@ from collections.abc import Callable, Container, Iterable, Mapping, Sequence, Se
 from contextlib import AbstractContextManager
 from re import Pattern
 from types import TracebackType
-from typing import Any, AnyStr, ClassVar, Generic, NamedTuple, NoReturn, Protocol, SupportsAbs, SupportsRound, TypeVar, overload
+from typing import Any, AnyStr, ClassVar, Generic, NamedTuple, NoReturn, Protocol, SupportsAbs, SupportsRound, TypeVar, _UnionInstance, overload
 from typing_extensions import ParamSpec, Self, TypeAlias
 from warnings import WarningMessage
 
@@ -72,7 +72,7 @@ class _SupportsAbsAndDunderGE(SupportsDunderGE[Any], SupportsAbs[Any], Protocol)
 # We can't import it from builtins or pytype crashes,
 # due to the fact that pytype uses a custom builtins stub rather than typeshed's builtins stub
 if sys.version_info >= (3, 10):
-    _ClassInfo: TypeAlias = type | UnionType | tuple[_ClassInfo, ...]
+    _ClassInfo: TypeAlias = type | _UnionInstance | UnionType | tuple[_ClassInfo, ...]
 else:
     _ClassInfo: TypeAlias = type | tuple[_ClassInfo, ...]