Add support for the new type argument.

src/attr/__init__.pyi

@@ -1,15 +1,15 @@
-from typing import Any, Callable, Dict, Iterable, List, Optional, Mapping, Tuple, Type, TypeVar, Union, overload
+from typing import Any, Callable, Dict, Generic, Iterable, List, Optional, Mapping, Tuple, Type, TypeVar, Union, overload
 from . import exceptions
 from . import filters
 from . import converters
 from . import validators
 
 # typing --
 
-C = TypeVar('C', bound=type)
-M = TypeVar('M', bound=Mapping)
-T = TypeVar('T', bound=tuple)
-I = TypeVar('I')
+_T = TypeVar('_T')
+_C = TypeVar('_C', bound=type)
+_M = TypeVar('_M', bound=Mapping)
+_TT = TypeVar('_TT', bound=tuple)
 
 ValidatorType = Callable[[object, 'Attribute', Any], Any]
 ConverterType = Callable[[Any], Any]
@@ -21,41 +21,41 @@ class _CountingAttr: ...
 
 NOTHING : object
 
+class Factory(Generic[_T]):
+    factory : Union[Callable[[], _T], Callable[[object], _T]]
+    takes_self : bool
+    def __init__(self, factory: Union[Callable[[], _T], Callable[[object], _T]], takes_self: bool = ...) -> None: ...
+
 class Attribute:
-    __slots__ = (
-        "name", "default", "validator", "repr", "cmp", "hash", "init",
-        "convert", "metadata",
-    )
-    def __init__(self, name: str, default: Any, validator: Optional[Union[ValidatorType, List[ValidatorType]]], repr: bool, cmp: bool, hash: Optional[bool], init: bool, convert: Optional[ConverterType] = ..., metadata: Mapping = ...) -> None: ...
+    __slots__ = ("name", "default", "validator", "repr", "cmp", "hash", "init", "convert", "metadata", "type")
+    def __init__(self, name: str, default: Any, validator: Optional[Union[ValidatorType, List[ValidatorType]]], repr: bool, cmp: bool, hash: Optional[bool], init: bool, convert: Optional[ConverterType] = ..., metadata: Mapping = ..., type: Union[type, Factory] = ...) -> None: ...
 
-# NOTE: the stub for `attr` returns Any so that static analysis passes when used in the form:  x : int = attr()
+# NOTE: this overload for `attr` returns Any so that static analysis passes when used in the form:  x : int = attr()
+@overload
 def attr(default: Any = ..., validator: Optional[Union[ValidatorType, List[ValidatorType]]] = ..., repr: bool = ..., cmp: bool = ..., hash: Optional[bool] = ..., init: bool = ..., convert: Optional[ConverterType] = ..., metadata: Mapping = ...) -> Any: ...
+@overload
+def attr(default: Any = ..., validator: Optional[Union[ValidatorType, List[ValidatorType]]] = ..., repr: bool = ..., cmp: bool = ..., hash: Optional[bool] = ..., init: bool = ..., convert: Optional[ConverterType] = ..., metadata: Mapping = ..., type: Union[Type[_T], Factory[_T]] = ...) -> _T: ...
 
 @overload
-def attributes(maybe_cls: C = ..., these: Optional[Dict[str, _CountingAttr]] = ..., repr_ns: Optional[str] = ..., repr: bool = ..., cmp: bool = ..., hash: Optional[bool] = ..., init: bool = ..., slots: bool = ..., frozen: bool = ..., str: bool = ...) -> C: ...
+def attributes(maybe_cls: _C = ..., these: Optional[Dict[str, _CountingAttr]] = ..., repr_ns: Optional[str] = ..., repr: bool = ..., cmp: bool = ..., hash: Optional[bool] = ..., init: bool = ..., slots: bool = ..., frozen: bool = ..., str: bool = ...) -> _C: ...
 @overload
-def attributes(maybe_cls: None = ..., these: Optional[Dict[str, _CountingAttr]] = ..., repr_ns: Optional[str] = ..., repr: bool = ..., cmp: bool = ..., hash: Optional[bool] = ..., init: bool = ..., slots: bool = ..., frozen: bool = ..., str: bool = ...) -> Callable[[C], C]: ...
+def attributes(maybe_cls: None = ..., these: Optional[Dict[str, _CountingAttr]] = ..., repr_ns: Optional[str] = ..., repr: bool = ..., cmp: bool = ..., hash: Optional[bool] = ..., init: bool = ..., slots: bool = ..., frozen: bool = ..., str: bool = ...) -> Callable[[_C], _C]: ...
 
 def fields(cls: type) -> Tuple[Attribute, ...]: ...
 def validate(inst: object) -> None: ...
 
-class Factory:
-    factory : Union[Callable[[Any], Any], Callable[[object, Any], Any]]
-    takes_self : bool
-    def __init__(self, factory: Union[Callable[[Any], Any], Callable[[object, Any], Any]], takes_self: bool = ...) -> None: ...
-
 def make_class(name, attrs: Union[List[_CountingAttr], Dict[str, _CountingAttr]], bases: Tuple[type, ...] = ..., **attributes_arguments) -> type: ...
 
 def and_(*validators: Iterable[ValidatorType]) -> ValidatorType: ...
 
 # _funcs --
 
 # FIXME: having problems assigning a default to the factory typevars
-def asdict(inst: object, recurse: bool = ..., filter: Optional[FilterType] = ..., dict_factory: Callable[[], M] = ..., retain_collection_types: bool = ...) -> M: ...
-def astuple(inst: object, recurse: bool = ..., filter: Optional[FilterType] = ..., tuple_factory: Callable[[Iterable], T] = ..., retain_collection_types: bool = ...) -> T: ...
+def asdict(inst: object, recurse: bool = ..., filter: Optional[FilterType] = ..., dict_factory: Callable[[], _M] = ..., retain_collection_types: bool = ...) -> _M: ...
+def astuple(inst: object, recurse: bool = ..., filter: Optional[FilterType] = ..., tuple_factory: Callable[[Iterable], _TT] = ..., retain_collection_types: bool = ...) -> _TT: ...
 def has(cls: type) -> bool: ...
-def assoc(inst: I, **changes) -> I: ...
-def evolve(inst: I, **changes) -> I: ...
+def assoc(inst: _T, **changes) -> _T: ...
+def evolve(inst: _T, **changes) -> _T: ...
 
 # _config --