Add types and functions in types.py that are new in 3.7 (#3066)

* Add types and functions in types.py that are new in 3.7

* Update `resolve_bases` to accept any iterable of objects, and the same
for `new_class` if the version is at least 3.7

* Add comparison overrides implemented by MethodWrapperType

* Fix mypy error due to over-constrained `__eq__`

stdlib/3/types.pyi

@@ -6,7 +6,7 @@
 import sys
 from typing import (
     Any, Awaitable, Callable, Dict, Generic, Iterator, Mapping, Optional, Tuple, TypeVar,
-    Union, overload, Type
+    Union, overload, Type, Iterable
 )
 
 # ModuleType is exported from this module, but for circular import
@@ -156,6 +156,38 @@ class BuiltinFunctionType:
     def __call__(self, *args: Any, **kwargs: Any) -> Any: ...
 BuiltinMethodType = BuiltinFunctionType
 
+if sys.version_info >= (3, 7):
+    class WrapperDescriptorType:
+        __name__: str
+        __qualname__: str
+        __objclass__: type
+        def __call__(self, *args: Any, **kwargs: Any) -> Any: ...
+        def __get__(self, obj: Any, type: type = ...) -> Any: ...
+
+    class MethodWrapperType:
+        __self__: object
+        __name__: str
+        __qualname__: str
+        __objclass__: type
+        def __call__(self, *args: Any, **kwargs: Any) -> Any: ...
+        def __eq__(self, other: Any) -> bool: ...
+        def __ne__(self, other: Any) -> bool: ...
+
+    class MethodDescriptorType:
+        __name__: str
+        __qualname__: str
+        __objclass__: type
+        def __call__(self, *args: Any, **kwargs: Any) -> Any: ...
+        def __get__(self, obj: Any, type: type = ...) -> Any: ...
+
+    class ClassMethodDescriptorType:
+        __name__: str
+        __qualname__: str
+        __objclass__: type
+        def __call__(self, *args: Any, **kwargs: Any) -> Any: ...
+        def __get__(self, obj: Any, type: type = ...) -> Any: ...
+
+
 class TracebackType:
     if sys.version_info >= (3, 7):
         def __init__(self, tb_next: Optional[TracebackType], tb_frame: FrameType, tb_lasti: int, tb_lineno: int) -> None: ...
@@ -199,7 +231,11 @@ class MemberDescriptorType:
     def __set__(self, obj: Any) -> None: ...
     def __delete__(self, obj: Any) -> None: ...
 
-def new_class(name: str, bases: Tuple[type, ...] = ..., kwds: Dict[str, Any] = ..., exec_body: Callable[[Dict[str, Any]], None] = ...) -> type: ...
+if sys.version_info >= (3, 7):
+    def new_class(name: str, bases: Iterable[object] = ..., kwds: Dict[str, Any] = ..., exec_body: Callable[[Dict[str, Any]], None] = ...) -> type: ...
+    def resolve_bases(bases: Iterable[object]) -> Tuple[Any, ...]: ...
+else:
+    def new_class(name: str, bases: Tuple[type, ...] = ..., kwds: Dict[str, Any] = ..., exec_body: Callable[[Dict[str, Any]], None] = ...) -> type: ...
 def prepare_class(name: str, bases: Tuple[type, ...] = ..., kwds: Dict[str, Any] = ...) -> Tuple[type, Dict[str, Any], Dict[str, Any]]: ...
 
 # Actually a different type, but `property` is special and we want that too.