Improve warnings stubs (#3501)

* merge 2and3 for _warnings

* move warn and warn_explicit into _warnings

stdlib/2/_warnings.pyi

@@ -1,16 +0,0 @@
-from typing import Any, Dict, List, Optional, Tuple, Type
-
-default_action: str
-filters: List[Tuple[Any, ...]]
-once_registry: Dict[Any, Any]
-
-def warn(message: Warning, category: Optional[Type[Warning]] = ..., stacklevel: int = ...) -> None: ...
-def warn_explicit(
-    message: Warning,
-    category: Optional[Type[Warning]],
-    filename: str,
-    lineno: int,
-    module: Any = ...,
-    registry: Dict[Any, Any] = ...,
-    module_globals: Dict[Any, Any] = ...,
-) -> None: ...

stdlib/2and3/_warnings.pyi

@@ -0,0 +1,34 @@
+import sys
+from typing import Any, Dict, List, Optional, Tuple, Type, Union, overload
+
+if sys.version_info >= (3, 0):
+    _defaultaction: str
+    _onceregistry: Dict[Any, Any]
+else:
+    default_action: str
+    once_registry: Dict[Any, Any]
+filters: List[Tuple[Any, ...]]
+@overload
+def warn(message: str, category: Optional[Type[Warning]] = ..., stacklevel: int = ...) -> None: ...
+@overload
+def warn(message: Warning, category: Any = ..., stacklevel: int = ...) -> None: ...
+@overload
+def warn_explicit(
+    message: str,
+    category: Type[Warning],
+    filename: str,
+    lineno: int,
+    module: Optional[str] = ...,
+    registry: Optional[Dict[Union[str, Tuple[str, Type[Warning], int]], int]] = ...,
+    module_globals: Optional[Dict[str, Any]] = ...,
+) -> None: ...
+@overload
+def warn_explicit(
+    message: Warning,
+    category: Any,
+    filename: str,
+    lineno: int,
+    module: Optional[str] = ...,
+    registry: Optional[Dict[Union[str, Tuple[str, Type[Warning], int]], int]] = ...,
+    module_globals: Optional[Dict[str, Any]] = ...,
+) -> None: ...

stdlib/2and3/warnings.pyi

@@ -1,38 +1,17 @@
-# Stubs for warnings
-
-import sys
-from typing import Any, Dict, List, NamedTuple, Optional, overload, TextIO, Tuple, Type, Union
+from typing import List, NamedTuple, Optional, overload, TextIO, Type
 from types import ModuleType, TracebackType
+from typing_extensions import Literal
 
-if sys.version_info >= (3, 8):
-    from typing import Literal
-else:
-    from typing_extensions import Literal
+from _warnings import warn as warn, warn_explicit as warn_explicit
 
-@overload
-def warn(message: str, category: Optional[Type[Warning]] = ..., stacklevel: int = ...) -> None: ...
-@overload
-def warn(message: Warning, category: Any = ..., stacklevel: int = ...) -> None: ...
-@overload
-def warn_explicit(message: str, category: Type[Warning],
-                  filename: str, lineno: int, module: Optional[str] = ...,
-                  registry: Optional[Dict[Union[str, Tuple[str, Type[Warning], int]], int]] = ...,
-                  module_globals: Optional[Dict[str, Any]] = ...) -> None: ...
-@overload
-def warn_explicit(message: Warning, category: Any,
-                  filename: str, lineno: int, module: Optional[str] = ...,
-                  registry: Optional[Dict[Union[str, Tuple[str, Type[Warning], int]], int]] = ...,
-                  module_globals: Optional[Dict[str, Any]] = ...) -> None: ...
-def showwarning(message: str, category: Type[Warning], filename: str,
-                lineno: int, file: Optional[TextIO] = ...,
-                line: Optional[str] = ...) -> None: ...
-def formatwarning(message: str, category: Type[Warning], filename: str,
-                  lineno: int, line: Optional[str] = ...) -> str: ...
-def filterwarnings(action: str, message: str = ...,
-                   category: Type[Warning] = ..., module: str = ...,
-                   lineno: int = ..., append: bool = ...) -> None: ...
-def simplefilter(action: str, category: Type[Warning] = ..., lineno: int = ...,
-                 append: bool = ...) -> None: ...
+def showwarning(
+    message: str, category: Type[Warning], filename: str, lineno: int, file: Optional[TextIO] = ..., line: Optional[str] = ...
+) -> None: ...
+def formatwarning(message: str, category: Type[Warning], filename: str, lineno: int, line: Optional[str] = ...) -> str: ...
+def filterwarnings(
+    action: str, message: str = ..., category: Type[Warning] = ..., module: str = ..., lineno: int = ..., append: bool = ...
+) -> None: ...
+def simplefilter(action: str, category: Type[Warning] = ..., lineno: int = ..., append: bool = ...) -> None: ...
 def resetwarnings() -> None: ...
 
 class _Record(NamedTuple):
@@ -51,9 +30,9 @@ class catch_warnings:
     @overload
     def __new__(cls, *, record: bool, module: Optional[ModuleType] = ...) -> catch_warnings: ...
     def __enter__(self) -> Optional[List[_Record]]: ...
-    def __exit__(self, exc_type: Optional[Type[BaseException]],
-                 exc_val: Optional[BaseException],
-                 exc_tb: Optional[TracebackType]) -> None: ...
+    def __exit__(
+        self, exc_type: Optional[Type[BaseException]], exc_val: Optional[BaseException], exc_tb: Optional[TracebackType]
+    ) -> None: ...
 
 class _catch_warnings_without_records(catch_warnings):
     def __enter__(self) -> None: ...

stdlib/3/_warnings.pyi

@@ -1,11 +0,0 @@
-from typing import Any, Dict, List, Optional, Tuple, Type
-
-_defaultaction: str
-_onceregistry: Dict[Any, Any]
-filters: List[Tuple[Any, ...]]
-
-def warn(message: Warning, category: Optional[Type[Warning]] = ..., stacklevel: int = ...) -> None: ...
-def warn_explicit(message: Warning, category: Optional[Type[Warning]],
-                  filename: str, lineno: int,
-                  module: Any = ..., registry: Dict[Any, Any] = ...,
-                  module_globals: Dict[Any, Any] = ...) -> None: ...