change ast files to use new union syntax (#5880)

stdlib/ast.pyi

@@ -8,7 +8,7 @@
 # sys.
 import sys
 import typing as _typing
-from typing import Any, Iterator, Optional, TypeVar, Union, overload
+from typing import Any, Iterator, TypeVar, overload
 from typing_extensions import Literal
 
 from _ast import *  # type: ignore
@@ -150,7 +150,7 @@ class NodeVisitor:
 class NodeTransformer(NodeVisitor):
     def generic_visit(self, node: AST) -> AST: ...
     # TODO: Override the visit_* methods with better return types.
-    #       The usual return type is Optional[AST], but Iterable[AST]
+    #       The usual return type is AST | None, but Iterable[AST]
     #       is also allowed in some cases -- this needs to be mapped.
 
 _T = TypeVar("_T", bound=AST)
@@ -158,28 +158,28 @@ _T = TypeVar("_T", bound=AST)
 if sys.version_info >= (3, 8):
     @overload
     def parse(
-        source: Union[str, bytes],
-        filename: Union[str, bytes] = ...,
+        source: str | bytes,
+        filename: str | bytes = ...,
         mode: Literal["exec"] = ...,
         *,
         type_comments: bool = ...,
-        feature_version: Union[None, int, _typing.Tuple[int, int]] = ...,
+        feature_version: None | int | _typing.Tuple[int, int] = ...,
     ) -> Module: ...
     @overload
     def parse(
-        source: Union[str, bytes],
-        filename: Union[str, bytes] = ...,
+        source: str | bytes,
+        filename: str | bytes = ...,
         mode: str = ...,
         *,
         type_comments: bool = ...,
-        feature_version: Union[None, int, _typing.Tuple[int, int]] = ...,
+        feature_version: None | int | _typing.Tuple[int, int] = ...,
     ) -> AST: ...
 
 else:
     @overload
-    def parse(source: Union[str, bytes], filename: Union[str, bytes] = ..., mode: Literal["exec"] = ...) -> Module: ...
+    def parse(source: str | bytes, filename: str | bytes = ..., mode: Literal["exec"] = ...) -> Module: ...
     @overload
-    def parse(source: Union[str, bytes], filename: Union[str, bytes] = ..., mode: str = ...) -> AST: ...
+    def parse(source: str | bytes, filename: str | bytes = ..., mode: str = ...) -> AST: ...
 
 if sys.version_info >= (3, 9):
     def unparse(ast_obj: AST) -> str: ...
@@ -188,20 +188,20 @@ def copy_location(new_node: _T, old_node: AST) -> _T: ...
 
 if sys.version_info >= (3, 9):
     def dump(
-        node: AST, annotate_fields: bool = ..., include_attributes: bool = ..., *, indent: Union[int, str, None] = ...
+        node: AST, annotate_fields: bool = ..., include_attributes: bool = ..., *, indent: int | str | None = ...
     ) -> str: ...
 
 else:
     def dump(node: AST, annotate_fields: bool = ..., include_attributes: bool = ...) -> str: ...
 
 def fix_missing_locations(node: _T) -> _T: ...
-def get_docstring(node: AST, clean: bool = ...) -> Optional[str]: ...
+def get_docstring(node: AST, clean: bool = ...) -> str | None: ...
 def increment_lineno(node: _T, n: int = ...) -> _T: ...
 def iter_child_nodes(node: AST) -> Iterator[AST]: ...
 def iter_fields(node: AST) -> Iterator[_typing.Tuple[str, Any]]: ...
-def literal_eval(node_or_string: Union[str, AST]) -> Any: ...
+def literal_eval(node_or_string: str | AST) -> Any: ...
 
 if sys.version_info >= (3, 8):
-    def get_source_segment(source: str, node: AST, *, padded: bool = ...) -> Optional[str]: ...
+    def get_source_segment(source: str, node: AST, *, padded: bool = ...) -> str | None: ...
 
 def walk(node: AST) -> Iterator[AST]: ...