Use `ast.parse` from the standard library

sphinx/domains/python.py

@@ -21,7 +21,6 @@ from sphinx.directives import ObjectDescription
 from sphinx.domains import Domain, Index, IndexEntry, ObjType
 from sphinx.environment import BuildEnvironment
 from sphinx.locale import _, __
-from sphinx.pycode.ast import parse as ast_parse
 from sphinx.roles import XRefRole
 from sphinx.util import logging
 from sphinx.util.docfields import Field, GroupedField, TypedField
@@ -206,7 +205,7 @@ def _parse_annotation(annotation: str, env: BuildEnvironment) -> List[Node]:
             raise SyntaxError  # unsupported syntax
 
     try:
-        tree = ast_parse(annotation)
+        tree = ast.parse(annotation, type_comments=True)
         result: List[Node] = []
         for node in unparse(tree):
             if isinstance(node, nodes.literal):

sphinx/ext/autodoc/preserve_defaults.py

@@ -11,7 +11,6 @@ from typing import Any, Dict, List, Optional
 import sphinx
 from sphinx.application import Sphinx
 from sphinx.locale import __
-from sphinx.pycode.ast import parse as ast_parse
 from sphinx.pycode.ast import unparse as ast_unparse
 from sphinx.util import logging
 
@@ -36,10 +35,10 @@ def get_function_def(obj: Any) -> Optional[ast.FunctionDef]:
         if source.startswith((' ', r'\t')):
             # subject is placed inside class or block.  To read its docstring,
             # this adds if-block before the declaration.
-            module = ast_parse('if True:\n' + source)
+            module = ast.parse('if True:\n' + source)
             return module.body[0].body[0]  # type: ignore
         else:
-            module = ast_parse(source)
+            module = ast.parse(source)
             return module.body[0]  # type: ignore
     except (OSError, TypeError):  # failed to load source code
         return None

sphinx/ext/autodoc/type_comment.py

@@ -7,7 +7,6 @@ from typing import Any, Dict, List, cast
 import sphinx
 from sphinx.application import Sphinx
 from sphinx.locale import __
-from sphinx.pycode.ast import parse as ast_parse
 from sphinx.pycode.ast import unparse as ast_unparse
 from sphinx.util import inspect, logging
 
@@ -86,14 +85,14 @@ def get_type_comment(obj: Any, bound_method: bool = False) -> Signature:
         if source.startswith((' ', r'\t')):
             # subject is placed inside class or block.  To read its docstring,
             # this adds if-block before the declaration.
-            module = ast_parse('if True:\n' + source)
+            module = ast.parse('if True:\n' + source, type_comments=True)
             subject = cast(ast.FunctionDef, module.body[0].body[0])  # type: ignore
         else:
-            module = ast_parse(source)
-            subject = cast(ast.FunctionDef, module.body[0])  # type: ignore
+            module = ast.parse(source, type_comments=True)
+            subject = cast(ast.FunctionDef, module.body[0])
 
         if getattr(subject, "type_comment", None):
-            function = ast_parse(subject.type_comment, mode='func_type')
+            function = ast.parse(subject.type_comment, mode='func_type', type_comments=True)
             return signature_from_ast(subject, bound_method, function)  # type: ignore
         else:
             return None

sphinx/pycode/ast.py

@@ -1,8 +1,11 @@
 """Helpers for AST (Abstract Syntax Tree)."""
 
 import ast
+import warnings
 from typing import Dict, List, Optional, Type, overload
 
+from sphinx.deprecation import RemovedInSphinx70Warning
+
 OPERATORS: Dict[Type[ast.AST], str] = {
     ast.Add: "+",
     ast.And: "and",
@@ -28,6 +31,10 @@ OPERATORS: Dict[Type[ast.AST], str] = {
 
 def parse(code: str, mode: str = 'exec') -> "ast.AST":
     """Parse the *code* using the built-in ast module."""
+    warnings.warn(
+        "'sphinx.pycode.ast.parse' is deprecated, use 'ast.parse' instead.",
+        RemovedInSphinx70Warning, stacklevel=2
+    )
     try:
         return ast.parse(code, mode=mode, type_comments=True)
     except SyntaxError:

sphinx/pycode/parser.py

@@ -11,7 +11,6 @@ from token import DEDENT, INDENT, NAME, NEWLINE, NUMBER, OP, STRING
 from tokenize import COMMENT, NL
 from typing import Any, Dict, List, Optional, Tuple
 
-from sphinx.pycode.ast import parse as ast_parse
 from sphinx.pycode.ast import unparse as ast_unparse
 
 comment_re = re.compile('^\\s*#: ?(.*)\r?\n?$')
@@ -552,7 +551,7 @@ class Parser:
 
     def parse_comments(self) -> None:
         """Parse the code and pick up comments."""
-        tree = ast_parse(self.code)
+        tree = ast.parse(self.code, type_comments=True)
         picker = VariableCommentPicker(self.code.splitlines(True), self.encoding)
         picker.visit(tree)
         self.annotations = picker.annotations

sphinx/util/inspect.py

@@ -333,8 +333,7 @@ def isproperty(obj: Any) -> bool:
 
 def isgenericalias(obj: Any) -> bool:
     """Check if the object is GenericAlias."""
-    if (hasattr(typing, '_GenericAlias') and  # only for py37+
-            isinstance(obj, typing._GenericAlias)):  # type: ignore
+    if isinstance(obj, typing._GenericAlias):  # type: ignore
         return True
     elif (hasattr(types, 'GenericAlias') and  # only for py39+
           isinstance(obj, types.GenericAlias)):  # type: ignore