remove typing dependencies (#1126)

Summary:
This PR removes the `typing_extensions` and `typing_inspect` dependencies as we can now rely on the built-in `typing` module since Python 3.9.

Test Plan:
existing tests

libcst/_exceptions.py

@@ -4,9 +4,7 @@
 # LICENSE file in the root directory of this source tree.
 
 from enum import auto, Enum
-from typing import Any, Callable, Iterable, Optional, Sequence, Tuple, Union
-
-from typing_extensions import final
+from typing import Any, Callable, final, Iterable, Optional, Sequence, Tuple, Union
 
 from libcst._parser.parso.pgen2.generator import ReservedString
 from libcst._parser.parso.python.token import PythonTokenTypes, TokenType

libcst/_nodes/expression.py

@@ -15,9 +15,7 @@ from tokenize import (
     Imagnumber as IMAGNUMBER_RE,
     Intnumber as INTNUMBER_RE,
 )
-from typing import Callable, Generator, Optional, Sequence, Union
-
-from typing_extensions import Literal
+from typing import Callable, Generator, Literal, Optional, Sequence, Union
 
 from libcst._add_slots import add_slots
 from libcst._maybe_sentinel import MaybeSentinel

libcst/_type_enforce.py

@@ -5,17 +5,20 @@
 
 from typing import (
     Any,
+    ClassVar,
     ForwardRef,
+    get_args,
+    get_origin,
     Iterable,
+    Literal,
     Mapping,
     MutableMapping,
     MutableSequence,
     Tuple,
+    TypeVar,
+    Union,
 )
 
-from typing_extensions import Literal
-from typing_inspect import get_args, get_origin, is_classvar, is_typevar, is_union_type
-
 
 def is_value_of_type(  # noqa: C901 "too complex"
     # pyre-fixme[2]: Parameter annotation cannot be `Any`.
@@ -48,11 +51,11 @@ def is_value_of_type(  # noqa: C901 "too complex"
     - Forward Refs -- use `typing.get_type_hints` to resolve these
     - Type[...]
     """
-    if is_classvar(expected_type):
+    if expected_type is ClassVar or get_origin(expected_type) is ClassVar:
         classvar_args = get_args(expected_type)
         expected_type = (classvar_args[0] or Any) if classvar_args else Any
 
-    if is_typevar(expected_type):
+    if type(expected_type) is TypeVar:
         # treat this the same as Any
         # TODO: evaluate bounds
         return True
@@ -62,13 +65,13 @@ def is_value_of_type(  # noqa: C901 "too complex"
     if expected_origin_type == Any:
         return True
 
-    elif is_union_type(expected_type):
+    elif expected_type is Union or get_origin(expected_type) is Union:
         return any(
             is_value_of_type(value, subtype) for subtype in expected_type.__args__
         )
 
     elif isinstance(expected_origin_type, type(Literal)):
-        literal_values = get_args(expected_type, evaluate=True)
+        literal_values = get_args(expected_type)
         return any(value == literal for literal in literal_values)
 
     elif isinstance(expected_origin_type, ForwardRef):
@@ -82,14 +85,11 @@ def is_value_of_type(  # noqa: C901 "too complex"
         if not isinstance(value, tuple):
             return False
 
-        type_args = get_args(expected_type, evaluate=True)
+        type_args = get_args(expected_type)
         if len(type_args) == 0:
             # `Tuple` (no subscript) is implicitly `Tuple[Any, ...]`
             return True
 
-        if type_args is None:
-            return True
-
         if len(value) != len(type_args):
             return False
         # TODO: Handle `Tuple[T, ...]` like `Iterable[T]`
@@ -106,7 +106,7 @@ def is_value_of_type(  # noqa: C901 "too complex"
         if not issubclass(type(value), expected_origin_type):
             return False
 
-        type_args = get_args(expected_type, evaluate=True)
+        type_args = get_args(expected_type)
         if len(type_args) == 0:
             # `Mapping` (no subscript) is implicitly `Mapping[Any, Any]`.
             return True
@@ -143,7 +143,7 @@ def is_value_of_type(  # noqa: C901 "too complex"
         if not issubclass(type(value), expected_origin_type):
             return False
 
-        type_args = get_args(expected_type, evaluate=True)
+        type_args = get_args(expected_type)
         if len(type_args) == 0:
             # `Iterable` (no subscript) is implicitly `Iterable[Any]`.
             return True

libcst/codegen/gen_matcher_classes.py

@@ -443,8 +443,7 @@ generated_code.append("")
 generated_code.append("")
 generated_code.append("# This file was generated by libcst.codegen.gen_matcher_classes")
 generated_code.append("from dataclasses import dataclass")
-generated_code.append("from typing import Optional, Sequence, Union")
-generated_code.append("from typing_extensions import Literal")
+generated_code.append("from typing import Literal, Optional, Sequence, Union")
 generated_code.append("import libcst as cst")
 generated_code.append("")
 generated_code.append(

libcst/codemod/commands/convert_type_comments.py

@@ -11,8 +11,6 @@ import functools
 import sys
 from typing import cast, Dict, List, Optional, Sequence, Set, Tuple, Union
 
-from typing_extensions import TypeAlias
-
 import libcst as cst
 import libcst.matchers as m
 from libcst.codemod import CodemodContext, VisitorBasedCodemodCommand
@@ -143,9 +141,9 @@ class _ArityError(Exception):
     pass
 
 
-UnpackedBindings: TypeAlias = Union[cst.BaseExpression, List["UnpackedBindings"]]
-UnpackedAnnotations: TypeAlias = Union[str, List["UnpackedAnnotations"]]
-TargetAnnotationPair: TypeAlias = Tuple[cst.BaseExpression, str]
+UnpackedBindings = Union[cst.BaseExpression, List["UnpackedBindings"]]
+UnpackedAnnotations = Union[str, List["UnpackedAnnotations"]]
+TargetAnnotationPair = Tuple[cst.BaseExpression, str]
 
 
 class AnnotationSpreader:

libcst/matchers/__init__.py

@@ -6,9 +6,7 @@
 
 # This file was generated by libcst.codegen.gen_matcher_classes
 from dataclasses import dataclass
-from typing import Optional, Sequence, Union
-
-from typing_extensions import Literal
+from typing import Literal, Optional, Sequence, Union
 
 import libcst as cst
 from libcst.matchers._decorators import call_if_inside, call_if_not_inside, leave, visit

libcst/tests/test_type_enforce.py

@@ -11,6 +11,7 @@ from typing import (
     Dict,
     Iterable,
     List,
+    Literal,
     Mapping,
     MutableMapping,
     NamedTuple,
@@ -23,8 +24,6 @@ from typing import (
     Union,
 )
 
-from typing_extensions import Literal
-
 from libcst._type_enforce import is_value_of_type
 from libcst.testing.utils import data_provider, UnitTest
 

pyproject.toml

@@ -16,11 +16,7 @@ classifiers = [
     "Programming Language :: Python :: 3.12",
 ]
 requires-python = ">=3.9"
-dependencies = [
-    "typing_extensions>=3.7.4.2",
-    "typing_inspect>=0.4.0",
-    "pyyaml>=5.2",
-]
+dependencies = ["pyyaml>=5.2"]
 
 [project.optional-dependencies]
 dev = [