[typing] Add sys check guard for typing.Self for python < 3.11 (#2911)

Closes #2910

Author: Pierre-Sassoulas

astroid/nodes/scoped_nodes/mixin.py

@@ -6,16 +6,19 @@
 
 from __future__ import annotations
 
+import sys
 from typing import TYPE_CHECKING, overload
 
-from typing_extensions import Self
-
 from astroid.exceptions import ParentMissingError
 from astroid.filter_statements import _filter_stmts
 from astroid.nodes import _base_nodes, scoped_nodes
 from astroid.nodes.scoped_nodes.utils import builtin_lookup
 from astroid.typing import InferenceResult, SuccessfulInferenceResult
 
+if sys.version_info >= (3, 11):
+    from typing import Self
+else:
+    from typing_extensions import Self
 if TYPE_CHECKING:
     from astroid import nodes
 

astroid/nodes/scoped_nodes/scoped_nodes.py

@@ -13,12 +13,11 @@
 import io
 import itertools
 import os
+import sys
 from collections.abc import Generator, Iterable, Iterator, Sequence
 from functools import cached_property, lru_cache
 from typing import TYPE_CHECKING, Any, ClassVar, Literal, NoReturn
 
-from typing_extensions import Self
-
 from astroid import bases, protocols, util
 from astroid.context import (
     CallContext,
@@ -52,6 +51,11 @@
     SuccessfulInferenceResult,
 )
 
+if sys.version_info >= (3, 11):
+    from typing import Self
+else:
+    from typing_extensions import Self
+
 if TYPE_CHECKING:
     from astroid import nodes, objects
     from astroid.nodes import Arguments, Const, NodeNG

astroid/objects.py

@@ -13,12 +13,11 @@
 
 from __future__ import annotations
 
+import sys
 from collections.abc import Generator, Iterator
 from functools import cached_property
 from typing import Any, Literal, NoReturn
 
-from typing_extensions import Self
-
 from astroid import bases, util
 from astroid.context import InferenceContext
 from astroid.exceptions import (
@@ -32,6 +31,11 @@
 from astroid.nodes import node_classes, scoped_nodes
 from astroid.typing import InferenceResult, SuccessfulInferenceResult
 
+if sys.version_info >= (3, 11):
+    from typing import Self
+else:
+    from typing_extensions import Self
+
 
 class FrozenSet(node_classes.BaseContainer):
     """Class representing a FrozenSet composite node."""