Replace typing.List and other aliases w/ builtin equivalents after Python 3.10

docs/guide/builtins.rst

@@ -40,6 +40,7 @@ Built-in Rules
 - :class:`UseAssertIn`
 - :class:`UseAssertIsNotNone`
 - :class:`UseAsyncSleepInAsyncDef`
+- :class:`UseBuiltinTypes`
 - :class:`UseClsInClassmethod`
 - :class:`UseFstring`
 - :class:`UseTypesFromTyping`
@@ -1007,6 +1008,52 @@ Built-in Rules
             from time import sleep
             async def func():
                 sleep(1)
+.. class:: UseBuiltinTypes
+
+    Enforces the use of builtin types instead of their aliases from the ``typing``
+    module in Python 3.10 and later.
+
+    .. attribute:: AUTOFIX
+        :type: Yes
+
+    .. attribute:: PYTHON_VERSION
+        :type: '>= 3.10'
+
+    .. attribute:: VALID
+
+        .. code:: python
+
+            def fuction(list: list[str]) -> None:
+                pass
+        .. code:: python
+
+            def function() -> None:
+                thing: dict[str, str] = {}
+
+    .. attribute:: INVALID
+
+        .. code:: python
+
+            from typing import List
+            def whatever(list: List[str]) -> None:
+                pass
+
+            # suggested fix
+            from typing import List
+            def whatever(list: list[str]) -> None:
+                pass
+
+        .. code:: python
+
+            from typing import Dict
+            def func() -> None:
+                thing: Dict[str, str] = {}
+
+            # suggested fix
+            from typing import Dict
+            def func() -> None:
+                thing: dict[str, str] = {}
+
 .. class:: UseClsInClassmethod
 
     Enforces using ``cls`` as the first argument in a ``@classmethod``.

pyproject.toml

@@ -78,7 +78,7 @@ target-version = ["py38"]
 
 [tool.fixit]
 enable = ["fixit.rules"]
-python-version = "3.10"
+python-version = "3.8"
 formatter = "ufmt"
 
 [[tool.fixit.overrides]]

src/fixit/rules/use_builtin_types.py

@@ -0,0 +1,124 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from typing import Set
+
+import libcst
+from libcst.metadata import QualifiedNameProvider, ScopeProvider
+
+from fixit import Invalid, LintRule, Valid
+
+
+REPLACE_TYPING_TYPE_ANNOTATION: str = (
+    "You are using typing.{typing_type} as a type annotation "
+    + "but you should use {correct_type} instead."
+)
+
+TYPING_TYPE_TO_REPLACE: Set[str] = {"Dict", "List", "Set", "Tuple", "Type"}
+QUALIFIED_TYPES_TO_REPLACE: Set[str] = {f"typing.{s}" for s in TYPING_TYPE_TO_REPLACE}
+
+
+class UseBuiltinTypes(LintRule):
+    """
+    Enforces the use of builtin types instead of their aliases from the ``typing``
+    module in Python 3.10 and later.
+    """
+
+    PYTHON_VERSION = ">= 3.10"
+
+    METADATA_DEPENDENCIES = (
+        QualifiedNameProvider,
+        ScopeProvider,
+    )
+    VALID = [
+        Valid(
+            """
+            def fuction(list: list[str]) -> None:
+                pass
+            """
+        ),
+        Valid(
+            """
+            def function() -> None:
+                thing: dict[str, str] = {}
+            """
+        ),
+        Valid(
+            """
+            def function() -> None:
+                thing: tuple[str]
+            """
+        ),
+    ]
+    INVALID = [
+        Invalid(
+            """
+            from typing import List
+            def whatever(list: List[str]) -> None:
+                pass
+            """,
+            expected_replacement="""
+            from typing import List
+            def whatever(list: list[str]) -> None:
+                pass
+            """,
+        ),
+        Invalid(
+            """
+            from typing import Dict
+            def func() -> None:
+                thing: Dict[str, str] = {}
+            """,
+            expected_replacement="""
+            from typing import Dict
+            def func() -> None:
+                thing: dict[str, str] = {}
+            """,
+        ),
+        Invalid(
+            """
+            from typing import Tuple
+            def func() -> None:
+                thing: Tuple[str]
+            """,
+            expected_replacement="""
+            from typing import Tuple
+            def func() -> None:
+                thing: tuple[str]
+            """,
+        ),
+    ]
+
+    def __init__(self) -> None:
+        super().__init__()
+        self.annotation_counter: int = 0
+
+    def visit_Annotation(self, node: libcst.Annotation) -> None:
+        self.annotation_counter += 1
+
+    def leave_Annotation(self, original_node: libcst.Annotation) -> None:
+        self.annotation_counter -= 1
+
+    def visit_Name(self, node: libcst.Name) -> None:
+        qualified_names = self.get_metadata(QualifiedNameProvider, node, set())
+
+        is_typing_type = node.value in TYPING_TYPE_TO_REPLACE and all(
+            qualified_name.name in QUALIFIED_TYPES_TO_REPLACE
+            for qualified_name in qualified_names
+        )
+
+        if self.annotation_counter > 0 and is_typing_type:
+            correct_type = node.value.title().lower()
+            scope = self.get_metadata(ScopeProvider, node)
+            replacement = None
+            if scope is not None and correct_type in scope:
+                replacement = node.with_changes(value=correct_type)
+            self.report(
+                node,
+                REPLACE_TYPING_TYPE_ANNOTATION.format(
+                    typing_type=node.value, correct_type=correct_type
+                ),
+                replacement=replacement,
+            )