Add CodeRange.__contains__

libcst/_position.py

@@ -56,3 +56,14 @@ def __init__(self, start: _CodePositionT, end: _CodePositionT) -> None:
             end = cast(CodePosition, end)
             object.__setattr__(self, "start", start)
             object.__setattr__(self, "end", end)
+
+    def __contains__(self, pos: _CodePositionT, /) -> bool:
+        if isinstance(pos, tuple):
+            line, column = pos
+        else:
+            line, column = pos.line, pos.column
+
+        return (
+            self.start.line <= line <= self.end.line
+            and self.start.column <= column <= self.end.column
+        )

libcst/tests/test_position.py

@@ -0,0 +1,29 @@
+# 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 libcst._position import _CodePositionT, CodePosition, CodeRange
+from libcst.testing.utils import data_provider, UnitTest
+
+
+code_range = CodeRange((1, 2), (4, 5))
+
+
+class PositionTest(UnitTest):
+    @data_provider(
+        [
+            (CodePosition(1, 2), True),
+            ((1, 2), True),
+            (CodePosition(3, 3), True),
+            ((3, 3), True),
+            (CodePosition(2, 1), False),
+            ((2, 1), True),
+            (CodePosition(5, 4), False),
+            ((5, 4), False),
+        ]
+    )
+    def test_code_range_contains(
+        self, position: _CodePositionT, expected: bool
+    ) -> None:
+        self.assertEqual(position in code_range, expected)