From 0a309bf7d487d92612ecd213686dc5500833f27d Mon Sep 17 00:00:00 2001
From: naglis <827324+naglis@users.noreply.github.com>
Date: Mon, 19 Feb 2024 13:45:05 +0200
Subject: [PATCH] Detect list being mutated by `del` statement

Avoid `use-tuple-over-list` false positives when a list is being mutated
by a `del` statement.
---
 perflint/list_checker.py   |  2 +-
 tests/test_list_checker.py | 22 +++++++++++++++++++++-
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/perflint/list_checker.py b/perflint/list_checker.py
index 068f225..a4dcb60 100644
--- a/perflint/list_checker.py
+++ b/perflint/list_checker.py
@@ -73,7 +73,7 @@ def _mark_mutated(self, _name: nodes.Name):
             del self._lists_to_watch[0][_name.name]
 
     def visit_subscript(self, node: nodes.Subscript):
-        if not isinstance(node.parent, nodes.Assign):
+        if not isinstance(node.parent, (nodes.Assign, nodes.Delete)):
             return
         if not isinstance(node.value, nodes.Name):
             return
diff --git a/tests/test_list_checker.py b/tests/test_list_checker.py
index 0835f46..d50deb6 100644
--- a/tests/test_list_checker.py
+++ b/tests/test_list_checker.py
@@ -45,6 +45,16 @@ def test(): #@
         with self.assertNoMessages():
             self.walk(test_func)
 
+    def test_mutated_list_by_del(self):
+        test_func = astroid.extract_node("""
+        def test():
+            items = [1,2,3,4]
+            del items[0]
+        """)
+
+        with self.assertNoMessages():
+            self.walk(test_func)
+
     def test_mutated_global_list_by_index(self):
         test_func = astroid.extract_node("""
         items = [1,2,3,4]
@@ -63,4 +73,14 @@ def test(): #@
         """)
 
         with self.assertNoMessages():
-            self.walk(test_func)
\ No newline at end of file
+            self.walk(test_func)
+
+    def test_mutated_global_list_by_del(self):
+        test_func = astroid.extract_node("""
+        items = [1,2,3,4]
+        def test():
+            del items[0]
+        """)
+
+        with self.assertNoMessages():
+            self.walk(test_func)