Fixed a false positive for ``unused-variable`` and ``nonlocal`` assignments

When looking for nonlocal names and assignments in upper scope, also look
for AnnAssign nodes.

Close #2671

3 files changed, 20 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index 09d82e474..a7c2794b4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -7,6 +7,10 @@ What's New in Pylint 2.3.0?
 
 Release date: TBA
 
+* Fixed a false positive for ``unused-variable`` and ``nonlocal`` assignments
+
+  Close #2671
+
 * Added ``load_configuration()`` hook for plugins
 
   New optional hook for plugins is added: ``load_configuration()``.
diff --git a/pylint/checkers/variables.py b/pylint/checkers/variables.py
index 5a39f036d..3e487d309 100644
--- a/pylint/checkers/variables.py
+++ b/pylint/checkers/variables.py
@@ -957,7 +957,9 @@ class VariablesChecker(BaseChecker):
                 "unused-argument", args=name, node=stmt, confidence=confidence
             )
         else:
-            if stmt.parent and isinstance(stmt.parent, astroid.Assign):
+            if stmt.parent and isinstance(
+                stmt.parent, (astroid.Assign, astroid.AnnAssign)
+            ):
                 if name in nonlocal_names:
                     return
 
diff --git a/pylint/test/functional/unused_variable.py b/pylint/test/functional/unused_variable.py
index 4e6d58fe4..cbf18fb8e 100644
--- a/pylint/test/functional/unused_variable.py
+++ b/pylint/test/functional/unused_variable.py
@@ -53,3 +53,16 @@ def locals_does_not_account_for_subscopes():
 def unused_import_from():
     from functools import wraps as abc # [unused-import]
     from collections import namedtuple # [unused-import]
+
+
+def function():
+    ann: int = 0
+    assign = 0
+
+    def inner():
+        nonlocal ann, assign
+        ann += 1
+        assign += 1
+        return ann + assign
+
+    return inner()