Exempt annotated assignments without variable from ``class-variable-s…

…lots-conflict``

Close #3141

ChangeLog

@@ -18,6 +18,10 @@ Release date: TBA
 
    Close #3145
 
+* Exempt annotated assignments without variable from ``class-variable-slots-conflict``
+
+  Close #3141
+
 
 What's New in Pylint 2.4.1?
 ===========================

pylint/checkers/classes.py

@@ -1135,9 +1135,14 @@ def _check_slots_elt(self, elt, node):
                     "invalid-slots-object", args=inferred.as_string(), node=elt
                 )
 
-            # Check if we have a conflict with a class variable
+            # Check if we have a conflict with a class variable.
             class_variable = node.locals.get(inferred.value)
             if class_variable:
+                # Skip annotated assignments which don't conflict at all with slots.
+                if len(class_variable) == 1:
+                    parent = class_variable[0].parent
+                    if isinstance(parent, astroid.AnnAssign) and parent.value is None:
+                        return
                 self.add_message(
                     "class-variable-slots-conflict", args=(inferred.value,), node=elt
                 )

tests/functional/c/class_variable_slots_conflict_exempted.py

@@ -0,0 +1,4 @@
+# pylint: disable=missing-docstring,too-few-public-methods
+class Example:
+    __slots__ = ["field"]
+    field: int