[no-member] Add a regression test for a false positive (#7095)

Closes #3803

Author: Pierre-Sassoulas

tests/functional/n/no/no_member.py

@@ -29,3 +29,16 @@ def peer_joined(self, peer):
     sorted(parse.parse_qsl(parsed_url.query), key=lambda param: param[0]))
 new_parsed_url = parse.ParseResult._replace(parsed_url, query=sorted_query)
 new_url = new_parsed_url.geturl()  # No error here
+
+
+# Regression test for https://github.com/PyCQA/pylint/issues/3803
+# pylint: disable=too-few-public-methods
+class Base:
+    label: str
+
+
+class Derived(Base):
+    label = "I exist!"
+
+
+print(Derived.label)