handle no-member false positive for generators

doc/whatsnew/fragments/2567.bugfix

@@ -0,0 +1,3 @@
+Fixed a false positive case when a generator object received ``no-member`` error.
+
+Closes #2567

pylint/checkers/typecheck.py

@@ -510,6 +510,14 @@ def _emit_no_member(
             return False
         except astroid.NotFoundError:
             pass
+    if isinstance(owner, astroid.bases.Generator) and node.attrname in {
+        "__enter__",
+        "__exit__",
+    }:
+        # Avoid false positive on generators.
+        # See https://github.com/PyCQA/pylint/issues/2567
+        return False
+
     if owner_name and node.attrname.startswith("_" + owner_name):
         # Test if an attribute has been mangled ('private' attribute)
         unmangled_name = node.attrname.split("_" + owner_name)[-1]

tests/functional/n/no/no_member_generators.py

@@ -0,0 +1,15 @@
+"""Test no-member for generators
+"""
+# pylint: disable=missing-docstring, too-few-public-methods
+import contextlib
+
+@contextlib.contextmanager
+def context_manager():
+    try:
+        yield
+    finally:
+        pass
+
+cm = context_manager()
+cm.__enter__()
+cm.__exit__(None, None, None)