Fix crash in typecheck checker when metaclass argument is a non-class (#11074)

Signed-off-by: Sai Asish Y <say.apm35@gmail.com>

Author: Sai Asish Y

doc/whatsnew/fragments/11071.bugfix

@@ -0,0 +1,4 @@
+Fix a crash in the typecheck checker when a class uses a non-class object
+(for example a function) as its ``metaclass=`` argument.
+
+Closes #11071

pylint/checkers/typecheck.py

@@ -670,7 +670,7 @@ def _determine_callable(
 
             # Try to use the metaclass' __call__ if any.
             meta = callable_obj.metaclass()
-            if meta and isinstance(meta, nodes.NodeNG):
+            if isinstance(meta, nodes.ClassDef):
                 meta_call, _, from_builtins = _get_local_callable(meta, "__call__")
                 if meta_call and not from_builtins:
                     _check_is_function_def(meta_call)

tests/functional/r/regression_03/regression_11071.py

@@ -0,0 +1,19 @@
+"""Regression test for https://github.com/pylint-dev/pylint/issues/11071.
+
+A class whose ``metaclass=`` argument resolves to a plain ``FunctionDef``
+(rather than a ``ClassDef``) crashed the typecheck checker when looking up
+``__call__`` on the metaclass via ``local_attr``.
+"""
+
+# pylint: disable=missing-docstring,too-few-public-methods,invalid-metaclass
+
+
+def fn():
+    pass
+
+
+class C(metaclass=fn):
+    pass
+
+
+C()