inspect.getfile: Don't crash on classes without '__module__' attribute #20372

Some classes defined in C may not have the '__module__' attribute, so
we now handle this case to avoid having unexepected AttributeError.
diff --git a/Lib/inspect.py b/Lib/inspect.py
index 781a532..3599e02 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -516,9 +516,10 @@
             return object.__file__
         raise TypeError('{!r} is a built-in module'.format(object))
     if isclass(object):
-        object = sys.modules.get(object.__module__)
-        if hasattr(object, '__file__'):
-            return object.__file__
+        if hasattr(object, '__module__'):
+            object = sys.modules.get(object.__module__)
+            if hasattr(object, '__file__'):
+                return object.__file__
         raise TypeError('{!r} is a built-in class'.format(object))
     if ismethod(object):
         object = object.__func__
diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
index 028eeb9..ec04c85 100644
--- a/Lib/test/test_inspect.py
+++ b/Lib/test/test_inspect.py
@@ -319,6 +319,16 @@
     def test_getfile(self):
         self.assertEqual(inspect.getfile(mod.StupidGit), mod.__file__)
 
+    def test_getfile_class_without_module(self):
+        class CM(type):
+            @property
+            def __module__(cls):
+                raise AttributeError
+        class C(metaclass=CM):
+            pass
+        with self.assertRaises(TypeError):
+            inspect.getfile(C)
+
     def test_getmodule_recursion(self):
         from types import ModuleType
         name = '__inspect_dummy'