Add a check on the existence of __qualname__

pydantic/_internal/_model_construction.py

@@ -334,6 +334,7 @@ def inspect_namespace(  # noqa C901
         elif (
             isinstance(value, type)
             and value.__module__ == namespace['__module__']
+            and '__qualname__' in namespace
             and value.__qualname__.startswith(namespace['__qualname__'])
         ):
             # `value` is a nested type defined in this namespace; don't error

tests/test_create_model.py

@@ -601,3 +601,10 @@ class Y:
     )
     Z = create_model('Z', y=(module.Y, ...))
     assert Z(y={'x': {}}).y is not None
+
+
+def test_type_field_in_the_same_module():
+    class A:
+        pass
+
+    create_model('B', a_cls=(type, A))