Modules are obviously not executable, but should not lead to traceback when executed

jedi/plugins/stdlib.py

@@ -108,7 +108,7 @@ class StdlibPlugin(BasePlugin):
             else:
                 if context.parent_context == self._evaluator.builtins_module:
                     module_name = 'builtins'
-                elif context.parent_context.is_module():
+                elif context.parent_context is not None and context.parent_context.is_module():
                     module_name = context.parent_context.name.string_name
                 else:
                     return callback(context, arguments=arguments)

test/completion/basic.py

@@ -295,6 +295,11 @@ __file__
 #? ['__file__']
 __file__
 
+#? str()
+math.__file__
+# Should not lead to errors
+#?
+math()
 
 # -----------------
 # with statements