| Instantiating and using a contextmanager inside a generator function can |
| result in unexpected behavior if there is an expectation that the context is only |
| available for the generator function. In the case that the generator is not closed or destroyed |
| then the context manager is held suspended as is. |
| |
| This message warns on the generator function instead of the contextmanager function |
| because the ways to use a contextmanager are many. |
| A contextmanager can be used as a decorator (which immediately has ``__enter__``/``__exit__`` applied) |
| and the use of ``as ...`` or discard of the return value also implies whether the context needs cleanup or not. |
| So for this message, warning the invoker of the contextmanager is important. |
