How to display errors raised in `Completer` class, in `Validator` bar?

Is there a way to send the exception object that's raised in Completer class, to the Validator class of the same prompt, so that the errors raised during the autocomplete operation can be displayed in the Validator bar as well?

Idk if this is a very niche request. And I hope this doesn't require to do any kind of complex stuff like monkeypatching, etc.

Idk how to resolve this even with a shared context object, because the Validator runs before the Completer class most of the time. And that's not suitable to display the error that's raised in the previous iteration in the next iteration which won't make sense at all.

Start by tracing the Completer and Validator lifecycle for the same prompt, focusing on when each runs and how exceptions are currently handled. The issue does not name files or tests; done would require a documented, non-monkeypatched way to make autocomplete errors available to the Validator bar, with tests covering the timing and displayed error.