DebugClassCloader is already able to turn @return annotations into real return types.

We run it in the CI to ensure that type-declarations are in sync with the behavior of the code.

This can be reproduced locally by running:

composer i -o
SYMFONY_PATCH_TYPE_DECLARATIONS=force=1 php .github/patch-types.php

But this doesn't work on union types:

CodeExtension::getFileLink is one example of a method that should be patched, but isn't right now.

I'm opening this PR to ask for help: this limitation should be removed when PHP 8 is used.

PR welcome :)