A common pattern is to use if/else statements for backward compatibility with deprecated methods to provide support between versions before the deprecation was introduced and to provide a fix for after.

One example can be found here: mglaman/phpstan-drupal#461

if (method_exists($this->moduleHandler, 'invokeAllWIth')) {
 // use the new invokeAllWIth method
} else {
 // use legacy getImplementations method
}

The easiest fix is to add // @phpstan-ignore-next-line whenever using backward compatible code. But I was trying to see if it'd be possible to use a node visitor to detect the if/else to set an attribute flag. Which it does seem possible (whether it is right or wrong.)

Would this package accept a check of checking for an attribute to imply a deprecated scope?

$node->getAttribute('inDeprecatedScope', false)

I don't know how other frameworks are handling this kind of bridge, I need to look.