From https://www.drupal.org/project/drupalmoduleupgrader

This project is a command-line script that scans the source of a Drupal 7 module, flags any code that requires updating to Drupal 8, points off to any relevant API change notices, and (where possible) will actually attempt to convert the Drupal 7 code automatically to the Drupal 8 version! The goal is to hit the most widely-used Drupal hooks and ensure there's coverage for them.

That's pretty cool. How hard would it be to have something like that for MediaWiki?

Granted, Drupal has large updates every three years or so while MediaWiki twice a year, so it's somewhat of a moving target, but checking hook signatures (or in general changed method signatures via Phan) should not be hard.