Install Rector and apply ClassPropertyAssignToConstructorPromotionRector

[gnutix]

Hello there! I've noticed that the project was not using promoted properties, even though its minimum PHP version supports them. Yet it's using readonly properties already. So I thought it would be a good idea to add Rector in the project to allow doing automated refactorings to keep the codebase up-to-date.

With the current config file, if you bump the minimum PHP version in composer.json, it will apply the refactorings that can be done in the new PHP version, making sure the code is always the latest and brightest.

cf. https://getrector.com/documentation/integration-to-new-project

Let me know what you think.

TODO

• [x] Install Rector in tools/ (to be run with tools/rector/vendor/bin/rector process -c tools/rector/rector.php)
• [x] PHP 5.3 - 5.6 (nothing changed)
• [x] PHP 7.0 - 7.4 (nothing changed)
• [x] PHP 8.0 :
  • [x] ClassPropertyAssignToConstructorPromotionRector applied (I made my best to keep the most complete comments around)
• [x] PHP 8.1 (nothing changed)
• [x] Add type coverage at maximum level
• [x] Add dead code at maximum level
  • [x] ~SimplifyUselessVariableRector~ skipped
• [x] ECS: apply TrailingCommaInMultilineFixer for everything

[gnutix]

Coverage decreased (-0.01%) to 99.363%

@BenMorel This PR is ready to be reviewed, the failed CI is not a problem.

[gnutix]

I think we're all good here. Would you mind creating a release once this PR is merged (and maybe #98 I guess) ? :pray:

[BenMorel]

Thank you, @gnutix!

[BenMorel]

@gnutix Released in 0.6.1!