~[ ] I have added tests to demonstrate the contribution is correctly implemented: this usually includes both positive and negative tests, showing the happy path(s) and featuring intentionally broken cases~ I didn't add tests, just checked it works locally and it should be observable in CI in this check's error message. To properly test everything we should fix issue #315
[x] I have run all the tests locally and no test failure was reported
[x] I have run the linter, formatter and spellchecker
[x] I did not do unrelated and/or undiscussed refactorings -- had to rename some errors because of introducing a parse error category
Closes #406