Auto-fix is the most dangerous feature a linter has. Every other part of the tool only reads your code. --fix writes to it, usually across a whole repository, usually in CI, usually without anyone reading the diff.
So it is worth asking a blunt question: does the fixer ever produce output the tool itself cannot read back?
There is a cheap way to find out, and the input you need is already sitting in the repository.
The invariant
If a fixture parses cleanly, its fix output must parse cleanly too.
