Could we rename his into serializer, instead of unparser?

Or maybe formatter?

Or stringifier?

I have also wondered about the naming and done a bit of searching. This is an unparser.

As far as I understand the only reason for this is to provide better error messages when change detection throws. If so, should not we just show the source we parsed the AST from?

The main reason why I've created this is to help with parser tests (see #2348).

This can also probably be used in place of ASTWithSource, but not the intent of this PR

I can see how it is useful for tests. Should it be in the tests directory then?

@vsavkin I've moved the UnParser to the test folder in the last commit, PTAL.

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}