fix eval invocation in typescript--re-search-backward to work with lexical scoping

[Rogach]

Under lexical scoping variable references won't be found when evaluating the expression, resulting in "eval: Symbol’s value as variable is void: regexp" error.

By the way, do we really need the eval here?

[josteink]

Not sure about the need for (eval) myself, but apart from that the change itself looks good to me!

[josteink]

While the change itself looks good, it reflects on something which used to be broken while the build was still “green”.

Would it be possible to add a test-case for this to prevent future regressions?

[Rogach]

Yes, I'll add the test tomorrow (should be easy - just explicitly set lexical-binding to non-nil).

[Rogach]

Hm, no, seems that it's not that easy - you can't change lexical-binding value during execution, it's only changed on per-file basis or globally.

I asked over in emacs irc and one suggestion was "write a temp file with the setting and code and eval it", but that seems way to involved for a simple test.

One alternative is to switch all tests&code to lexical scoping (seems that lexical scoping is the main way forward nowdays).

[josteink]

You could always create a dedicated file for tests in lexical mode. We already have different test files for different specific sub-genres of tests, so this would really not be any different.

If you want to switch all the tests over, feel free! It’s by no means a requirement though.

[josteink]

Also I have fixed the CI so that all the builds are green now, so if you merge in latest changes from master, this PR should be all green as well 🙂

[Rogach]

I've added the test, but it's horrible (I had to re-read and re-evaluate typescript-mode.el to get it to load with lexical-binding enabled). I'm not even sure how I managed to stumble upon the original bug - it seems that lexical-binding can be enabled only from inside the library file. It's possible that it was some regression inside Emacs itself - I'm running builds from git master, and I can't reproduce my original bug under the latest build.

Also I have fixed the CI so that all the builds are green now, so if you merge in latest changes from master, this PR should be all green as well

I rebased the changes on top of latest master, hopefully the CI runs fine =)

[josteink]

Lol. That’s absolutely terrible indeed, but it does the job. It also doubles as a preparation for migrating to lexical mode proper.

Consider it merged! Thanks for the patch!