Improve syntax error locality details for IDE tooling (VSCode/ElixirLS)

[nicnilov]

Elixir and Erlang/OTP versions

Erlang/OTP 27 [erts-15.1.2] [source] [64-bit] [smp:12:12] [ds:12:12:10] [async-threads:1] [jit]

Elixir 1.17.3 (compiled with Erlang/OTP 27)

Operating system

macOS 14.7.4

Current behavior

This is an issue I previously reported to ElixirLS repo (Issue#451) but was advised to move here.

When using VSCode with the ElixirLS extension version 0.26.4, there is a distracting behavior of syntax error highlighting. On pretty much any non-matching do..end block the whole module gets highlighted with squiggles which is quite distracting. As during editing it is not rare to have non-matching do..end blocks, this happens a lot.

As far as I can recall, this is not a very old behavior, and on a previous Elixir or ElixirLS version the whole-module highlighting didn't happen, although I can't tell on which, maybe around Elixir 1.14.

As I understand, the ability of IDE tooling (ElixirLS in particular) to highlight the errors location with better precision is limited by the amount of information Elixir tokenizer / parser / compiler makes available.

Please refer to the linked ElixirLS issue for screenshots and other details, as I'm not certain where this issue should belong in the end.

Expected behavior

In case of a non-matching block delimiters only have the opening one of the deepest affected block selected, and not the whole block, and of course not anything outside.

[josevalim]

Hi @nicnilov, thank you, what do you think about me joining the ElixirLS discussion so we have it consolidated in a single place and then, if necessary, we reopen this one?

[nicnilov]

@josevalim Thanks for a quick reply, please join.

[josevalim]

Closing this but we will reopen if we get specific requirements from downstream. :) The information on the exception is correct today, and that's what we should aim for, how to display that visually it is not our decision to make, but we can add more metadata if necessary!