Status updates
Week 1

I'm going to provide a weekly update for the status of stc (opens in a new tab). This is the first post.



    required_error: 5155 => 4463,
    matched_error: 4711 => 5421,
    extra_error: 1983 => 999,
    panic: 103 => 89,

This is the diff for the last commit on November, 6 (opens in a new tab) and the last commit on November, 13 (opens in a new tab)


Many people contributed to stc, either by contributing developer time or financially.


This is a screenshot for 1 month because this is the first update.

Noticeable changes

This improve performance by margin. Type of stc has some invariants to make it easier to handle. One example of the invariants is that a union cannot include a union as an element, because it causes lots of troubles with the pattern matching of Rust. There's a function named fix, which ensures that a type satisfies all of the invariants. But previously, it was recursive and it was a costly operation. It's now shallow and it does not recurse into Union nor Intersection. Performance gain is noticeable. The test execution with a xdebug build previously took 1m 45s, but it now takes 1m 20s.

My plan is to provide a LSP for TypeScript after fixing all type inference bugs. I want to make it testable, so I tried various structures. While triage, I found a project structure which is testable. I decided to use the examples directory of cargo to create a LSP binary which can be used for testing. Basically, this structure allows using exactly same code for testing environment and the release build of stc LSP.

Special thanks to Deno because I referred to the structure of Deno lsp a lot.

This is one of the tasks I wanted to do, but postponed due to the time. Divy helped a lot, and I managed to update swc crates. This introduced some regressions, but those are all fixed at the moment.

This patch fixes the issue which blocked people from trying stc on their own project. stc could verify a huge TypeScript module if it does not have an import, but this patch reduces the restrictions for real-world project further.