Why Cargo Check Is So Slow (eveeifyeve.pages.dev)

What you linked to is a 404.

You're linking to https://eveeifyeve.pages.dev/http://localhost:4321/blogs/car...

You meant to link to https://eveeifyeve.pages.dev/blogs/cargo-check-slow.mdx/

Also, ew, auto-playing music.

Feature request: Rust proc macros and compile time statistics need to be called out on crates.io

We're starting to ban them from our Rust monorepo.

I wonder why procmacros are slow. Can the compiler interpret them or does it have to go to all the work of compiling them before they can run?

#![forbid(proc_macros)]

Is this complaint only about initial checks? Or also checks after a small change?

Neat.

I use bacon with cargo-make to toggle between check, nextest+doctest, and a full series of pre-commit checks.

I'm confused about a couple things:

* What is metadata_decode_entry_impl_trait_header and what does it have to do with proc macros? I suppose if a proc macro emitted code that used impl Trait a bunch then it might need to use this code, but I don't see why that would disproportionately affect compile times.

* What's the proposal for how to fix this?