Usability: “... INFO ...” prefix on rustc output makes emacs not recognize errors

[dabrahams]

Problem

Developing in emacs, if you issue M-x compile RET dx build and there are rust errors, emacs doesn't pick them up so you can't easily jump to it. That's because the errors are preceded by some stuff emacs doesn't recognize, e.g.:

   2.255s  INFO  error[E0432]: unresolved import `document`
 --> packages/ui/src/application_state.rs:1:5
  |
1 | use document::*;
  |     ^^^^^^^^ help: a similar path exists: `crate::document`
  |
  = note: `use` statements changed in Rust 2018; read more at <https://doc.rust-lang.org/edition-guide/rust-2018/module-system/path-clarity.html>

Steps To Reproduce

Steps to reproduce the behavior:

• introduce a rust error to an existing project
• in emacs, make sure you have rust-mode loaded
• M-x compile dx build RET
• M-x compilation-next-error RET

Expected behavior

Emacs shows me the file where the error is, with the cursor where the error was reported.

Screenshots

Environment:

• Dioxus version: dioxus 0.7.0-rc.0 (a519fba)
• Rust version: rustc 1.89.0 (29483883e 2025-08-04)
• OS info: macOS
• App platform: desktop

[dabrahams]

It's actually almost impossible to work around this problem because of this function. One has to redefine it to account for the timestamp and INFO prefix. Emacs actually appears to hang when the function is used as-is on dioxus output, because it can never find the beginning of the error message.