Sometimes, the error shown in Vim (and apparently VS Code too) is printed with ASCII color codes showing in the string from rust_analyzer. It makes the error very hard to read. See neovim/nvim-lspconfig#2760.

It seems to me like rust-analyzer does not properly distinguish between being executed in a terminal environment or not, and decide from that whether to print ASCII color codes or skip them.

In terminal:

In editor:

Steps to reproduce

1. Create the following crate:

cargo new -q foo
cd foo
cargo add -q rocket@0.5.0-rc.3
cat <<EOF > src/main.rs
use rocket::UriDisplayPath;

fn main() {
    println!("Hello, world!");
}

#[derive(UriDisplayPath)]
pub enum Foo {
    Bar,
}
EOF

2. Optionally run cargo check.
3. Open src/main.rs with Vim.

Other info

rust-analyzer version: (eg. output of "rust-analyzer: Show RA Version" command, accessible in VSCode via Ctrl/⌘+Shift+P)

Mason reports rust-analyzer 2023-08-07.

rustc version: (eg. output of rustc -V)

$ rustc -V
rustc 1.71.1 (eb26296b5 2023-08-03)

relevant settings: (eg. client settings, or environment variables like CARGO, RUSTC, RUSTUP_HOME or CARGO_HOME)

Not sure, nothing I've set explicitly at least. I run NeoVim with rust-lang/rust.vim and rust_analyzer for lspconfig installed via Mason.