Error detected by test is rendered as json format

[tiif]

Problem

When running tests in tests/pass-dep/shims/libc-misc.rs, the error message produced by the test is displayed in json format.

Reproduce:

1. Add an error in tests/pass-dep/shims/libc-misc.rs, I added unused imports below:

    use std::ffi::CString;

2. Run ./miri run --dep tests/pass-dep/shims/libc-misc.rs -Zmiri-disable-isolation
3. The error (i.e. last line of the output) is rendered as json format:

$ rustfmt +miri --edition=2021 --config-path /home/byt/Documents/miri/rustfmt.toml --unstable-features --skip-children ...
$ cargo +miri clippy --manifest-path /home/byt/Documents/miri/Cargo.toml --all-targets
    Finished `dev` profile [optimized + debuginfo] target(s) in 0.07s
$ cargo +miri clippy --manifest-path /home/byt/Documents/miri/cargo-miri/Cargo.toml --all-targets
    Finished `dev` profile [optimized + debuginfo] target(s) in 0.02s
$ cargo +miri clippy --manifest-path /home/byt/Documents/miri/miri-script/Cargo.toml --all-targets
    Finished `dev` profile [optimized + debuginfo] target(s) in 0.01s
{"$message_type":"diagnostic","message":"unused import: `CString`","code":{"code":"unused_imports","explanation":null},"level":"warning","spans":[{"file_name":"tests/pass-dep/shims/libc-misc.rs","byte_start":6845,"byte_end":6852,"line_start":218,"line_end":218,"column_start":26,"column_end":33,"is_primary":true,"text":[{"text":"    use std::ffi::{CStr, CString};","highlight_start":26,"highlight_end":33}],"label":null,"suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"`#[warn(unused_imports)]` on by default","code":null,"level":"note","spans":[],"children":[],"rendered":null},{"message":"remove the unused import","code":null,"level":"help","spans":[{"file_name":"tests/pass-dep/shims/libc-misc.rs","byte_start":6843,"byte_end":6852,"line_start":218,"line_end":218,"column_start":24,"column_end":33,"is_primary":true,"text":[{"text":"    use std::ffi::{CStr, CString};","highlight_start":24,"highlight_end":33}],"label":null,"suggested_replacement":"","suggestion_applicability":"MachineApplicable","expansion":null}],"children":[],"rendered":null}],"rendered":"warning: unused import: `CString`\n   --> tests/pass-dep/shims/libc-misc.rs:218:26\n    |\n218 |     use std::ffi::{CStr, CString};\n    |                          ^^^^^^^\n    |\n    = note: `#[warn(unused_imports)]` on by default\n\n"}

Version:

rustc 1.79.0-nightly (23d47dba3 2024-04-06)
binary: rustc
commit-hash: 23d47dba319331d4418827cfbb8c1af283497d3c
commit-date: 2024-04-06
host: x86_64-unknown-linux-gnu
release: 1.79.0-nightly
LLVM version: 18.1.2
os: Ubuntu 22.04.4 LTS [64-bit]

[RalfJung]

This is somehow related to --dep mode, it doesn't happen for "normal" --run.

[tiif]

Thanks for the quick fix!