regression: error: module should be marked with the #[cfg(test)] attribute

@rustbot

https://crater-reports.s3.amazonaws.com/beta-1.87-3/beta-2025-04-20/gh/greged93.cleanup/log.txt

[INFO] [stdout] error: module should be marked with the `#[cfg(test)]` attribute
[INFO] [stdout]        
[INFO] [stdout]          = help: add `#[cfg(test)]` to the module
[INFO] [stdout]        
[INFO] [stdout]   --> crates/after-test_test/src/lib.rs:3:1
[INFO] [stdout]    |
[INFO] [stdout] 3  | / mod panics {
[INFO] [stdout] 4  | |     fn panic_with_message() {
[INFO] [stdout] 5  | |         panic!("This is a panic message");
[INFO] [stdout] ...  |
[INFO] [stdout] 10 | |     fn test_should_panic() {}
[INFO] [stdout] 11 | | }
[INFO] [stdout]    | |_^

(and several more like that)

That particular error message comes from their own proc-macro. The module does have the expected attribute, but I suppose something must have changed in how we provide that to the macro.

#[after_test::cleanup(panic_with_message)]
#[cfg(test)]
mod panics {
    fn panic_with_message() {
        panic!("This is a panic message");
    }

    #[test]
    #[should_panic(expected = "This is a panic message")]
    fn test_should_panic() {}
}

Version it worked on

It most recently worked on: 1.86.0

Version with regression

rustc 1.87.0-beta.5 (386abeb93 2025-04-19) in crater #139827.

@rustbot modify labels: +regression-from-stable-to-beta -regression-untriaged

cargo test with the following reduced macro:

use proc_macro::TokenStream;

#[proc_macro_attribute]
pub fn cleanup(_: TokenStream, item: TokenStream) -> TokenStream {
    dbg!(&item);
    TokenStream::new()
}

and usage

#[y::cleanup]
#[cfg(test)]
mod panics {}

beta is indeed just printing

[src/lib.rs:5:5] &item = TokenStream [
    Ident {
        ident: "mod",
        span: #0 bytes(41..44),
    },
    Ident {
        ident: "panics",
        span: #0 bytes(45..51),
    },
    Group {
        delimiter: Brace,
        stream: TokenStream [],
        span: #0 bytes(52..54),
    },
]

but stable gets

[src/lib.rs:5:5] &item = TokenStream [
    Punct {
        ch: '#',
        spacing: Alone,
        span: #0 bytes(28..29),
    },
    Group {
        delimiter: Bracket,
        stream: TokenStream [
            Ident {
                ident: "cfg",
                span: #0 bytes(30..33),
            },
            Group {
                delimiter: Parenthesis,
                stream: TokenStream [
                    Ident {
                        ident: "test",
                        span: #0 bytes(34..38),
                    },
                ],
                span: #0 bytes(33..39),
            },
        ],
        span: #0 bytes(29..40),
    },
    Ident {
        ident: "mod",
        span: #0 bytes(41..44),
    },
    Ident {
        ident: "panics",
        span: #0 bytes(45..51),
    },
    Group {
        delimiter: Brace,
        stream: TokenStream [],
        span: #0 bytes(52..54),
    },
]

@rustbot

Regression in rust-lang-ci@8d60e92
The PR introducing the regression in this rollup is #138844: expand: Leave traces when expanding cfg attributes

searched nightlies: from nightly-2025-01-01 to nightly-2025-04-23
regressed nightly: nightly-2025-03-28
searched commit range: a2e6356...3f55023
regressed commit: 3f55023

bisected with cargo-bisect-rustc v0.6.9

Host triple: x86_64-unknown-linux-gnu
Reproduce with:

cargo bisect-rustc --start=2025-01-01 -- test

@rustbot label S-has-mcve S-has-bisection

@petrochenkov

This needs a crater run, because it changes observable behavior (in an intended way) - proc macros can no longer see expanded cfg(true) attributes.

cc @petrochenkov: can you please double-check if this is intended observable behavior change re. #138844.

I also tagged #138844 w/ compat relnotes (#140243) to be safe.

This needs a crater run, because it changes observable behavior (in an intended way) - proc macros can no longer see expanded cfg(true) attributes.

cc @petrochenkov: can you please double-check if this is intended observable behavior change re. #138844.

Yes, this is an intended change.

Closing in favor of compat relnotes (#140243) since this is an intended change.

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regression: error: module should be marked with the `#[cfg(test)]` attribute #140225

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regression: error: module should be marked with the #[cfg(test)] attribute #140225

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cyrgani commented on Apr 23, 2025

cyrgani commented on Apr 23, 2025

jieyouxu commented on Apr 24, 2025

jieyouxu commented on Apr 24, 2025

petrochenkov commented on Apr 24, 2025

jieyouxu commented on May 1, 2025

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regression: error: module should be marked with the `#[cfg(test)]` attribute #140225