rust-lang / rust-lang/rustfmt

Module declared inside macro is not checked

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Rust
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Description

When I declare modules like this

#[cfg(unix)]
pub mod stub_hal;

rustfmt will check module, irrespective of condition.

However, when I declare them using cfg-if crate rustfmt doesn't check module.

cfg_if! {
    if #[cfg(unix)] {
        pub mod stub_hal;
    }
}

Is is designed behavior? Or is macro parsing not implemented for now?

That's rustfmt 1.0.1-nightly (be13559 2018-12-10)

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Research direction

Start by reproducing the cfg_if! example from the issue with rustfmt and compare it with the direct #[cfg(unix)] module declaration. Trace how rustfmt handles the module inside the macro, then verify that the intended behavior is defined and that the stub_hal module is checked consistently.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
tooling
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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