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Unable to expect the missing_panics_doc and missing_errors_doc lints on main function #14491

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CardboardTurkey opened this issue Mar 28, 2025 · 4 comments · May be fixed by #14505
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Unable to expect the missing_panics_doc and missing_errors_doc lints on main function #14491

CardboardTurkey opened this issue Mar 28, 2025 · 4 comments · May be fixed by #14505
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@longfangsong
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C-bug Category: Clippy is not doing the correct thing

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@CardboardTurkey
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CardboardTurkey commented Mar 28, 2025 •
edited by rustbot
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Summary

My code base denies clippy::missing_panics_doc, clippy::missing_errors_doc and clippy::allow_attributes globally. However I also have a pub main function that doesn't need documentation.

If I use expect to allow the first two on main, clippy complains that the lint is unfulfilled - even though it has stopped complaining about the missing docs.

Everything works fine on functions that aren't main.

Playground: https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=acbdff6f05c01e67eee4ad557ff6e06a

Reproducer

I tried this code:

#![deny(clippy::missing_panics_doc)]
#![deny(clippy::missing_errors_doc)]
#![deny(clippy::allow_attributes)]

use std::env::var;

#[expect(clippy::missing_panics_doc, reason = "main doesn't need docs")]
#[expect(clippy::missing_errors_doc, reason = "main doesn't need docs")]
pub fn main() -> Result<(), &'static str> {
    let val = var("Hello").unwrap();
    match val.as_str() {
        "hello" => Ok(()),
        _ => Err("Oh no"),
    }
}

I expected to see this happen:

No complaints from clippy

Instead, this happened:

Clippy complains about unfulfilled lints

    Checking playground v0.0.1 (/playground)
warning: this lint expectation is unfulfilled
 --> src/main.rs:6:10
  |
6 | #[expect(clippy::missing_panics_doc, reason = "main doesn't need docs")]
  |          ^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: main doesn't need docs
  = note: `#[warn(unfulfilled_lint_expectations)]` on by default

warning: this lint expectation is unfulfilled
 --> src/main.rs:7:10
  |
7 | #[expect(clippy::missing_errors_doc, reason = "main doesn't need docs")]
  |          ^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: main doesn't need docs

warning: `playground` (bin "playground") generated 2 warnings
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.51s

Version

rustc 1.85.1 (4eb161250 2025-03-15)
binary: rustc
commit-hash: 4eb161250e340c8f48f66e2b929ef4a5bed7c181
commit-date: 2025-03-15
host: x86_64-unknown-linux-gnu
release: 1.85.1
LLVM version: 19.1.7

Additional Labels

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@CardboardTurkey CardboardTurkey added the C-bug Category: Clippy is not doing the correct thing label Mar 28, 2025
@CardboardTurkey CardboardTurkey changed the title Unable to expect the missing_panics_doc and missing_errors_doc on main function Unable to expect the missing_panics_doc and missing_errors_doc lints on main function Mar 28, 2025
@longfangsong
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@longfangsong longfangsong linked a pull request Mar 30, 2025 that will close this issue
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@longfangsong
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longfangsong commented Mar 30, 2025 •
edited
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In fact clippy::missing_panics_doc and clippy::missing_errors_doc are not checked on main.

I'm not very sure whether it is something by design (the document does not clarify this) but I opened #14505 anyway. Let's see how the maitainers think about this.

@CardboardTurkey
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@longfangsong Ah you made me realise something. If I remove the expects from the playground example, you're right - clippy doesn't complain about lack of docs on main.

However in my actual codebase I'm not using a main.rs file, but instead a file in src/bin. There it does complain about the lack of docs on main.

@Alexendoo
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Are you including the src/bin file in another context - e.g. if the lint is triggering in src/bin/foo.rs are you making foo a module of the library target or another bin target?

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C-bug Category: Clippy is not doing the correct thing
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fix: enable checking doc attributes on entrypoint function to fix #14491 longfangsong/rust-clippy
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@Alexendoo @longfangsong @CardboardTurkey