compiler/middle/lint: Suggest #[expect(dead_code)] instead of #[allow(dead_code)]
#147717
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rustbot
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rustbot has assigned @petrochenkov. Use |
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r? @estebank since we already talked about it :) |
Turbo87
commented
Oct 15, 2025
| "`{flag} {hyphen_case_lint_name}` implied by `{flag} {hyphen_case_flag_val}`" | ||
| )); | ||
| if matches!(orig_level, Level::Warn | Level::Deny) { | ||
| let suggestion = if name == "dead_code" { "expect" } else { "allow" }; |
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I scoped this to only the dead_code suggestion for now. It might make sense to extend it to others in the future too though.
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This is great! I wonder if it would be hard to make this conditional on the |
I don't think rustc has access to that information from cargo. |
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Until now the compiler suggested
when encountering e.g. an unused function in the codebase.
This PR changes the suggestion to
#[expect(dead_code)], which will warn again once the code is being used somewhere. This is helpful because it lets the developer know that the attribute can now be removed again. Without this the codebase will eventually be littered with stray#[allow(dead_code)]attributes that are no longer serving any purpose.This was suggested in https://bsky.app/profile/steveklabnik.com/post/3m2uh7pf6e225 and I agreed strongly enough to take a look and implement it 😆