Clippy lints / Pedantic
Clippy lint · Pedantic · checked with Clippy 0.1.99
clippy::pub_underscore_fields: Checks whether any field of the struct is prefixed with an _ (underscore) and also marked pub (public)
What it meansChecks whether any field of the struct is prefixed with an _ (underscore) and also marked pub (public) It is in the pedantic group and off by default.
Does it matter?
Fields prefixed with an _ are inferred as unused, which suggests it should not be marked as pub, because marking it as pub infers it will be used.
Stricter lints with some false positives. Off by default; opt in with clippy::pedantic.
How to fix it
Clippy does not fix this one automatically. Change the code by hand:
Flagged
struct FileHandle {
pub _descriptor: usize,
}
Write this instead
struct FileHandle {
_descriptor: usize,
}
Turn it off, or on
It is off by default. To use it, set it to warn or deny:
Whole crate (Cargo.toml)
[lints.clippy]
pub_underscore_fields = "warn"In code
#![warn(clippy::pub_underscore_fields)]One run
cargo clippy -- -W clippy::pub-underscore-fieldsThe [lints] table needs Rust 1.74 or newer. In a workspace, put it under [workspace.lints.clippy] and add [lints] workspace = true to each member.
Settings in clippy.toml
pub-underscore-fields-behavior: Lint “public” fields in a struct that are prefixed with an underscore based on their exported visibility, or whether they are marked as “pub”.
Clippy's own documentation
What it does
Checks whether any field of the struct is prefixed with an _ (underscore) and also marked
pub (public)
Why is this bad?
Fields prefixed with an _ are inferred as unused, which suggests it should not be marked
as pub, because marking it as pub infers it will be used.
Example
struct FileHandle {
pub _descriptor: usize,
}
Use instead:
struct FileHandle {
_descriptor: usize,
}
OR
struct FileHandle {
pub descriptor: usize,
}
Configuration
-
pub-underscore-fields-behavior: Lint “public” fields in a struct that are prefixed with an underscore based on their exported visibility, or whether they are marked as “pub”.(default:
"PubliclyExported")
From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.
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All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
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