Clippy lint · Restriction · checked with Clippy 0.1.99

clippy::absolute_paths: consider bringing this path into scope with the `use` keyword

What it meansChecks for usage of items through absolute paths, like std::f64::consts::PI. It is in the restriction group and off by default.

What you see

warning: consider bringing this path into scope with the `use` keyword
 --> main.rs:3:9
  |
3 | let x = std::f64::consts::PI;
  |         ^^^^^^^^^^^^^^^^^^^^
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#absolute_paths
  = note: requested on the command line with `-W clippy::absolute-paths`

Real output of Clippy 0.1.99 (Rust 1.99) on the example below. Names and line numbers in yours will differ.

Does it matter?

Many codebases have their own style when it comes to importing, but one that is seldom used is using absolute paths everywhere. This is generally considered unidiomatic, and you should add a use statement. The default maximum segments (2) is pretty strict, you may want to increase this in clippy.toml. Note: One exception to this is code from macro expansion - this does not lint such cases, as using absolute paths is the proper way of referencing items in one.

Lints that forbid language features for specific codebases (no unwrap, no indexing...). Off by default; pick them one by one, never the whole group.

How to fix it

Clippy does not fix this one automatically. Change the code by hand:

Flagged

let x = std::f64::consts::PI;

Write this instead

use std::f64;
use std::f64::consts;
use std::f64::consts::PI;
let x = f64::consts::PI;
let x = consts::PI;
let x = PI;
use std::f64::consts as f64_consts;
let x = f64_consts::PI;

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]
absolute_paths = "warn"

In code

#![warn(clippy::absolute_paths)]

One run

cargo clippy -- -W clippy::absolute-paths

The [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

absolute-paths-allowed-crates: Which crates to allow absolute paths from
absolute-paths-max-segments: The maximum number of segments a path can have before being linted, anything above this will be linted.

Restrictiongroup

allowdefault level

nofixed by cargo clippy --fix

1.73.0added in Rust

Clippy's own documentation

What it does

Checks for usage of items through absolute paths, like std::f64::consts::PI.

Why restrict this?

Many codebases have their own style when it comes to importing, but one that is seldom used is using absolute paths everywhere. This is generally considered unidiomatic, and you should add a use statement.

The default maximum segments (2) is pretty strict, you may want to increase this in clippy.toml.

Note: One exception to this is code from macro expansion - this does not lint such cases, as using absolute paths is the proper way of referencing items in one.

Known issues

There are currently a few cases which are not caught by this lint:

Macro calls. e.g. path::to::macro!()
Derive macros. e.g. #[derive(path::to::macro)]
Attribute macros. e.g. #[path::to::macro]

Example

let x = std::f64::consts::PI;

Use any of the below instead, or anything else:

use std::f64;
use std::f64::consts;
use std::f64::consts::PI;
let x = f64::consts::PI;
let x = consts::PI;
let x = PI;
use std::f64::consts as f64_consts;
let x = f64_consts::PI;

Configuration

absolute-paths-allowed-crates: Which crates to allow absolute paths from

(default: [])
absolute-paths-max-segments: The maximum number of segments a path can have before being linted, anything above this will be linted.

(default: 2)

From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.

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