Clippy lint · Pedantic · checked with Clippy 0.1.99

clippy::borrow_as_ptr: borrow as raw pointer

What it meansChecks for the usage of &expr as *const T or &mut expr as *mut T, and suggest using &raw const or &raw mut instead. It is in the pedantic group and off by default.

What you see

warning: borrow as raw pointer
 --> main.rs:4:9
  |
4 | let p = &val as *const i32;
  |         ^^^^^^^^^^^^^^^^^^ help: try: `&raw const val`
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#borrow_as_ptr
  = note: `-W clippy::borrow-as-ptr` implied by `-W clippy::pedantic`

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?

This would improve readability and avoid creating a reference that points to an uninitialized value or unaligned place. Read the &raw explanation in the Reference for more information.

Stricter lints with some false positives. Off by default; opt in with clippy::pedantic.

How to fix it

Clippy can fix this one for you: run cargo clippy --fix (add --allow-dirty if you have uncommitted changes). Review the diff before you commit.

Flagged

let val = 1;
let p = &val as *const i32;

let mut val_mut = 1;
let p_mut = &mut val_mut as *mut i32;

Write this instead

let val = 1;
let p = &raw const val;

let mut val_mut = 1;
let p_mut = &raw mut val_mut;

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]
borrow_as_ptr = "warn"

In code

#![warn(clippy::borrow_as_ptr)]

One run

cargo clippy -- -W clippy::borrow-as-ptr

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

msrv: The minimum rust version that the project supports. Defaults to the rust-version field in Cargo.toml

Pedanticgroup

allowdefault level

yesfixed by cargo clippy --fix

1.60.0added in Rust

Clippy's own documentation

What it does

Checks for the usage of &expr as *const T or &mut expr as *mut T, and suggest using &raw const or &raw mut instead.

Why is this bad?

This would improve readability and avoid creating a reference that points to an uninitialized value or unaligned place. Read the &raw explanation in the Reference for more information.

Example

let val = 1;
let p = &val as *const i32;

let mut val_mut = 1;
let p_mut = &mut val_mut as *mut i32;

Use instead:

let val = 1;
let p = &raw const val;

let mut val_mut = 1;
let p_mut = &raw mut val_mut;

Configuration

msrv: The minimum rust version that the project supports. Defaults to the rust-version field in Cargo.toml

(default: current version)

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

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