Description
Summary
Unless I'm not understanding something here, declare_interior_mutable_const seems to be firing a false-positive for pointers to inner mutable types. I can understand why constant inner-mutables make no sense, but pointers to static inner mutables are a different thing - the pointer is the constant part, not the object itself, and in certain (all?) contexts, the pointer will not change.
Lint Name
declare_interior_mutable_const
Reproducer
I tried this code:
#![feature(const_refs_to_static)]
#![allow(dead_code)]
use std::mem::MaybeUninit;
use std::sync::Mutex;
static SOME_THING: MaybeUninit<Mutex<usize>> = MaybeUninit::uninit();
const SOME_THING_PTR: *const Mutex<usize> = SOME_THING.as_ptr();I saw this happen:
warning: a `const` item should not be interior mutable
--> src/lib.rs:8:1
|
8 | const SOME_THING_PTR: *const Mutex<usize> = SOME_THING.as_ptr();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: consider making this `Sync` so that it can go in a static item or using a `thread_local`
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#declare_interior_mutable_const
= note: `#[warn(clippy::declare_interior_mutable_const)]` on by default
I expected to see this happen:
No warning.
Playground link:
Version
rustc 1.81.0-nightly (fcc325f1b 2024-07-17)
binary: rustc
commit-hash: fcc325f1bc477975e2ce5ba534fe4c77ff8a8536
commit-date: 2024-07-17
host: x86_64-unknown-linux-gnu
release: 1.81.0-nightly
LLVM version: 18.1.7
Additional Labels
No response