Summary

unsafe fields (still unstable, see rust-lang/rust#132922) cannot (currently) derive Clone.

(Feel free to close if this should wait until rust-lang/rust#132922 is closer to being stabilized).

Lint Name

expl_impl_clone_on_copy

Reproducer

I tried this code:

#![feature(unsafe_fields)]
#![allow(incomplete_features)]
#![warn(clippy::pedantic)]

pub struct Valid {
    pub unsafe actual: (),
}

unsafe impl Copy for Valid {}

impl Clone for Valid {
    #[inline]
    fn clone(&self) -> Self {
        *self
    }
}

I saw this happen:

warning: you are implementing `Clone` explicitly on a `Copy` type

I expected to see this happen: No warnings, since attempting to derive Clone produces a compiler error.

Version

rustc 1.88.0-nightly (17ffbc81a 2025-04-04)
binary: rustc
commit-hash: 17ffbc81a30c094193836a5d7f90dff273b5df93
commit-date: 2025-04-04
host: aarch64-apple-darwin
release: 1.88.0-nightly
LLVM version: 20.1.2

Additional Labels

No response