unsafe code warn causes: "implementation of an unsafe trait"

[konstin]

Bug Description

When trying to update to pyo3 0.22 in astral-sh/uv#5590, i get the errors implementation of an unsafe trait and usage of an unsafe block, even though i don't use any unsafe in my code.

pyo3 should place appropriate annotations on generated code

Steps to Reproduce

[package]
name = "pyo3-unsafe"
version = "0.1.0"
edition = "2021"

[lints.rust]
unsafe_code = "warn"

[dependencies]
pyo3 = { version = "0.22.2", features = ["extension-module", "abi3-py37"] }

use std::hash::Hash;

use pyo3::pyclass;

#[derive(Eq, Ord, PartialEq, PartialOrd, Clone)]
#[pyclass(get_all)]
pub struct VersionSpecifier {
    pub(crate) operator: Operator,
    pub(crate) version: Version,
}

#[derive(Eq, Ord, PartialEq, PartialOrd, Debug, Hash, Clone, Copy)]
#[pyo3::pyclass(eq, eq_int)]
pub enum Operator {
    Equal,
}

#[derive(Clone, Eq, PartialEq, PartialOrd, Ord)]
#[pyclass]
pub struct Version;

cargo check:

warning: implementation of an `unsafe` trait
 --> src/lib.rs:8:26
  |
8 |     pub(crate) operator: Operator,
  |                          ^^^^^^^^
  |
  = note: requested on the command line with `-W unsafe-code`

warning: usage of an `unsafe` block
 --> src/lib.rs:8:26
  |
8 |     pub(crate) operator: Operator,
  |                          ^^^^^^^^

warning: implementation of an `unsafe` trait
 --> src/lib.rs:9:25
  |
9 |     pub(crate) version: Version,
  |                         ^^^^^^^

warning: usage of an `unsafe` block
 --> src/lib.rs:9:25
  |
9 |     pub(crate) version: Version,
  |                         ^^^^^^^

warning: 4 warnings emitted

Backtrace

No response

Your operating system and version

Ubuntu 24.04

Your Python version (python --version)

Python 3.12.3

Your Rust version (rustc --version)

rustc 1.80.0 (051478957 2024-07-21)

Your PyO3 version

0.22

How did you install python? Did you use a virtualenv?

pyenv opt build

Additional Info

No response

[LilyFoote]

I can replicate this. Looking into a fix.