unsafe_op_in_unsafe_fn warning in Rust edition 2024

[jmjoy]

The unsafe_op_in_unsafe_fn lint now warns by default. This warning detects calls to unsafe operations in unsafe functions without an explicit unsafe block.

warning[E0133]: dereference of raw pointer is unsafe and requires unsafe block
  --> /origin/home/jmjoy/workspace/rust/phper/target/debug/build/phper-sys-ef5a7a32f49c54c5/out/php_bindings.rs:39:20
   |
39 |         let byte = *(core::ptr::addr_of!((*this).storage) as *const u8).offset(byte_index as isize);
   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ dereference of raw pointer
   |
   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/unsafe-op-in-unsafe-fn.html>
   = note: raw pointers may be null, dangling or unaligned; they can violate aliasing rules and cause data races: all of these are undefined behavior
note: an unsafe function restricts its caller, but its body is safe by default
  --> /origin/home/jmjoy/workspace/rust/phper/target/debug/build/phper-sys-ef5a7a32f49c54c5/out/php_bindings.rs:36:5
   |
36 |     pub unsafe fn raw_get_bit(this: *const Self, index: usize) -> bool {
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   = note: `#[warn(unsafe_op_in_unsafe_fn)]` on by default

[jinghao-jia]

Unsafe bitfield raw getters and setters (line 39 in your case) are addressed in https://github.com/rust-lang/rust-bindgen/pull/3124. For other cases, bindgen's --wrap-unsafe-ops option should do the work.

[OmriSteiner]

Maybe it makes sense to enable wrap_unsafe_ops by default? Looks like it was first implemented by #2266 but then it broke building for Rust <1.65, so it was re-implemented as an optional flag.

[jinghao-jia]

Maybe it makes sense to enable wrap_unsafe_ops by default? Looks like it was first implemented by #2266 but then it broke building for Rust <1.65, so it was re-implemented as an optional flag.

Yeah it makes sense to at least enable wrap_unsafe_ops when the target edition is set to 2024.

[barries]

An example of the warnings; would seem to motivate setting .wrap_unsafe_ops(true) by default to reduce DevX friction.

It would also reduce friction to add an #![allow(dead_code)] to the codegenned file, those splatter the error output as well...

impl VersionRange {                                                                                                                             
   #[inline]                                                                                                                                   
    pub unsafe fn Deserialize(&mut self) -> VersionRange {                                                                                      
    │                                                    └──── E0133: consider wrapping the function body in an unsafe block: `{ unsafe `, `}`  
    └──── E0133: an unsafe function restricts its caller, but its body is safe by default                                                       
        VersionRange_Deserialize(self)                                                                                                          
        └──── E0133: call to unsafe function `aa::adp::fw_integration_tests::cpp::VersionRange_Deserialize` is unsafe and requires unsafe block 
              for more information, see <https://doc.rust-lang.org/edition-guide/rust-2024/unsafe-op-in-unsafe-fn.html>                         
              consult the function's documentation for information on how to avoid undefined behavior                                           
              `#[warn(unsafe_op_in_unsafe_fn)]` on by default                                                                                   
        └──── unsafe_op_in_unsafe_fn: call to unsafe function is unsafe and requires an unsafe function or block                                
    }                                                                                                                                           
}