Recent changes appear to generate new warnings for the improper_ctypes lint. Code such as this:
struct Internals {
// ...
}
#[repr(C)]
pub struct internals_t {
internals: Internals,
}
pub extern "C" fn internals_new() -> *mut internals_t {
loop {}
}now generates the warning:
warning: `extern` fn uses type `Internals`, which is not FFI-safe
--> src/lib.rs:10:38
|
10 | pub extern "C" fn internals_new() -> *mut internals_t {
| ^^^^^^^^^^^^^^^^ not FFI-safe
|
= note: `#[warn(improper_ctypes)]` on by default
= help: consider adding a `#[repr(C)]` or `#[repr(transparent)]` attribute to this struct
= note: this struct has unspecified layout
note: type defined here
--> src/lib.rs:1:1
|
1 | / struct Internals {
2 | |
3 | | }
| |_^
This pattern can be quite common if a Rust library is exposing a C interface. Many pointer types moving across the boundary are intentionally opaque to the C side of the interface, so there's no need for #[repr(C)]
The lint, however, now generates thousands of warnings on these crates and has to basically be shut off entirely, removing the usefulness of the lint in the first place.
Recent changes appear to generate new warnings for the
improper_ctypeslint. Code such as this:now generates the warning:
This pattern can be quite common if a Rust library is exposing a C interface. Many pointer types moving across the boundary are intentionally opaque to the C side of the interface, so there's no need for
#[repr(C)]The lint, however, now generates thousands of warnings on these crates and has to basically be shut off entirely, removing the usefulness of the lint in the first place.