rust-clippy/tests/ui/cast_alignment.rs

51 lines
1.6 KiB
Rust

//! Test casts for alignment issues
#![feature(rustc_private)]
#![feature(core_intrinsics)]
extern crate libc;
#[warn(clippy::cast_ptr_alignment)]
#[allow(
clippy::no_effect,
clippy::unnecessary_operation,
clippy::cast_lossless,
clippy::borrow_as_ptr
)]
fn main() {
/* These should be warned against */
// cast to more-strictly-aligned type
(&1u8 as *const u8) as *const u16;
(&mut 1u8 as *mut u8) as *mut u16;
// cast to more-strictly-aligned type, but with the `pointer::cast` function.
(&1u8 as *const u8).cast::<u16>();
(&mut 1u8 as *mut u8).cast::<u16>();
/* These should be ok */
// not a pointer type
1u8 as u16;
// cast to less-strictly-aligned type
(&1u16 as *const u16) as *const u8;
(&mut 1u16 as *mut u16) as *mut u8;
// For c_void, we should trust the user. See #2677
(&1u32 as *const u32 as *const std::os::raw::c_void) as *const u32;
(&1u32 as *const u32 as *const libc::c_void) as *const u32;
// For ZST, we should trust the user. See #4256
(&1u32 as *const u32 as *const ()) as *const u32;
// Issue #2881
let mut data = [0u8, 0u8];
unsafe {
let ptr = &data as *const [u8; 2] as *const u8;
let _ = (ptr as *const u16).read_unaligned();
let _ = core::ptr::read_unaligned(ptr as *const u16);
let _ = core::intrinsics::unaligned_volatile_load(ptr as *const u16);
let ptr = &mut data as *mut [u8; 2] as *mut u8;
let _ = (ptr as *mut u16).write_unaligned(0);
let _ = core::ptr::write_unaligned(ptr as *mut u16, 0);
let _ = core::intrinsics::unaligned_volatile_store(ptr as *mut u16, 0);
}
}