[rustc.git] / src / tools / clippy / src / docs / cast_slice_from_raw_parts.txt

### What it does
Checks for a raw slice being cast to a slice pointer

### Why is this bad?
This can result in multiple `&mut` references to the same location when only a pointer is
required.
`ptr::slice_from_raw_parts` is a safe alternative that doesn't require
the same [safety requirements] to be upheld.

### Example
```
let _: *const [u8] = std::slice::from_raw_parts(ptr, len) as *const _;
let _: *mut [u8] = std::slice::from_raw_parts_mut(ptr, len) as *mut _;
```
Use instead:
```
let _: *const [u8] = std::ptr::slice_from_raw_parts(ptr, len);
let _: *mut [u8] = std::ptr::slice_from_raw_parts_mut(ptr, len);
```
[safety requirements]: https://doc.rust-lang.org/std/slice/fn.from_raw_parts.html#safety
Commit	Line	Data
f2b60f7d FG	1	### What it does
	2	Checks for a raw slice being cast to a slice pointer
	3
	4	### Why is this bad?
	5	This can result in multiple `&mut` references to the same location when only a pointer is
	6	required.
	7	`ptr::slice_from_raw_parts` is a safe alternative that doesn't require
	8	the same [safety requirements] to be upheld.
	9
	10	### Example
	11	```
	12	let _: const [u8] = std::slice::from_raw_parts(ptr, len) as const _;
	13	let _: mut [u8] = std::slice::from_raw_parts_mut(ptr, len) as mut _;
	14	```
	15	Use instead:
	16	```
	17	let _: *const [u8] = std::ptr::slice_from_raw_parts(ptr, len);
	18	let _: *mut [u8] = std::ptr::slice_from_raw_parts_mut(ptr, len);
	19	```
	20	[safety requirements]: https://doc.rust-lang.org/std/slice/fn.from_raw_parts.html#safety