Open
Description
Using the following flags
--force-warn clippy::as-ptr-cast-mut
this code:
// FIXME: Without retagging, optimization kills finding this problem
// compile-flags: -Zmir-opt-level=0
#![allow(unused_variables)]
mod safe {
use std::slice::from_raw_parts_mut;
pub fn as_mut_slice<T>(self_: &Vec<T>) -> &mut [T] {
unsafe {
from_raw_parts_mut(self_.as_ptr() as *mut T, self_.len())
}
}
}
fn main() {
let v = vec![0,1,2];
let v1 = safe::as_mut_slice(&v);
let v2 = safe::as_mut_slice(&v);
v1[1] = 5; //~ ERROR Mut reference with non-reactivatable tag Mut(Uniq
v1[1] = 6;
}caused the following diagnostics:
Checking _buggy_as_mut_slice_9e94aa8885d2c6d92c921cd8785172ff811cc7a0 v0.1.0 (/tmp/icemaker_global_tempdir.ROAms2Xd0g8l/icemaker_clippyfix_tempdir.3ep0VPTsXiq1/_buggy_as_mut_slice_9e94aa8885d2c6d92c921cd8785172ff811cc7a0)
warning: casting the result of `as_ptr` to *mut T
--> src/main.rs:11:32
|
11 | from_raw_parts_mut(self_.as_ptr() as *mut T, self_.len())
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `self_.as_mut_ptr()`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#as_ptr_cast_mut
= note: requested on the command line with `--force-warn clippy::as-ptr-cast-mut`
warning: `_buggy_as_mut_slice_9e94aa8885d2c6d92c921cd8785172ff811cc7a0` (bin "_buggy_as_mut_slice_9e94aa8885d2c6d92c921cd8785172ff811cc7a0") generated 1 warning
Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.45s
However after applying these diagnostics, the resulting code:
// FIXME: Without retagging, optimization kills finding this problem
// compile-flags: -Zmir-opt-level=0
#![allow(unused_variables)]
mod safe {
use std::slice::from_raw_parts_mut;
pub fn as_mut_slice<T>(self_: &mut Vec<T>) -> &mut [T] {
unsafe {
from_raw_parts_mut(self_.as_mut_ptr(), self_.len())
}
}
}
fn main() {
let v = vec![0,1,2];
let v1 = safe::as_mut_slice(&v);
let v2 = safe::as_mut_slice(&v);
v1[1] = 5; //~ ERROR Mut reference with non-reactivatable tag Mut(Uniq
v1[1] = 6;
}no longer compiled:
Checking _buggy_as_mut_slice_9e94aa8885d2c6d92c921cd8785172ff811cc7a0 v0.1.0 (/tmp/icemaker_global_tempdir.ROAms2Xd0g8l/icemaker_clippyfix_tempdir.3ep0VPTsXiq1/_buggy_as_mut_slice_9e94aa8885d2c6d92c921cd8785172ff811cc7a0)
error[E0308]: mismatched types
--> src/main.rs:18:33
|
18 | let v1 = safe::as_mut_slice(&v);
| ------------------ ^^ types differ in mutability
| |
| arguments to this function are incorrect
|
= note: expected mutable reference `&mut std::vec::Vec<_>`
found reference `&std::vec::Vec<{integer}>`
note: function defined here
--> src/main.rs:9:12
|
9 | pub fn as_mut_slice<T>(self_: &mut Vec<T>) -> &mut [T] {
| ^^^^^^^^^^^^ ------------------
error[E0308]: mismatched types
--> src/main.rs:19:33
|
19 | let v2 = safe::as_mut_slice(&v);
| ------------------ ^^ types differ in mutability
| |
| arguments to this function are incorrect
|
= note: expected mutable reference `&mut std::vec::Vec<_>`
found reference `&std::vec::Vec<{integer}>`
note: function defined here
--> src/main.rs:9:12
|
9 | pub fn as_mut_slice<T>(self_: &mut Vec<T>) -> &mut [T] {
| ^^^^^^^^^^^^ ------------------
For more information about this error, try `rustc --explain E0308`.
error: could not compile `_buggy_as_mut_slice_9e94aa8885d2c6d92c921cd8785172ff811cc7a0` (bin "_buggy_as_mut_slice_9e94aa8885d2c6d92c921cd8785172ff811cc7a0") due to 2 previous errors
warning: build failed, waiting for other jobs to finish...
error: could not compile `_buggy_as_mut_slice_9e94aa8885d2c6d92c921cd8785172ff811cc7a0` (bin "_buggy_as_mut_slice_9e94aa8885d2c6d92c921cd8785172ff811cc7a0" test) due to 2 previous errors
Version:
rustc 1.90.0-nightly (855e0fe46 2025-07-11)
binary: rustc
commit-hash: 855e0fe46e68d94e9f6147531b75ac2d488c548e
commit-date: 2025-07-11
host: x86_64-unknown-linux-gnu
release: 1.90.0-nightly
LLVM version: 20.1.7