Incorrect unused mut warning in 1.46.0-nightly (f455e46ea 2020-06-20) #73592
Description
CI on https://github.com/async-rs/async-std suddenly started failing as we run with deny warnings.
the error is
error: variable does not need to be mutable
##[error] --> src/io/stderr.rs:92:9
|
92 | mut self: Pin<&mut Self>,
| ----^^^^
| |
| help: remove this `mut`
|
= note: `-D unused-mut` implied by `-D warnings`
error: variable does not need to be mutable
for the following code
impl Write for Stderr {
fn poll_write(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<io::Result<usize>> {
let state = &mut *self.0.lock().unwrap();
// ...
}which stops compiling if the referenced mut is removed.
(Sorry in advance if this is known, but I couldn't find a matching issue)
CI run: https://github.com/async-rs/async-std/pull/822/checks?check_run_id=793134400
Source Code: https://github.com/async-rs/async-std/blob/master/src/io/stderr.rs#L90-L96
Edit: It seems that the nightly version might not be what triggered it, but rather a change in the underlying implementation of the lock that is being called above.
No warnings under
This issue has been assigned to @nbdd0121 via this comment.