Auto merge of #52655 - kennytm:rollup, r=kennytm

Rollup of 10 pull requests

Successful merges:

 - #52538 (Remove obsolete flags in the i586_musl Dockerfile)
 - #52548 (Cursor: update docs to clarify Cursor only works with in-memory buffers)
 - #52605 (Do not suggest using `to_owned()` on `&str += &str`)
 - #52621 (Fix color detection for Windows msys terminals.)
 - #52622 (Use MultiSpan in E0707 and E709)
 - #52627 (Compile rustc before building tests for rustdoc)
 - #52637 (Don't use NonNull::dangling as sentinel value in Rc, Arc)
 - #52640 (Forget Waker when cloning LocalWaker)
 - #52641 (Simplify 2 functions in rustc_mir/dataflow)
 - #52642 (Replace a few expect+format combos with unwrap_or_else+panic)

Failed merges:

r? @ghost

1 files changed, 5 insertions, 4 deletions

diff --git a/src/libcore/task/wake.rs b/src/libcore/task/wake.rs
index d3df8b50ee2..3b901c9aef0 100644
--- a/src/libcore/task/wake.rs
+++ b/src/libcore/task/wake.rs
@@ -12,7 +12,7 @@
             reason = "futures in libcore are unstable",
             issue = "50547")]
 
-use fmt;
+use {fmt, mem};
 use marker::Unpin;
 use ptr::NonNull;
 
@@ -166,9 +166,10 @@ impl From<LocalWaker> for Waker {
 impl Clone for LocalWaker {
     #[inline]
     fn clone(&self) -> Self {
-        unsafe {
-            LocalWaker { inner: self.inner.as_ref().clone_raw().inner }
-        }
+        let waker = unsafe { self.inner.as_ref().clone_raw() };
+        let inner = waker.inner;
+        mem::forget(waker);
+        LocalWaker { inner }
     }
 }