Auto merge of #89755 - jkugelman:must-use-conversions-that-move-self, r=joshtriplett

Add #[must_use] to conversions that move self

Everything here got the same message. Is the wording okay?

```rust
#[must_use = "`self` will be dropped if the result is not used"]
```

I want to draw attention to these methods in particular:

```rust
alloc::sync::Arc<MaybeUninit<T>>     unsafe fn assume_init(self) -> Arc<T>;
alloc::sync::Arc<[MaybeUninit<T>]>   unsafe fn assume_init(self) -> Arc<[T]>;
core::pin::Pin<&'a mut T>            const fn into_ref(self) -> Pin<&'a T>;
core::pin::Pin<&'a mut T>            const fn get_mut(self) -> &'a mut T;
core::pin::Pin<&'a mut T>            const unsafe fn get_unchecked_mut(self) -> &'a mut T;
core::pin::Pin<&'a mut T>            unsafe fn map_unchecked_mut(self, func: F) -> Pin<&'a mut U>;
core::pin::Pin<&'a mut Pin<P>>       fn as_deref_mut(self) -> Pin<&'a mut P::Target>;
```

Parent issue: #89692

r? `@joshtriplett`

1 files changed, 4 insertions, 0 deletions

diff --git a/library/alloc/src/string.rs b/library/alloc/src/string.rs
index d88b8e39898..d00792b9c3e 100644
--- a/library/alloc/src/string.rs
+++ b/library/alloc/src/string.rs
@@ -676,6 +676,7 @@ impl String {
     /// let rebuilt = unsafe { String::from_raw_parts(ptr, len, cap) };
     /// assert_eq!(rebuilt, "hello");
     /// ```
+    #[must_use = "`self` will be dropped if the result is not used"]
     #[unstable(feature = "vec_into_raw_parts", reason = "new API", issue = "65816")]
     pub fn into_raw_parts(self) -> (*mut u8, usize, usize) {
         self.vec.into_raw_parts()
@@ -781,6 +782,7 @@ impl String {
     /// assert_eq!(&[104, 101, 108, 108, 111][..], &bytes[..]);
     /// ```
     #[inline]
+    #[must_use = "`self` will be dropped if the result is not used"]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn into_bytes(self) -> Vec<u8> {
         self.vec
@@ -1738,6 +1740,7 @@ impl String {
     /// ```
     #[cfg(not(no_global_oom_handling))]
     #[stable(feature = "box_str", since = "1.4.0")]
+    #[must_use = "`self` will be dropped if the result is not used"]
     #[inline]
     pub fn into_boxed_str(self) -> Box<str> {
         let slice = self.vec.into_boxed_slice();
@@ -1783,6 +1786,7 @@ impl FromUtf8Error {
     ///
     /// assert_eq!(vec![0, 159], value.unwrap_err().into_bytes());
     /// ```
+    #[must_use = "`self` will be dropped if the result is not used"]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn into_bytes(self) -> Vec<u8> {
         self.bytes