diff --git a/compiler/rustc_driver/src/lib.rs b/compiler/rustc_driver/src/lib.rs
index 05c7e11cbc29a..9a57ec991444a 100644
--- a/compiler/rustc_driver/src/lib.rs
+++ b/compiler/rustc_driver/src/lib.rs
@@ -1259,7 +1259,7 @@ pub fn init_env_logger(env: &str) {
};
let filter = match std::env::var(env) {
- Ok(env) => EnvFilter::from_env(env),
+ Ok(env) => EnvFilter::new(env),
_ => EnvFilter::default().add_directive(filter::Directive::from(LevelFilter::WARN)),
};
diff --git a/library/alloc/src/boxed.rs b/library/alloc/src/boxed.rs
index 85f908a7f5c7b..bd4f52560421b 100644
--- a/library/alloc/src/boxed.rs
+++ b/library/alloc/src/boxed.rs
@@ -187,6 +187,7 @@ impl<T> Box<T> {
#[cfg(not(no_global_oom_handling))]
#[inline(always)]
#[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
pub fn new(x: T) -> Self {
box x
}
@@ -211,6 +212,7 @@ impl<T> Box<T> {
/// ```
#[cfg(not(no_global_oom_handling))]
#[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
#[inline]
pub fn new_uninit() -> Box<mem::MaybeUninit<T>> {
Self::new_uninit_in(Global)
@@ -237,6 +239,7 @@ impl<T> Box<T> {
#[cfg(not(no_global_oom_handling))]
#[inline]
#[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
pub fn new_zeroed() -> Box<mem::MaybeUninit<T>> {
Self::new_zeroed_in(Global)
}
@@ -245,6 +248,7 @@ impl<T> Box<T> {
/// `x` will be pinned in memory and unable to be moved.
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "pin", since = "1.33.0")]
+ #[must_use]
#[inline(always)]
pub fn pin(x: T) -> Pin<Box<T>> {
(box x).into()
@@ -339,6 +343,7 @@ impl<T, A: Allocator> Box<T, A> {
/// ```
#[cfg(not(no_global_oom_handling))]
#[unstable(feature = "allocator_api", issue = "32838")]
+ #[must_use]
#[inline]
pub fn new_in(x: T, alloc: A) -> Self {
let mut boxed = Self::new_uninit_in(alloc);
@@ -395,6 +400,7 @@ impl<T, A: Allocator> Box<T, A> {
/// ```
#[unstable(feature = "allocator_api", issue = "32838")]
#[cfg(not(no_global_oom_handling))]
+ #[must_use]
// #[unstable(feature = "new_uninit", issue = "63291")]
pub fn new_uninit_in(alloc: A) -> Box<mem::MaybeUninit<T>, A> {
let layout = Layout::new::<mem::MaybeUninit<T>>();
@@ -459,6 +465,7 @@ impl<T, A: Allocator> Box<T, A> {
#[unstable(feature = "allocator_api", issue = "32838")]
#[cfg(not(no_global_oom_handling))]
// #[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
pub fn new_zeroed_in(alloc: A) -> Box<mem::MaybeUninit<T>, A> {
let layout = Layout::new::<mem::MaybeUninit<T>>();
// NOTE: Prefer match over unwrap_or_else since closure sometimes not inlineable.
@@ -503,6 +510,7 @@ impl<T, A: Allocator> Box<T, A> {
/// `x` will be pinned in memory and unable to be moved.
#[cfg(not(no_global_oom_handling))]
#[unstable(feature = "allocator_api", issue = "32838")]
+ #[must_use]
#[inline(always)]
pub fn pin_in(x: T, alloc: A) -> Pin<Self>
where
@@ -561,6 +569,7 @@ impl<T> Box<[T]> {
/// ```
#[cfg(not(no_global_oom_handling))]
#[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
pub fn new_uninit_slice(len: usize) -> Box<[mem::MaybeUninit<T>]> {
unsafe { RawVec::with_capacity(len).into_box(len) }
}
@@ -585,6 +594,7 @@ impl<T> Box<[T]> {
/// [zeroed]: mem::MaybeUninit::zeroed
#[cfg(not(no_global_oom_handling))]
#[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
pub fn new_zeroed_slice(len: usize) -> Box<[mem::MaybeUninit<T>]> {
unsafe { RawVec::with_capacity_zeroed(len).into_box(len) }
}
@@ -681,6 +691,7 @@ impl<T, A: Allocator> Box<[T], A> {
#[cfg(not(no_global_oom_handling))]
#[unstable(feature = "allocator_api", issue = "32838")]
// #[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
pub fn new_uninit_slice_in(len: usize, alloc: A) -> Box<[mem::MaybeUninit<T>], A> {
unsafe { RawVec::with_capacity_in(len, alloc).into_box(len) }
}
@@ -708,6 +719,7 @@ impl<T, A: Allocator> Box<[T], A> {
#[cfg(not(no_global_oom_handling))]
#[unstable(feature = "allocator_api", issue = "32838")]
// #[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
pub fn new_zeroed_slice_in(len: usize, alloc: A) -> Box<[mem::MaybeUninit<T>], A> {
unsafe { RawVec::with_capacity_zeroed_in(len, alloc).into_box(len) }
}
diff --git a/library/alloc/src/collections/binary_heap.rs b/library/alloc/src/collections/binary_heap.rs
index 4ed3702f7d224..01453e2710def 100644
--- a/library/alloc/src/collections/binary_heap.rs
+++ b/library/alloc/src/collections/binary_heap.rs
@@ -364,6 +364,7 @@ impl<T: Ord> BinaryHeap<T> {
/// heap.push(4);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
pub fn new() -> BinaryHeap<T> {
BinaryHeap { data: vec![] }
}
@@ -383,6 +384,7 @@ impl<T: Ord> BinaryHeap<T> {
/// heap.push(4);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
pub fn with_capacity(capacity: usize) -> BinaryHeap<T> {
BinaryHeap { data: Vec::with_capacity(capacity) }
}
diff --git a/library/alloc/src/collections/btree/map.rs b/library/alloc/src/collections/btree/map.rs
index d6032372168f1..7de80291cbbea 100644
--- a/library/alloc/src/collections/btree/map.rs
+++ b/library/alloc/src/collections/btree/map.rs
@@ -502,6 +502,7 @@ impl<K, V> BTreeMap<K, V> {
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_unstable(feature = "const_btree_new", issue = "71835")]
+ #[must_use]
pub const fn new() -> BTreeMap<K, V> {
BTreeMap { root: None, length: 0 }
}
diff --git a/library/alloc/src/collections/btree/set.rs b/library/alloc/src/collections/btree/set.rs
index f4c1010098256..d732f65b0d05f 100644
--- a/library/alloc/src/collections/btree/set.rs
+++ b/library/alloc/src/collections/btree/set.rs
@@ -248,6 +248,7 @@ impl<T> BTreeSet<T> {
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_unstable(feature = "const_btree_new", issue = "71835")]
+ #[must_use]
pub const fn new() -> BTreeSet<T> {
BTreeSet { map: BTreeMap::new() }
}
diff --git a/library/alloc/src/collections/linked_list.rs b/library/alloc/src/collections/linked_list.rs
index a769c558b4fa9..6dcba318c3598 100644
--- a/library/alloc/src/collections/linked_list.rs
+++ b/library/alloc/src/collections/linked_list.rs
@@ -417,6 +417,7 @@ impl<T> LinkedList<T> {
#[inline]
#[rustc_const_stable(feature = "const_linked_list_new", since = "1.32.0")]
#[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
pub const fn new() -> Self {
LinkedList { head: None, tail: None, len: 0, marker: PhantomData }
}
diff --git a/library/alloc/src/collections/vec_deque/mod.rs b/library/alloc/src/collections/vec_deque/mod.rs
index e996784bbad28..09ae1f7eebd09 100644
--- a/library/alloc/src/collections/vec_deque/mod.rs
+++ b/library/alloc/src/collections/vec_deque/mod.rs
@@ -475,6 +475,7 @@ impl<T> VecDeque<T> {
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
pub fn new() -> VecDeque<T> {
VecDeque::new_in(Global)
}
@@ -490,6 +491,7 @@ impl<T> VecDeque<T> {
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
pub fn with_capacity(capacity: usize) -> VecDeque<T> {
Self::with_capacity_in(capacity, Global)
}
diff --git a/library/alloc/src/raw_vec.rs b/library/alloc/src/raw_vec.rs
index be21018512d8b..75dbd4678bb47 100644
--- a/library/alloc/src/raw_vec.rs
+++ b/library/alloc/src/raw_vec.rs
@@ -69,6 +69,7 @@ impl<T> RawVec<T, Global> {
/// `RawVec` with capacity `0`. If `T` is zero-sized, then it makes a
/// `RawVec` with capacity `usize::MAX`. Useful for implementing
/// delayed allocation.
+ #[must_use]
pub const fn new() -> Self {
Self::new_in(Global)
}
@@ -87,6 +88,7 @@ impl<T> RawVec<T, Global> {
///
/// Aborts on OOM.
#[cfg(not(no_global_oom_handling))]
+ #[must_use]
#[inline]
pub fn with_capacity(capacity: usize) -> Self {
Self::with_capacity_in(capacity, Global)
@@ -94,6 +96,7 @@ impl<T> RawVec<T, Global> {
/// Like `with_capacity`, but guarantees the buffer is zeroed.
#[cfg(not(no_global_oom_handling))]
+ #[must_use]
#[inline]
pub fn with_capacity_zeroed(capacity: usize) -> Self {
Self::with_capacity_zeroed_in(capacity, Global)
diff --git a/library/alloc/src/rc.rs b/library/alloc/src/rc.rs
index 81e97805a7214..bde0dc754fb32 100644
--- a/library/alloc/src/rc.rs
+++ b/library/alloc/src/rc.rs
@@ -452,6 +452,7 @@ impl<T> Rc<T> {
/// ```
#[cfg(not(no_global_oom_handling))]
#[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
pub fn new_uninit() -> Rc<mem::MaybeUninit<T>> {
unsafe {
Rc::from_ptr(Rc::allocate_for_layout(
@@ -484,6 +485,7 @@ impl<T> Rc<T> {
/// [zeroed]: mem::MaybeUninit::zeroed
#[cfg(not(no_global_oom_handling))]
#[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
pub fn new_zeroed() -> Rc<mem::MaybeUninit<T>> {
unsafe {
Rc::from_ptr(Rc::allocate_for_layout(
@@ -587,6 +589,7 @@ impl<T> Rc<T> {
/// `value` will be pinned in memory and unable to be moved.
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "pin", since = "1.33.0")]
+ #[must_use]
pub fn pin(value: T) -> Pin<Rc<T>> {
unsafe { Pin::new_unchecked(Rc::new(value)) }
}
@@ -658,6 +661,7 @@ impl<T> Rc<[T]> {
/// ```
#[cfg(not(no_global_oom_handling))]
#[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
pub fn new_uninit_slice(len: usize) -> Rc<[mem::MaybeUninit<T>]> {
unsafe { Rc::from_ptr(Rc::allocate_for_slice(len)) }
}
@@ -684,6 +688,7 @@ impl<T> Rc<[T]> {
/// [zeroed]: mem::MaybeUninit::zeroed
#[cfg(not(no_global_oom_handling))]
#[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
pub fn new_zeroed_slice(len: usize) -> Rc<[mem::MaybeUninit<T>]> {
unsafe {
Rc::from_ptr(Rc::allocate_for_layout(
@@ -2044,6 +2049,7 @@ impl<T> Weak<T> {
/// assert!(empty.upgrade().is_none());
/// ```
#[stable(feature = "downgraded_weak", since = "1.10.0")]
+ #[must_use]
pub fn new() -> Weak<T> {
Weak { ptr: NonNull::new(usize::MAX as *mut RcBox<T>).expect("MAX is not 0") }
}
diff --git a/library/alloc/src/str.rs b/library/alloc/src/str.rs
index 2900d01d9bdae..ac7f230445656 100644
--- a/library/alloc/src/str.rs
+++ b/library/alloc/src/str.rs
@@ -595,6 +595,7 @@ impl str {
/// assert_eq!("☺", &*smile);
/// ```
#[stable(feature = "str_box_extras", since = "1.20.0")]
+#[must_use]
#[inline]
pub unsafe fn from_boxed_utf8_unchecked(v: Box<[u8]>) -> Box<str> {
unsafe { Box::from_raw(Box::into_raw(v) as *mut str) }
diff --git a/library/alloc/src/string.rs b/library/alloc/src/string.rs
index d88b8e398985a..2c8302b5dc9fc 100644
--- a/library/alloc/src/string.rs
+++ b/library/alloc/src/string.rs
@@ -378,6 +378,7 @@ impl String {
#[inline]
#[rustc_const_stable(feature = "const_string_new", since = "1.39.0")]
#[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
pub const fn new() -> String {
String { vec: Vec::new() }
}
@@ -422,6 +423,7 @@ impl String {
#[cfg(not(no_global_oom_handling))]
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
pub fn with_capacity(capacity: usize) -> String {
String { vec: Vec::with_capacity(capacity) }
}
@@ -761,6 +763,7 @@ impl String {
/// assert_eq!("💖", sparkle_heart);
/// ```
#[inline]
+ #[must_use]
#[stable(feature = "rust1", since = "1.0.0")]
pub unsafe fn from_utf8_unchecked(bytes: Vec<u8>) -> String {
String { vec: bytes }
diff --git a/library/alloc/src/sync.rs b/library/alloc/src/sync.rs
index 6e8da849e64cd..482c3eac5f970 100644
--- a/library/alloc/src/sync.rs
+++ b/library/alloc/src/sync.rs
@@ -448,6 +448,7 @@ impl<T> Arc<T> {
/// ```
#[cfg(not(no_global_oom_handling))]
#[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
pub fn new_uninit() -> Arc<mem::MaybeUninit<T>> {
unsafe {
Arc::from_ptr(Arc::allocate_for_layout(
@@ -480,6 +481,7 @@ impl<T> Arc<T> {
/// [zeroed]: mem::MaybeUninit::zeroed
#[cfg(not(no_global_oom_handling))]
#[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
pub fn new_zeroed() -> Arc<mem::MaybeUninit<T>> {
unsafe {
Arc::from_ptr(Arc::allocate_for_layout(
@@ -494,6 +496,7 @@ impl<T> Arc<T> {
/// `data` will be pinned in memory and unable to be moved.
#[cfg(not(no_global_oom_handling))]
#[stable(feature = "pin", since = "1.33.0")]
+ #[must_use]
pub fn pin(data: T) -> Pin<Arc<T>> {
unsafe { Pin::new_unchecked(Arc::new(data)) }
}
@@ -662,6 +665,7 @@ impl<T> Arc<[T]> {
/// ```
#[cfg(not(no_global_oom_handling))]
#[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
pub fn new_uninit_slice(len: usize) -> Arc<[mem::MaybeUninit<T>]> {
unsafe { Arc::from_ptr(Arc::allocate_for_slice(len)) }
}
@@ -688,6 +692,7 @@ impl<T> Arc<[T]> {
/// [zeroed]: mem::MaybeUninit::zeroed
#[cfg(not(no_global_oom_handling))]
#[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
pub fn new_zeroed_slice(len: usize) -> Arc<[mem::MaybeUninit<T>]> {
unsafe {
Arc::from_ptr(Arc::allocate_for_layout(
@@ -1678,6 +1683,7 @@ impl<T> Weak<T> {
/// assert!(empty.upgrade().is_none());
/// ```
#[stable(feature = "downgraded_weak", since = "1.10.0")]
+ #[must_use]
pub fn new() -> Weak<T> {
Weak { ptr: NonNull::new(usize::MAX as *mut ArcInner<T>).expect("MAX is not 0") }
}
diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index 4f18a054a0d98..a12acb1a1c07f 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -420,6 +420,7 @@ impl<T> Vec<T> {
#[inline]
#[rustc_const_stable(feature = "const_vec_new", since = "1.39.0")]
#[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
pub const fn new() -> Self {
Vec { buf: RawVec::NEW, len: 0 }
}
@@ -464,6 +465,7 @@ impl<T> Vec<T> {
#[cfg(not(no_global_oom_handling))]
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
pub fn with_capacity(capacity: usize) -> Self {
Self::with_capacity_in(capacity, Global)
}
diff --git a/library/core/src/alloc/layout.rs b/library/core/src/alloc/layout.rs
index ccf6e420de7a9..d4c8ea33501a6 100644
--- a/library/core/src/alloc/layout.rs
+++ b/library/core/src/alloc/layout.rs
@@ -94,6 +94,7 @@ impl Layout {
/// [`Layout::from_size_align`].
#[stable(feature = "alloc_layout", since = "1.28.0")]
#[rustc_const_stable(feature = "alloc_layout", since = "1.36.0")]
+ #[must_use]
#[inline]
pub const unsafe fn from_size_align_unchecked(size: usize, align: usize) -> Self {
// SAFETY: the caller must ensure that `align` is greater than zero.
@@ -119,6 +120,7 @@ impl Layout {
/// Constructs a `Layout` suitable for holding a value of type `T`.
#[stable(feature = "alloc_layout", since = "1.28.0")]
#[rustc_const_stable(feature = "alloc_layout_const_new", since = "1.42.0")]
+ #[must_use]
#[inline]
pub const fn new<T>() -> Self {
let (size, align) = size_align::<T>();
diff --git a/library/core/src/char/convert.rs b/library/core/src/char/convert.rs
index 7a0ec32cc61a9..72921414fb3f2 100644
--- a/library/core/src/char/convert.rs
+++ b/library/core/src/char/convert.rs
@@ -48,6 +48,7 @@ use super::MAX;
/// assert_eq!(None, c);
/// ```
#[doc(alias = "chr")]
+#[must_use]
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn from_u32(i: u32) -> Option<char> {
@@ -88,6 +89,7 @@ pub fn from_u32(i: u32) -> Option<char> {
/// assert_eq!('❤', c);
/// ```
#[inline]
+#[must_use]
#[stable(feature = "char_from_unchecked", since = "1.5.0")]
pub unsafe fn from_u32_unchecked(i: u32) -> char {
// SAFETY: the caller must guarantee that `i` is a valid char value.
@@ -319,6 +321,7 @@ impl fmt::Display for CharTryFromError {
/// let c = char::from_digit(1, 37);
/// ```
#[inline]
+#[must_use]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn from_digit(num: u32, radix: u32) -> Option<char> {
if radix > 36 {
diff --git a/library/core/src/char/methods.rs b/library/core/src/char/methods.rs
index 45f7540d314be..3e7c5b3189cb5 100644
--- a/library/core/src/char/methods.rs
+++ b/library/core/src/char/methods.rs
@@ -136,6 +136,7 @@ impl char {
/// assert_eq!(None, c);
/// ```
#[stable(feature = "assoc_char_funcs", since = "1.52.0")]
+ #[must_use]
#[inline]
pub fn from_u32(i: u32) -> Option<char> {
super::convert::from_u32(i)
@@ -177,6 +178,7 @@ impl char {
/// assert_eq!('❤', c);
/// ```
#[stable(feature = "assoc_char_funcs", since = "1.52.0")]
+ #[must_use]
#[inline]
pub unsafe fn from_u32_unchecked(i: u32) -> char {
// SAFETY: the safety contract must be upheld by the caller.
@@ -230,9 +232,10 @@ impl char {
/// use std::char;
///
/// // this panics
- /// char::from_digit(1, 37);
+ /// let _c = char::from_digit(1, 37);
/// ```
#[stable(feature = "assoc_char_funcs", since = "1.52.0")]
+ #[must_use]
#[inline]
pub fn from_digit(num: u32, radix: u32) -> Option<char> {
super::convert::from_digit(num, radix)
diff --git a/library/core/src/hash/sip.rs b/library/core/src/hash/sip.rs
index 6178b0af137e8..b9443e30074b0 100644
--- a/library/core/src/hash/sip.rs
+++ b/library/core/src/hash/sip.rs
@@ -157,6 +157,7 @@ impl SipHasher {
since = "1.13.0",
reason = "use `std::collections::hash_map::DefaultHasher` instead"
)]
+ #[must_use]
pub fn new() -> SipHasher {
SipHasher::new_with_keys(0, 0)
}
@@ -168,6 +169,7 @@ impl SipHasher {
since = "1.13.0",
reason = "use `std::collections::hash_map::DefaultHasher` instead"
)]
+ #[must_use]
pub fn new_with_keys(key0: u64, key1: u64) -> SipHasher {
SipHasher(SipHasher24 { hasher: Hasher::new_with_keys(key0, key1) })
}
diff --git a/library/core/src/lazy.rs b/library/core/src/lazy.rs
index e6bea462fa99a..d109141216aef 100644
--- a/library/core/src/lazy.rs
+++ b/library/core/src/lazy.rs
@@ -83,6 +83,7 @@ impl<T> From<T> for OnceCell<T> {
impl<T> OnceCell<T> {
/// Creates a new empty cell.
#[unstable(feature = "once_cell", issue = "74465")]
+ #[must_use]
pub const fn new() -> OnceCell<T> {
OnceCell { inner: UnsafeCell::new(None) }
}
diff --git a/library/core/src/mem/maybe_uninit.rs b/library/core/src/mem/maybe_uninit.rs
index 9c88a62336161..b9772eaa67813 100644
--- a/library/core/src/mem/maybe_uninit.rs
+++ b/library/core/src/mem/maybe_uninit.rs
@@ -312,6 +312,7 @@ impl<T> MaybeUninit<T> {
/// ```
#[stable(feature = "maybe_uninit", since = "1.36.0")]
#[rustc_const_stable(feature = "const_maybe_uninit", since = "1.36.0")]
+ #[must_use]
#[inline(always)]
#[rustc_diagnostic_item = "maybe_uninit_uninit"]
pub const fn uninit() -> MaybeUninit<T> {
@@ -349,6 +350,7 @@ impl<T> MaybeUninit<T> {
/// ```
#[unstable(feature = "maybe_uninit_uninit_array", issue = "none")]
#[rustc_const_unstable(feature = "maybe_uninit_uninit_array", issue = "none")]
+ #[must_use]
#[inline(always)]
pub const fn uninit_array<const LEN: usize>() -> [Self; LEN] {
// SAFETY: An uninitialized `[MaybeUninit<_>; LEN]` is valid.
@@ -391,6 +393,7 @@ impl<T> MaybeUninit<T> {
/// // This is undefined behavior. ⚠️
/// ```
#[stable(feature = "maybe_uninit", since = "1.36.0")]
+ #[must_use]
#[inline]
#[rustc_diagnostic_item = "maybe_uninit_zeroed"]
pub fn zeroed() -> MaybeUninit<T> {
diff --git a/library/core/src/num/f32.rs b/library/core/src/num/f32.rs
index 4073a38b3cd85..ad8106df198da 100644
--- a/library/core/src/num/f32.rs
+++ b/library/core/src/num/f32.rs
@@ -801,6 +801,7 @@ impl f32 {
/// ```
#[stable(feature = "float_bits_conv", since = "1.20.0")]
#[rustc_const_unstable(feature = "const_float_bits_conv", issue = "72447")]
+ #[must_use]
#[inline]
pub const fn from_bits(v: u32) -> Self {
// SAFETY: `u32` is a plain old datatype so we can always transmute from it
@@ -885,6 +886,7 @@ impl f32 {
/// ```
#[stable(feature = "float_to_from_bytes", since = "1.40.0")]
#[rustc_const_unstable(feature = "const_float_bits_conv", issue = "72447")]
+ #[must_use]
#[inline]
pub const fn from_be_bytes(bytes: [u8; 4]) -> Self {
Self::from_bits(u32::from_be_bytes(bytes))
@@ -900,6 +902,7 @@ impl f32 {
/// ```
#[stable(feature = "float_to_from_bytes", since = "1.40.0")]
#[rustc_const_unstable(feature = "const_float_bits_conv", issue = "72447")]
+ #[must_use]
#[inline]
pub const fn from_le_bytes(bytes: [u8; 4]) -> Self {
Self::from_bits(u32::from_le_bytes(bytes))
@@ -926,6 +929,7 @@ impl f32 {
/// ```
#[stable(feature = "float_to_from_bytes", since = "1.40.0")]
#[rustc_const_unstable(feature = "const_float_bits_conv", issue = "72447")]
+ #[must_use]
#[inline]
pub const fn from_ne_bytes(bytes: [u8; 4]) -> Self {
Self::from_bits(u32::from_ne_bytes(bytes))
diff --git a/library/core/src/num/f64.rs b/library/core/src/num/f64.rs
index c6ccff0398000..6a48101e04fda 100644
--- a/library/core/src/num/f64.rs
+++ b/library/core/src/num/f64.rs
@@ -817,6 +817,7 @@ impl f64 {
/// ```
#[stable(feature = "float_bits_conv", since = "1.20.0")]
#[rustc_const_unstable(feature = "const_float_bits_conv", issue = "72447")]
+ #[must_use]
#[inline]
pub const fn from_bits(v: u64) -> Self {
// SAFETY: `u64` is a plain old datatype so we can always transmute from it
@@ -901,6 +902,7 @@ impl f64 {
/// ```
#[stable(feature = "float_to_from_bytes", since = "1.40.0")]
#[rustc_const_unstable(feature = "const_float_bits_conv", issue = "72447")]
+ #[must_use]
#[inline]
pub const fn from_be_bytes(bytes: [u8; 8]) -> Self {
Self::from_bits(u64::from_be_bytes(bytes))
@@ -916,6 +918,7 @@ impl f64 {
/// ```
#[stable(feature = "float_to_from_bytes", since = "1.40.0")]
#[rustc_const_unstable(feature = "const_float_bits_conv", issue = "72447")]
+ #[must_use]
#[inline]
pub const fn from_le_bytes(bytes: [u8; 8]) -> Self {
Self::from_bits(u64::from_le_bytes(bytes))
@@ -942,6 +945,7 @@ impl f64 {
/// ```
#[stable(feature = "float_to_from_bytes", since = "1.40.0")]
#[rustc_const_unstable(feature = "const_float_bits_conv", issue = "72447")]
+ #[must_use]
#[inline]
pub const fn from_ne_bytes(bytes: [u8; 8]) -> Self {
Self::from_bits(u64::from_ne_bytes(bytes))
diff --git a/library/core/src/num/int_macros.rs b/library/core/src/num/int_macros.rs
index c90e301a9dd50..0bdc933013791 100644
--- a/library/core/src/num/int_macros.rs
+++ b/library/core/src/num/int_macros.rs
@@ -297,6 +297,7 @@ macro_rules! int_impl {
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")]
+ #[must_use]
#[inline]
pub const fn from_be(x: Self) -> Self {
#[cfg(target_endian = "big")]
@@ -328,6 +329,7 @@ macro_rules! int_impl {
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")]
+ #[must_use]
#[inline]
pub const fn from_le(x: Self) -> Self {
#[cfg(target_endian = "little")]
@@ -2671,6 +2673,7 @@ macro_rules! int_impl {
/// ```
#[stable(feature = "int_to_from_bytes", since = "1.32.0")]
#[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
+ #[must_use]
#[inline]
pub const fn from_be_bytes(bytes: [u8; mem::size_of::<Self>()]) -> Self {
Self::from_be(Self::from_ne_bytes(bytes))
@@ -2701,6 +2704,7 @@ macro_rules! int_impl {
/// ```
#[stable(feature = "int_to_from_bytes", since = "1.32.0")]
#[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
+ #[must_use]
#[inline]
pub const fn from_le_bytes(bytes: [u8; mem::size_of::<Self>()]) -> Self {
Self::from_le(Self::from_ne_bytes(bytes))
@@ -2742,6 +2746,7 @@ macro_rules! int_impl {
/// ```
#[stable(feature = "int_to_from_bytes", since = "1.32.0")]
#[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
+ #[must_use]
// SAFETY: const sound because integers are plain old datatypes so we can always
// transmute to them
#[inline]
diff --git a/library/core/src/num/nonzero.rs b/library/core/src/num/nonzero.rs
index 4bb659db3a011..89fd9fbaf455d 100644
--- a/library/core/src/num/nonzero.rs
+++ b/library/core/src/num/nonzero.rs
@@ -50,6 +50,7 @@ macro_rules! nonzero_integers {
/// The value must not be zero.
#[$stability]
#[$const_new_unchecked_stability]
+ #[must_use]
#[inline]
pub const unsafe fn new_unchecked(n: $Int) -> Self {
// SAFETY: this is guaranteed to be safe by the caller.
@@ -59,6 +60,7 @@ macro_rules! nonzero_integers {
/// Creates a non-zero if the given value is not zero.
#[$stability]
#[rustc_const_stable(feature = "const_nonzero_int_methods", since = "1.47.0")]
+ #[must_use]
#[inline]
pub const fn new(n: $Int) -> Option<Self> {
if n != 0 {
diff --git a/library/core/src/num/saturating.rs b/library/core/src/num/saturating.rs
index eeaaf38e61dfb..c764f420e2739 100644
--- a/library/core/src/num/saturating.rs
+++ b/library/core/src/num/saturating.rs
@@ -657,6 +657,7 @@ macro_rules! saturating_int_impl {
/// }
/// ```
#[inline]
+ #[must_use]
#[unstable(feature = "saturating_int_impl", issue = "87920")]
pub const fn from_be(x: Self) -> Self {
Saturating(<$t>::from_be(x.0))
@@ -684,6 +685,7 @@ macro_rules! saturating_int_impl {
/// }
/// ```
#[inline]
+ #[must_use]
#[unstable(feature = "saturating_int_impl", issue = "87920")]
pub const fn from_le(x: Self) -> Self {
Saturating(<$t>::from_le(x.0))
diff --git a/library/core/src/num/uint_macros.rs b/library/core/src/num/uint_macros.rs
index 2a3663f2c0fde..c3b2ecdb30f5b 100644
--- a/library/core/src/num/uint_macros.rs
+++ b/library/core/src/num/uint_macros.rs
@@ -300,6 +300,7 @@ macro_rules! uint_impl {
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
+ #[must_use]
#[inline(always)]
pub const fn from_be(x: Self) -> Self {
#[cfg(target_endian = "big")]
@@ -332,6 +333,7 @@ macro_rules! uint_impl {
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
+ #[must_use]
#[inline(always)]
pub const fn from_le(x: Self) -> Self {
#[cfg(target_endian = "little")]
@@ -2321,6 +2323,7 @@ macro_rules! uint_impl {
/// ```
#[stable(feature = "int_to_from_bytes", since = "1.32.0")]
#[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
+ #[must_use]
#[inline]
pub const fn from_be_bytes(bytes: [u8; mem::size_of::<Self>()]) -> Self {
Self::from_be(Self::from_ne_bytes(bytes))
@@ -2351,6 +2354,7 @@ macro_rules! uint_impl {
/// ```
#[stable(feature = "int_to_from_bytes", since = "1.32.0")]
#[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
+ #[must_use]
#[inline]
pub const fn from_le_bytes(bytes: [u8; mem::size_of::<Self>()]) -> Self {
Self::from_le(Self::from_ne_bytes(bytes))
@@ -2392,6 +2396,7 @@ macro_rules! uint_impl {
/// ```
#[stable(feature = "int_to_from_bytes", since = "1.32.0")]
#[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
+ #[must_use]
// SAFETY: const sound because integers are plain old datatypes so we can always
// transmute to them
#[inline]
diff --git a/library/core/src/num/wrapping.rs b/library/core/src/num/wrapping.rs
index 66620fc8fd14d..f387bd5b41cc4 100644
--- a/library/core/src/num/wrapping.rs
+++ b/library/core/src/num/wrapping.rs
@@ -651,6 +651,7 @@ macro_rules! wrapping_int_impl {
/// }
/// ```
#[inline]
+ #[must_use]
#[unstable(feature = "wrapping_int_impl", issue = "32463")]
pub const fn from_be(x: Self) -> Self {
Wrapping(<$t>::from_be(x.0))
@@ -678,6 +679,7 @@ macro_rules! wrapping_int_impl {
/// }
/// ```
#[inline]
+ #[must_use]
#[unstable(feature = "wrapping_int_impl", issue = "32463")]
pub const fn from_le(x: Self) -> Self {
Wrapping(<$t>::from_le(x.0))
diff --git a/library/core/src/str/converts.rs b/library/core/src/str/converts.rs
index da6ef1b6678c6..ed9f49f159611 100644
--- a/library/core/src/str/converts.rs
+++ b/library/core/src/str/converts.rs
@@ -155,6 +155,7 @@ pub fn from_utf8_mut(v: &mut [u8]) -> Result<&mut str, Utf8Error> {
/// assert_eq!("💖", sparkle_heart);
/// ```
#[inline]
+#[must_use]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_str_from_utf8_unchecked", since = "1.55.0")]
pub const unsafe fn from_utf8_unchecked(v: &[u8]) -> &str {
@@ -181,6 +182,7 @@ pub const unsafe fn from_utf8_unchecked(v: &[u8]) -> &str {
/// assert_eq!("💖", heart);
/// ```
#[inline]
+#[must_use]
#[stable(feature = "str_mut_extras", since = "1.20.0")]
pub unsafe fn from_utf8_unchecked_mut(v: &mut [u8]) -> &mut str {
// SAFETY: the caller must guarantee that the bytes `v`
diff --git a/library/core/src/str/lossy.rs b/library/core/src/str/lossy.rs
index 720a35bbc8f2c..d3c9d21c3c756 100644
--- a/library/core/src/str/lossy.rs
+++ b/library/core/src/str/lossy.rs
@@ -12,10 +12,12 @@ pub struct Utf8Lossy {
}
impl Utf8Lossy {
+ #[must_use]
pub fn from_str(s: &str) -> &Utf8Lossy {
Utf8Lossy::from_bytes(s.as_bytes())
}
+ #[must_use]
pub fn from_bytes(bytes: &[u8]) -> &Utf8Lossy {
// SAFETY: Both use the same memory layout, and UTF-8 correctness isn't required.
unsafe { mem::transmute(bytes) }
diff --git a/library/core/src/sync/atomic.rs b/library/core/src/sync/atomic.rs
index d9de37e9c5197..b07752116e514 100644
--- a/library/core/src/sync/atomic.rs
+++ b/library/core/src/sync/atomic.rs
@@ -290,6 +290,7 @@ impl AtomicBool {
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_atomic_new", since = "1.24.0")]
+ #[must_use]
pub const fn new(v: bool) -> AtomicBool {
AtomicBool { v: UnsafeCell::new(v as u8) }
}
@@ -1392,6 +1393,7 @@ macro_rules! atomic_int {
#[inline]
#[$stable]
#[$const_stable]
+ #[must_use]
pub const fn new(v: $int_type) -> Self {
Self {v: UnsafeCell::new(v)}
}
diff --git a/library/core/src/task/wake.rs b/library/core/src/task/wake.rs
index b775e022a54b4..620bff5387994 100644
--- a/library/core/src/task/wake.rs
+++ b/library/core/src/task/wake.rs
@@ -39,6 +39,7 @@ impl RawWaker {
#[rustc_promotable]
#[stable(feature = "futures_api", since = "1.36.0")]
#[rustc_const_stable(feature = "futures_api", since = "1.36.0")]
+ #[must_use]
pub const fn new(data: *const (), vtable: &'static RawWakerVTable) -> RawWaker {
RawWaker { data, vtable }
}
@@ -158,6 +159,7 @@ pub struct Context<'a> {
impl<'a> Context<'a> {
/// Create a new `Context` from a `&Waker`.
#[stable(feature = "futures_api", since = "1.36.0")]
+ #[must_use]
#[inline]
pub fn from_waker(waker: &'a Waker) -> Self {
Context { waker, _marker: PhantomData }
@@ -251,6 +253,7 @@ impl Waker {
/// in [`RawWaker`]'s and [`RawWakerVTable`]'s documentation is not upheld.
/// Therefore this method is unsafe.
#[inline]
+ #[must_use]
#[stable(feature = "futures_api", since = "1.36.0")]
pub unsafe fn from_raw(waker: RawWaker) -> Waker {
Waker { waker }
diff --git a/library/core/src/time.rs b/library/core/src/time.rs
index e1408c7cc2ecc..40c5338d13cfd 100644
--- a/library/core/src/time.rs
+++ b/library/core/src/time.rs
@@ -181,6 +181,7 @@ impl Duration {
#[stable(feature = "duration", since = "1.3.0")]
#[inline]
#[rustc_const_unstable(feature = "duration_consts_2", issue = "72440")]
+ #[must_use]
pub const fn new(secs: u64, nanos: u32) -> Duration {
let secs = match secs.checked_add((nanos / NANOS_PER_SEC) as u64) {
Some(secs) => secs,
@@ -203,6 +204,7 @@ impl Duration {
/// assert_eq!(0, duration.subsec_nanos());
/// ```
#[stable(feature = "duration", since = "1.3.0")]
+ #[must_use]
#[inline]
#[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
pub const fn from_secs(secs: u64) -> Duration {
@@ -222,6 +224,7 @@ impl Duration {
/// assert_eq!(569_000_000, duration.subsec_nanos());
/// ```
#[stable(feature = "duration", since = "1.3.0")]
+ #[must_use]
#[inline]
#[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
pub const fn from_millis(millis: u64) -> Duration {
@@ -244,6 +247,7 @@ impl Duration {
/// assert_eq!(2000, duration.subsec_nanos());
/// ```
#[stable(feature = "duration_from_micros", since = "1.27.0")]
+ #[must_use]
#[inline]
#[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
pub const fn from_micros(micros: u64) -> Duration {
@@ -266,6 +270,7 @@ impl Duration {
/// assert_eq!(123, duration.subsec_nanos());
/// ```
#[stable(feature = "duration_extras", since = "1.27.0")]
+ #[must_use]
#[inline]
#[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
pub const fn from_nanos(nanos: u64) -> Duration {
@@ -707,6 +712,7 @@ impl Duration {
/// assert_eq!(dur, Duration::new(2, 700_000_000));
/// ```
#[stable(feature = "duration_float", since = "1.38.0")]
+ #[must_use]
#[inline]
#[rustc_const_unstable(feature = "duration_consts_2", issue = "72440")]
pub const fn from_secs_f64(secs: f64) -> Duration {
@@ -768,6 +774,7 @@ impl Duration {
/// assert_eq!(dur, Duration::new(2, 700_000_000));
/// ```
#[stable(feature = "duration_float", since = "1.38.0")]
+ #[must_use]
#[inline]
#[rustc_const_unstable(feature = "duration_consts_2", issue = "72440")]
pub const fn from_secs_f32(secs: f32) -> Duration {
diff --git a/library/std/src/collections/hash/map.rs b/library/std/src/collections/hash/map.rs
index 528bb1bf6e9f9..7fa2e3ed3f6ac 100644
--- a/library/std/src/collections/hash/map.rs
+++ b/library/std/src/collections/hash/map.rs
@@ -223,6 +223,7 @@ impl<K, V> HashMap<K, V, RandomState> {
/// let mut map: HashMap<&str, i32> = HashMap::new();
/// ```
#[inline]
+ #[must_use]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn new() -> HashMap<K, V, RandomState> {
Default::default()
@@ -240,6 +241,7 @@ impl<K, V> HashMap<K, V, RandomState> {
/// let mut map: HashMap<&str, i32> = HashMap::with_capacity(10);
/// ```
#[inline]
+ #[must_use]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn with_capacity(capacity: usize) -> HashMap<K, V, RandomState> {
HashMap::with_capacity_and_hasher(capacity, Default::default())
@@ -2891,6 +2893,7 @@ impl RandomState {
#[inline]
#[allow(deprecated)]
// rand
+ #[must_use]
#[stable(feature = "hashmap_build_hasher", since = "1.7.0")]
pub fn new() -> RandomState {
// Historically this function did not cache keys from the OS and instead
@@ -2943,6 +2946,7 @@ impl DefaultHasher {
/// instances created through `new` or `default`.
#[stable(feature = "hashmap_default_hasher", since = "1.13.0")]
#[allow(deprecated)]
+ #[must_use]
pub fn new() -> DefaultHasher {
DefaultHasher(SipHasher13::new_with_keys(0, 0))
}
diff --git a/library/std/src/collections/hash/set.rs b/library/std/src/collections/hash/set.rs
index dcfe322095082..5804701892e6e 100644
--- a/library/std/src/collections/hash/set.rs
+++ b/library/std/src/collections/hash/set.rs
@@ -126,6 +126,7 @@ impl<T> HashSet<T, RandomState> {
/// let set: HashSet<i32> = HashSet::new();
/// ```
#[inline]
+ #[must_use]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn new() -> HashSet<T, RandomState> {
Default::default()
@@ -144,6 +145,7 @@ impl<T> HashSet<T, RandomState> {
/// assert!(set.capacity() >= 10);
/// ```
#[inline]
+ #[must_use]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn with_capacity(capacity: usize) -> HashSet<T, RandomState> {
HashSet { base: base::HashSet::with_capacity_and_hasher(capacity, Default::default()) }
diff --git a/library/std/src/ffi/c_str.rs b/library/std/src/ffi/c_str.rs
index fe1f28f00c403..e290350993d73 100644
--- a/library/std/src/ffi/c_str.rs
+++ b/library/std/src/ffi/c_str.rs
@@ -425,6 +425,7 @@ impl CString {
/// let c_string = CString::from_vec_unchecked(raw);
/// }
/// ```
+ #[must_use]
#[stable(feature = "rust1", since = "1.0.0")]
pub unsafe fn from_vec_unchecked(mut v: Vec<u8>) -> CString {
v.reserve_exact(1);
@@ -476,6 +477,7 @@ impl CString {
/// let c_string = CString::from_raw(raw);
/// }
/// ```
+ #[must_use = "call `drop(from_raw(ptr))` if you intend to drop the `CString`"]
#[stable(feature = "cstr_memory", since = "1.4.0")]
pub unsafe fn from_raw(ptr: *mut c_char) -> CString {
// SAFETY: This is called with a pointer that was obtained from a call
@@ -701,6 +703,7 @@ impl CString {
/// unsafe { CString::from_vec_unchecked(b"abc".to_vec()) }
/// );
/// ```
+ #[must_use]
#[unstable(feature = "cstring_from_vec_with_nul", issue = "73179")]
pub unsafe fn from_vec_with_nul_unchecked(v: Vec<u8>) -> Self {
Self { inner: v.into_boxed_slice() }
@@ -1162,6 +1165,7 @@ impl CStr {
/// }
/// # }
/// ```
+ #[must_use]
#[stable(feature = "rust1", since = "1.0.0")]
pub unsafe fn from_ptr<'a>(ptr: *const c_char) -> &'a CStr {
// SAFETY: The caller has provided a pointer that points to a valid C
@@ -1244,6 +1248,7 @@ impl CStr {
/// }
/// ```
#[inline]
+ #[must_use]
#[stable(feature = "cstr_from_bytes", since = "1.10.0")]
#[rustc_const_unstable(feature = "const_cstr_unchecked", issue = "none")]
pub const unsafe fn from_bytes_with_nul_unchecked(bytes: &[u8]) -> &CStr {
diff --git a/library/std/src/ffi/os_str.rs b/library/std/src/ffi/os_str.rs
index c305519dd4461..e4ad6cba88046 100644
--- a/library/std/src/ffi/os_str.rs
+++ b/library/std/src/ffi/os_str.rs
@@ -119,6 +119,7 @@ impl OsString {
/// let os_string = OsString::new();
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
#[inline]
pub fn new() -> OsString {
OsString { inner: Buf::from_string(String::new()) }
@@ -199,6 +200,7 @@ impl OsString {
/// assert_eq!(capacity, os_string.capacity());
/// ```
#[stable(feature = "osstring_simple_functions", since = "1.9.0")]
+ #[must_use]
#[inline]
pub fn with_capacity(capacity: usize) -> OsString {
OsString { inner: Buf::with_capacity(capacity) }
diff --git a/library/std/src/fs.rs b/library/std/src/fs.rs
index 726c855c4fd36..85d350729239c 100644
--- a/library/std/src/fs.rs
+++ b/library/std/src/fs.rs
@@ -744,6 +744,7 @@ impl OpenOptions {
/// let file = options.read(true).open("foo.txt");
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
pub fn new() -> Self {
OpenOptions(fs_imp::OpenOptions::new())
}
@@ -2184,6 +2185,7 @@ impl DirBuilder {
/// let builder = DirBuilder::new();
/// ```
#[stable(feature = "dir_builder", since = "1.6.0")]
+ #[must_use]
pub fn new() -> DirBuilder {
DirBuilder { inner: fs_imp::DirBuilder::new(), recursive: false }
}
diff --git a/library/std/src/io/error.rs b/library/std/src/io/error.rs
index 51666c0a3c7f1..57b5c28430f1e 100644
--- a/library/std/src/io/error.rs
+++ b/library/std/src/io/error.rs
@@ -473,6 +473,7 @@ impl Error {
/// # }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
#[inline]
pub fn from_raw_os_error(code: i32) -> Error {
Error { repr: Repr::Os(code) }
diff --git a/library/std/src/io/mod.rs b/library/std/src/io/mod.rs
index 8c71138aa231d..abe29ba0f7caa 100644
--- a/library/std/src/io/mod.rs
+++ b/library/std/src/io/mod.rs
@@ -1206,6 +1206,7 @@ impl<'a> IoSlice<'a> {
///
/// Panics on Windows if the slice is larger than 4GB.
#[stable(feature = "iovec", since = "1.36.0")]
+ #[must_use]
#[inline]
pub fn new(buf: &'a [u8]) -> IoSlice<'a> {
IoSlice(sys::io::IoSlice::new(buf))
diff --git a/library/std/src/lazy.rs b/library/std/src/lazy.rs
index 5afdb799f0c74..d7450962359df 100644
--- a/library/std/src/lazy.rs
+++ b/library/std/src/lazy.rs
@@ -171,6 +171,7 @@ impl<T: Eq> Eq for SyncOnceCell<T> {}
impl<T> SyncOnceCell<T> {
/// Creates a new empty cell.
#[unstable(feature = "once_cell", issue = "74465")]
+ #[must_use]
pub const fn new() -> SyncOnceCell<T> {
SyncOnceCell {
once: Once::new(),
diff --git a/library/std/src/net/addr.rs b/library/std/src/net/addr.rs
index f4ebcd53a25f7..cd2007cc2cb42 100644
--- a/library/std/src/net/addr.rs
+++ b/library/std/src/net/addr.rs
@@ -131,6 +131,7 @@ impl SocketAddr {
/// assert_eq!(socket.port(), 8080);
/// ```
#[stable(feature = "ip_addr", since = "1.7.0")]
+ #[must_use]
pub fn new(ip: IpAddr, port: u16) -> SocketAddr {
match ip {
IpAddr::V4(a) => SocketAddr::V4(SocketAddrV4::new(a, port)),
@@ -272,6 +273,7 @@ impl SocketAddrV4 {
/// let socket = SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 8080);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
pub fn new(ip: Ipv4Addr, port: u16) -> SocketAddrV4 {
SocketAddrV4 {
inner: c::sockaddr_in {
@@ -368,6 +370,7 @@ impl SocketAddrV6 {
/// let socket = SocketAddrV6::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1), 8080, 0, 0);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
pub fn new(ip: Ipv6Addr, port: u16, flowinfo: u32, scope_id: u32) -> SocketAddrV6 {
SocketAddrV6 {
inner: c::sockaddr_in6 {
diff --git a/library/std/src/net/ip.rs b/library/std/src/net/ip.rs
index c05a32742ba1e..99922eef61f10 100644
--- a/library/std/src/net/ip.rs
+++ b/library/std/src/net/ip.rs
@@ -442,6 +442,7 @@ impl Ipv4Addr {
/// ```
#[rustc_const_stable(feature = "const_ipv4", since = "1.32.0")]
#[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
#[inline]
pub const fn new(a: u8, b: u8, c: u8, d: u8) -> Ipv4Addr {
// `s_addr` is stored as BE on all machine and the array is in BE order.
@@ -1192,6 +1193,7 @@ impl Ipv6Addr {
/// ```
#[rustc_const_stable(feature = "const_ipv6", since = "1.32.0")]
#[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
#[inline]
pub const fn new(a: u16, b: u16, c: u16, d: u16, e: u16, f: u16, g: u16, h: u16) -> Ipv6Addr {
let addr16 = [
diff --git a/library/std/src/os/unix/fs.rs b/library/std/src/os/unix/fs.rs
index 0284a428b5d74..631944ca259bf 100644
--- a/library/std/src/os/unix/fs.rs
+++ b/library/std/src/os/unix/fs.rs
@@ -54,6 +54,20 @@ pub trait FileExt {
#[stable(feature = "file_offset", since = "1.15.0")]
fn read_at(&self, buf: &mut [u8], offset: u64) -> io::Result<usize>;
+ /// Like `read_at`, except that it reads into a slice of buffers.
+ ///
+ /// Data is copied to fill each buffer in order, with the final buffer
+ /// written to possibly being only partially filled. This method must behave
+ /// equivalently to a single call to read with concatenated buffers.
+ #[unstable(feature = "unix_file_vectored_at", issue = "89517")]
+ fn read_vectored_at(
+ &mut self,
+ bufs: &mut [io::IoSliceMut<'_>],
+ offset: u64,
+ ) -> io::Result<usize> {
+ io::default_read_vectored(|b| self.read_at(b, offset), bufs)
+ }
+
/// Reads the exact number of byte required to fill `buf` from the given offset.
///
/// The offset is relative to the start of the file and thus independent
@@ -155,6 +169,16 @@ pub trait FileExt {
#[stable(feature = "file_offset", since = "1.15.0")]
fn write_at(&self, buf: &[u8], offset: u64) -> io::Result<usize>;
+ /// Like `write_at`, except that it writes from a slice of buffers.
+ ///
+ /// Data is copied from each buffer in order, with the final buffer read
+ /// from possibly being only partially consumed. This method must behave as
+ /// a call to `write_at` with the buffers concatenated would.
+ #[unstable(feature = "unix_file_vectored_at", issue = "89517")]
+ fn write_vectored_at(&mut self, bufs: &[io::IoSlice<'_>], offset: u64) -> io::Result<usize> {
+ io::default_write_vectored(|b| self.write_at(b, offset), bufs)
+ }
+
/// Attempts to write an entire buffer starting from a given offset.
///
/// The offset is relative to the start of the file and thus independent
@@ -218,9 +242,19 @@ impl FileExt for fs::File {
fn read_at(&self, buf: &mut [u8], offset: u64) -> io::Result<usize> {
self.as_inner().read_at(buf, offset)
}
+ fn read_vectored_at(
+ &mut self,
+ bufs: &mut [io::IoSliceMut<'_>],
+ offset: u64,
+ ) -> io::Result<usize> {
+ self.as_inner().read_vectored_at(bufs, offset)
+ }
fn write_at(&self, buf: &[u8], offset: u64) -> io::Result<usize> {
self.as_inner().write_at(buf, offset)
}
+ fn write_vectored_at(&mut self, bufs: &[io::IoSlice<'_>], offset: u64) -> io::Result<usize> {
+ self.as_inner().write_vectored_at(bufs, offset)
+ }
}
/// Unix-specific extensions to [`fs::Permissions`].
diff --git a/library/std/src/os/unix/net/ancillary.rs b/library/std/src/os/unix/net/ancillary.rs
index 1f9d42812ecc7..57bb61903c147 100644
--- a/library/std/src/os/unix/net/ancillary.rs
+++ b/library/std/src/os/unix/net/ancillary.rs
@@ -189,6 +189,7 @@ impl SocketCred {
///
/// PID, UID and GID is set to 0.
#[unstable(feature = "unix_socket_ancillary_data", issue = "76915")]
+ #[must_use]
pub fn new() -> SocketCred {
SocketCred(libc::ucred { pid: 0, uid: 0, gid: 0 })
}
diff --git a/library/std/src/path.rs b/library/std/src/path.rs
index a45ecf6ea8c63..c5476c3d5267b 100644
--- a/library/std/src/path.rs
+++ b/library/std/src/path.rs
@@ -1145,6 +1145,7 @@ impl PathBuf {
/// let path = PathBuf::new();
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
#[inline]
pub fn new() -> PathBuf {
PathBuf { inner: OsString::new() }
@@ -1169,6 +1170,7 @@ impl PathBuf {
///
/// [`with_capacity`]: OsString::with_capacity
#[stable(feature = "path_buf_capacity", since = "1.44.0")]
+ #[must_use]
#[inline]
pub fn with_capacity(capacity: usize) -> PathBuf {
PathBuf { inner: OsString::with_capacity(capacity) }
diff --git a/library/std/src/sync/barrier.rs b/library/std/src/sync/barrier.rs
index a17b82f82e8c2..0e28a2d166f13 100644
--- a/library/std/src/sync/barrier.rs
+++ b/library/std/src/sync/barrier.rs
@@ -80,6 +80,7 @@ impl Barrier {
/// let barrier = Barrier::new(10);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
pub fn new(n: usize) -> Barrier {
Barrier {
lock: Mutex::new(BarrierState { count: 0, generation_id: 0 }),
diff --git a/library/std/src/sync/condvar.rs b/library/std/src/sync/condvar.rs
index 00a4afc570519..d8aca9651b867 100644
--- a/library/std/src/sync/condvar.rs
+++ b/library/std/src/sync/condvar.rs
@@ -121,6 +121,7 @@ impl Condvar {
/// let condvar = Condvar::new();
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
pub fn new() -> Condvar {
Condvar { inner: sys::Condvar::new() }
}
diff --git a/library/std/src/sync/once.rs b/library/std/src/sync/once.rs
index a2e935a0cebc4..1710c0053934a 100644
--- a/library/std/src/sync/once.rs
+++ b/library/std/src/sync/once.rs
@@ -186,6 +186,7 @@ impl Once {
#[inline]
#[stable(feature = "once_new", since = "1.2.0")]
#[rustc_const_stable(feature = "const_once_new", since = "1.32.0")]
+ #[must_use]
pub const fn new() -> Once {
Once { state_and_queue: AtomicUsize::new(INCOMPLETE), _marker: marker::PhantomData }
}
diff --git a/library/std/src/sys/unix/fd.rs b/library/std/src/sys/unix/fd.rs
index 0956726084e02..3b2401db81d9e 100644
--- a/library/std/src/sys/unix/fd.rs
+++ b/library/std/src/sys/unix/fd.rs
@@ -76,7 +76,7 @@ impl FileDesc {
let ret = cvt(unsafe {
libc::readv(
self.as_raw_fd(),
- bufs.as_ptr() as *const libc::iovec,
+ bufs.as_mut_ptr() as *mut libc::iovec as *const libc::iovec,
cmp::min(bufs.len(), max_iov()) as c_int,
)
})?;
@@ -85,7 +85,7 @@ impl FileDesc {
#[cfg(target_os = "espidf")]
pub fn read_vectored(&self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
- return crate::io::default_read_vectored(|b| self.read(b), bufs);
+ io::default_read_vectored(|b| self.read(b), bufs)
}
#[inline]
@@ -127,6 +127,24 @@ impl FileDesc {
}
}
+ #[cfg(not(target_os = "espidf"))]
+ pub fn read_vectored_at(&self, bufs: &mut [IoSliceMut<'_>], offset: u64) -> io::Result<usize> {
+ let ret = cvt(unsafe {
+ libc::preadv(
+ self.as_raw_fd(),
+ bufs.as_mut_ptr() as *mut libc::iovec as *const libc::iovec,
+ cmp::min(bufs.len(), max_iov()) as c_int,
+ offset as _,
+ )
+ })?;
+ Ok(ret as usize)
+ }
+
+ #[cfg(target_os = "espidf")]
+ pub fn read_vectored_at(&self, bufs: &mut [IoSliceMut<'_>], offset: u64) -> io::Result<usize> {
+ io::default_read_vectored(|b| self.read_at(b, offset), bufs)
+ }
+
pub fn write(&self, buf: &[u8]) -> io::Result<usize> {
let ret = cvt(unsafe {
libc::write(
@@ -152,7 +170,7 @@ impl FileDesc {
#[cfg(target_os = "espidf")]
pub fn write_vectored(&self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
- return crate::io::default_write_vectored(|b| self.write(b), bufs);
+ io::default_write_vectored(|b| self.write(b), bufs)
}
#[inline]
@@ -189,6 +207,24 @@ impl FileDesc {
}
}
+ #[cfg(not(target_os = "espidf"))]
+ pub fn write_vectored_at(&self, bufs: &[IoSlice<'_>], offset: u64) -> io::Result<usize> {
+ let ret = cvt(unsafe {
+ libc::pwritev(
+ self.as_raw_fd(),
+ bufs.as_ptr() as *const libc::iovec,
+ cmp::min(bufs.len(), max_iov()) as c_int,
+ offset as _,
+ )
+ })?;
+ Ok(ret as usize)
+ }
+
+ #[cfg(target_os = "espidf")]
+ pub fn write_vectored_at(&self, bufs: &[IoSlice<'_>], offset: u64) -> io::Result<usize> {
+ io::default_write_vectored(|b| self.write_at(b, offset), bufs)
+ }
+
#[cfg(target_os = "linux")]
pub fn get_cloexec(&self) -> io::Result<bool> {
unsafe { Ok((cvt(libc::fcntl(self.as_raw_fd(), libc::F_GETFD))? & libc::FD_CLOEXEC) != 0) }
diff --git a/library/std/src/sys/unix/fs.rs b/library/std/src/sys/unix/fs.rs
index a4fff9b2e6473..3db62ba6465b5 100644
--- a/library/std/src/sys/unix/fs.rs
+++ b/library/std/src/sys/unix/fs.rs
@@ -864,6 +864,10 @@ impl File {
self.0.read_at(buf, offset)
}
+ pub fn read_vectored_at(&self, bufs: &mut [IoSliceMut<'_>], offset: u64) -> io::Result<usize> {
+ self.0.read_vectored_at(bufs, offset)
+ }
+
pub fn write(&self, buf: &[u8]) -> io::Result<usize> {
self.0.write(buf)
}
@@ -881,6 +885,10 @@ impl File {
self.0.write_at(buf, offset)
}
+ pub fn write_vectored_at(&self, bufs: &[IoSlice<'_>], offset: u64) -> io::Result<usize> {
+ self.0.write_vectored_at(bufs, offset)
+ }
+
pub fn flush(&self) -> io::Result<()> {
Ok(())
}
diff --git a/src/bootstrap/bootstrap.py b/src/bootstrap/bootstrap.py
index 05d7b0f611f72..817850b1ec7eb 100644
--- a/src/bootstrap/bootstrap.py
+++ b/src/bootstrap/bootstrap.py
@@ -460,7 +460,7 @@ def download_toolchain(self, stage0=True, rustc_channel=None):
# LLVM more often than necessary.
#
# This git command finds that commit SHA, looking for bors-authored
- # merges that modified src/llvm-project or other relevant version
+ # commits that modified src/llvm-project or other relevant version
# stamp files.
#
# This works even in a repository that has not yet initialized
@@ -470,7 +470,7 @@ def download_toolchain(self, stage0=True, rustc_channel=None):
]).decode(sys.getdefaultencoding()).strip()
llvm_sha = subprocess.check_output([
"git", "rev-list", "--author=bors@rust-lang.org", "-n1",
- "--merges", "--first-parent", "HEAD",
+ "--first-parent", "HEAD",
"--",
"{}/src/llvm-project".format(top_level),
"{}/src/bootstrap/download-ci-llvm-stamp".format(top_level),
@@ -540,6 +540,12 @@ def _download_component_helper(
unpack(tarball, tarball_suffix, self.bin_root(stage0), match=pattern, verbose=self.verbose)
def _download_ci_llvm(self, llvm_sha, llvm_assertions):
+ if not llvm_sha:
+ print("error: could not find commit hash for downloading LLVM")
+ print("help: maybe your repository history is too shallow?")
+ print("help: consider disabling `download-ci-llvm`")
+ print("help: or fetch enough history to include one upstream commit")
+ exit(1)
cache_prefix = "llvm-{}-{}".format(llvm_sha, llvm_assertions)
cache_dst = os.path.join(self.build_dir, "cache")
rustc_cache = os.path.join(cache_dst, cache_prefix)
@@ -685,9 +691,15 @@ def maybe_download_ci_toolchain(self):
# Only commits merged by bors will have CI artifacts.
merge_base = [
"git", "rev-list", "--author=bors@rust-lang.org", "-n1",
- "--merges", "--first-parent", "HEAD"
+ "--first-parent", "HEAD"
]
commit = subprocess.check_output(merge_base, universal_newlines=True).strip()
+ if not commit:
+ print("error: could not find commit hash for downloading rustc")
+ print("help: maybe your repository history is too shallow?")
+ print("help: consider disabling `download-rustc`")
+ print("help: or fetch enough history to include one upstream commit")
+ exit(1)
# Warn if there were changes to the compiler or standard library since the ancestor commit.
status = subprocess.call(["git", "diff-index", "--quiet", commit, "--", compiler, library])
diff --git a/src/test/ui/weak-new-uninhabited-issue-48493.rs b/src/test/ui/weak-new-uninhabited-issue-48493.rs
index 644fc8c248375..39fbf3c9eb4e2 100644
--- a/src/test/ui/weak-new-uninhabited-issue-48493.rs
+++ b/src/test/ui/weak-new-uninhabited-issue-48493.rs
@@ -2,6 +2,6 @@
fn main() {
enum Void {}
- std::rc::Weak::<Void>::new();
- std::sync::Weak::<Void>::new();
+ let _ = std::rc::Weak::<Void>::new();
+ let _ = std::sync::Weak::<Void>::new();
}
diff --git a/src/tools/rust-analyzer b/src/tools/rust-analyzer
index 4b7675fcc30d3..ed4b312fa777e 160000
--- a/src/tools/rust-analyzer
+++ b/src/tools/rust-analyzer
@@ -1 +1 @@
-Subproject commit 4b7675fcc30d3e2c05eafc68a5724db66b58142c
+Subproject commit ed4b312fa777ebb39ba1348fe3df574c441a485e