diff options
Diffstat (limited to '')
| -rw-r--r-- | library/core/src/intrinsics.rs | 530 |
1 files changed, 168 insertions, 362 deletions
diff --git a/library/core/src/intrinsics.rs b/library/core/src/intrinsics.rs index cabc5017f..1dc79afe8 100644 --- a/library/core/src/intrinsics.rs +++ b/library/core/src/intrinsics.rs @@ -54,7 +54,7 @@ )] #![allow(missing_docs)] -use crate::marker::{Destruct, DiscriminantKind}; +use crate::marker::DiscriminantKind; use crate::mem; // These imports are used for simplifying intra-doc links @@ -63,7 +63,7 @@ use crate::mem; use crate::sync::atomic::{self, AtomicBool, AtomicI32, AtomicIsize, AtomicU32, Ordering}; #[stable(feature = "drop_in_place", since = "1.8.0")] -#[cfg_attr(not(bootstrap), rustc_allowed_through_unstable_modules)] +#[rustc_allowed_through_unstable_modules] #[deprecated(note = "no longer an intrinsic - use `ptr::drop_in_place` directly", since = "1.52.0")] #[inline] pub unsafe fn drop_in_place<T: ?Sized>(to_drop: *mut T) { @@ -71,214 +71,6 @@ pub unsafe fn drop_in_place<T: ?Sized>(to_drop: *mut T) { unsafe { crate::ptr::drop_in_place(to_drop) } } -// These have been renamed. -#[cfg(bootstrap)] -extern "rust-intrinsic" { - pub fn atomic_cxchg<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool); - pub fn atomic_cxchg_acq<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool); - pub fn atomic_cxchg_rel<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool); - pub fn atomic_cxchg_acqrel<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool); - pub fn atomic_cxchg_relaxed<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool); - pub fn atomic_cxchg_failrelaxed<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool); - pub fn atomic_cxchg_failacq<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool); - pub fn atomic_cxchg_acq_failrelaxed<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool); - pub fn atomic_cxchg_acqrel_failrelaxed<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool); - pub fn atomic_cxchgweak<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool); - pub fn atomic_cxchgweak_acq<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool); - pub fn atomic_cxchgweak_rel<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool); - pub fn atomic_cxchgweak_acqrel<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool); - pub fn atomic_cxchgweak_relaxed<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool); - pub fn atomic_cxchgweak_failrelaxed<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool); - pub fn atomic_cxchgweak_failacq<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool); - pub fn atomic_cxchgweak_acq_failrelaxed<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool); - pub fn atomic_cxchgweak_acqrel_failrelaxed<T: Copy>(dst: *mut T, old: T, src: T) -> (T, bool); - pub fn atomic_load<T: Copy>(src: *const T) -> T; - pub fn atomic_load_acq<T: Copy>(src: *const T) -> T; - pub fn atomic_load_relaxed<T: Copy>(src: *const T) -> T; - pub fn atomic_load_unordered<T: Copy>(src: *const T) -> T; - pub fn atomic_store<T: Copy>(dst: *mut T, val: T); - pub fn atomic_store_rel<T: Copy>(dst: *mut T, val: T); - pub fn atomic_store_relaxed<T: Copy>(dst: *mut T, val: T); - pub fn atomic_store_unordered<T: Copy>(dst: *mut T, val: T); - pub fn atomic_xchg<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_xchg_acq<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_xchg_rel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_xchg_acqrel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_xchg_relaxed<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_xadd<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_xadd_acq<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_xadd_rel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_xadd_acqrel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_xadd_relaxed<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_xsub<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_xsub_acq<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_xsub_rel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_xsub_acqrel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_xsub_relaxed<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_and<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_and_acq<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_and_rel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_and_acqrel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_and_relaxed<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_nand<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_nand_acq<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_nand_rel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_nand_acqrel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_nand_relaxed<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_or<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_or_acq<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_or_rel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_or_acqrel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_or_relaxed<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_xor<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_xor_acq<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_xor_rel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_xor_acqrel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_xor_relaxed<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_max<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_max_acq<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_max_rel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_max_acqrel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_max_relaxed<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_min<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_min_acq<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_min_rel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_min_acqrel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_min_relaxed<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_umin<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_umin_acq<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_umin_rel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_umin_acqrel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_umin_relaxed<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_umax<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_umax_acq<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_umax_rel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_umax_acqrel<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_umax_relaxed<T: Copy>(dst: *mut T, src: T) -> T; - pub fn atomic_fence(); - pub fn atomic_fence_acq(); - pub fn atomic_fence_rel(); - pub fn atomic_fence_acqrel(); - pub fn atomic_singlethreadfence(); - pub fn atomic_singlethreadfence_acq(); - pub fn atomic_singlethreadfence_rel(); - pub fn atomic_singlethreadfence_acqrel(); -} - -// These have been renamed. -#[cfg(bootstrap)] -mod atomics { - pub use super::atomic_cxchg as atomic_cxchg_seqcst_seqcst; - pub use super::atomic_cxchg_acq as atomic_cxchg_acquire_acquire; - pub use super::atomic_cxchg_acq_failrelaxed as atomic_cxchg_acquire_relaxed; - pub use super::atomic_cxchg_acqrel as atomic_cxchg_acqrel_acquire; - pub use super::atomic_cxchg_acqrel_failrelaxed as atomic_cxchg_acqrel_relaxed; - pub use super::atomic_cxchg_failacq as atomic_cxchg_seqcst_acquire; - pub use super::atomic_cxchg_failrelaxed as atomic_cxchg_seqcst_relaxed; - pub use super::atomic_cxchg_rel as atomic_cxchg_release_relaxed; - pub use super::atomic_cxchg_relaxed as atomic_cxchg_relaxed_relaxed; - - pub use super::atomic_cxchgweak as atomic_cxchgweak_seqcst_seqcst; - pub use super::atomic_cxchgweak_acq as atomic_cxchgweak_acquire_acquire; - pub use super::atomic_cxchgweak_acq_failrelaxed as atomic_cxchgweak_acquire_relaxed; - pub use super::atomic_cxchgweak_acqrel as atomic_cxchgweak_acqrel_acquire; - pub use super::atomic_cxchgweak_acqrel_failrelaxed as atomic_cxchgweak_acqrel_relaxed; - pub use super::atomic_cxchgweak_failacq as atomic_cxchgweak_seqcst_acquire; - pub use super::atomic_cxchgweak_failrelaxed as atomic_cxchgweak_seqcst_relaxed; - pub use super::atomic_cxchgweak_rel as atomic_cxchgweak_release_relaxed; - pub use super::atomic_cxchgweak_relaxed as atomic_cxchgweak_relaxed_relaxed; - - pub use super::atomic_load as atomic_load_seqcst; - pub use super::atomic_load_acq as atomic_load_acquire; - pub use super::atomic_load_relaxed; - pub use super::atomic_load_unordered; - - pub use super::atomic_store as atomic_store_seqcst; - pub use super::atomic_store_rel as atomic_store_release; - pub use super::atomic_store_relaxed; - pub use super::atomic_store_unordered; - - pub use super::atomic_xchg as atomic_xchg_seqcst; - pub use super::atomic_xchg_acq as atomic_xchg_acquire; - pub use super::atomic_xchg_acqrel; - pub use super::atomic_xchg_rel as atomic_xchg_release; - pub use super::atomic_xchg_relaxed; - - pub use super::atomic_xadd as atomic_xadd_seqcst; - pub use super::atomic_xadd_acq as atomic_xadd_acquire; - pub use super::atomic_xadd_acqrel; - pub use super::atomic_xadd_rel as atomic_xadd_release; - pub use super::atomic_xadd_relaxed; - - pub use super::atomic_xsub as atomic_xsub_seqcst; - pub use super::atomic_xsub_acq as atomic_xsub_acquire; - pub use super::atomic_xsub_acqrel; - pub use super::atomic_xsub_rel as atomic_xsub_release; - pub use super::atomic_xsub_relaxed; - - pub use super::atomic_and as atomic_and_seqcst; - pub use super::atomic_and_acq as atomic_and_acquire; - pub use super::atomic_and_acqrel; - pub use super::atomic_and_rel as atomic_and_release; - pub use super::atomic_and_relaxed; - - pub use super::atomic_nand as atomic_nand_seqcst; - pub use super::atomic_nand_acq as atomic_nand_acquire; - pub use super::atomic_nand_acqrel; - pub use super::atomic_nand_rel as atomic_nand_release; - pub use super::atomic_nand_relaxed; - - pub use super::atomic_or as atomic_or_seqcst; - pub use super::atomic_or_acq as atomic_or_acquire; - pub use super::atomic_or_acqrel; - pub use super::atomic_or_rel as atomic_or_release; - pub use super::atomic_or_relaxed; - - pub use super::atomic_xor as atomic_xor_seqcst; - pub use super::atomic_xor_acq as atomic_xor_acquire; - pub use super::atomic_xor_acqrel; - pub use super::atomic_xor_rel as atomic_xor_release; - pub use super::atomic_xor_relaxed; - - pub use super::atomic_max as atomic_max_seqcst; - pub use super::atomic_max_acq as atomic_max_acquire; - pub use super::atomic_max_acqrel; - pub use super::atomic_max_rel as atomic_max_release; - pub use super::atomic_max_relaxed; - - pub use super::atomic_min as atomic_min_seqcst; - pub use super::atomic_min_acq as atomic_min_acquire; - pub use super::atomic_min_acqrel; - pub use super::atomic_min_rel as atomic_min_release; - pub use super::atomic_min_relaxed; - - pub use super::atomic_umin as atomic_umin_seqcst; - pub use super::atomic_umin_acq as atomic_umin_acquire; - pub use super::atomic_umin_acqrel; - pub use super::atomic_umin_rel as atomic_umin_release; - pub use super::atomic_umin_relaxed; - - pub use super::atomic_umax as atomic_umax_seqcst; - pub use super::atomic_umax_acq as atomic_umax_acquire; - pub use super::atomic_umax_acqrel; - pub use super::atomic_umax_rel as atomic_umax_release; - pub use super::atomic_umax_relaxed; - - pub use super::atomic_fence as atomic_fence_seqcst; - pub use super::atomic_fence_acq as atomic_fence_acquire; - pub use super::atomic_fence_acqrel; - pub use super::atomic_fence_rel as atomic_fence_release; - - pub use super::atomic_singlethreadfence as atomic_singlethreadfence_seqcst; - pub use super::atomic_singlethreadfence_acq as atomic_singlethreadfence_acquire; - pub use super::atomic_singlethreadfence_acqrel; - pub use super::atomic_singlethreadfence_rel as atomic_singlethreadfence_release; -} - -#[cfg(bootstrap)] -pub use atomics::*; - -#[cfg(not(bootstrap))] extern "rust-intrinsic" { // N.B., these intrinsics take raw pointers because they mutate aliased // memory, which is not valid for either `&` or `&mut`. @@ -945,30 +737,7 @@ extern "rust-intrinsic" { /// [`atomic::compiler_fence`] by passing [`Ordering::AcqRel`] /// as the `order`. pub fn atomic_singlethreadfence_acqrel(); -} - -// These have been renamed. -// -// These are the aliases for the old names. -// To be removed when stdarch and panic_unwind have been updated. -#[cfg(not(bootstrap))] -mod atomics { - pub use super::atomic_cxchg_acqrel_acquire as atomic_cxchg_acqrel; - pub use super::atomic_cxchg_acqrel_relaxed as atomic_cxchg_acqrel_failrelaxed; - pub use super::atomic_cxchg_acquire_acquire as atomic_cxchg_acq; - pub use super::atomic_cxchg_acquire_relaxed as atomic_cxchg_acq_failrelaxed; - pub use super::atomic_cxchg_relaxed_relaxed as atomic_cxchg_relaxed; - pub use super::atomic_cxchg_release_relaxed as atomic_cxchg_rel; - pub use super::atomic_cxchg_seqcst_acquire as atomic_cxchg_failacq; - pub use super::atomic_cxchg_seqcst_relaxed as atomic_cxchg_failrelaxed; - pub use super::atomic_cxchg_seqcst_seqcst as atomic_cxchg; - pub use super::atomic_store_seqcst as atomic_store; -} - -#[cfg(not(bootstrap))] -pub use atomics::*; -extern "rust-intrinsic" { /// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction /// if supported; otherwise, it is a no-op. /// Prefetches have no effect on the behavior of the program but can change its performance @@ -1019,6 +788,7 @@ extern "rust-intrinsic" { /// uninitialized at that point in the control flow. /// /// This intrinsic should not be used outside of the compiler. + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn rustc_peek<T>(_: T) -> T; /// Aborts the execution of the process. @@ -1036,6 +806,7 @@ extern "rust-intrinsic" { /// On Unix, the /// process will probably terminate with a signal like `SIGABRT`, `SIGILL`, `SIGTRAP`, `SIGSEGV` or /// `SIGBUS`. The precise behaviour is not guaranteed and not stable. + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn abort() -> !; /// Informs the optimizer that this point in the code is not reachable, @@ -1074,6 +845,7 @@ extern "rust-intrinsic" { /// /// This intrinsic does not have a stable counterpart. #[rustc_const_unstable(feature = "const_likely", issue = "none")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn likely(b: bool) -> bool; /// Hints to the compiler that branch condition is likely to be false. @@ -1088,6 +860,7 @@ extern "rust-intrinsic" { /// /// This intrinsic does not have a stable counterpart. #[rustc_const_unstable(feature = "const_likely", issue = "none")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn unlikely(b: bool) -> bool; /// Executes a breakpoint trap, for inspection by a debugger. @@ -1107,6 +880,7 @@ extern "rust-intrinsic" { /// /// The stabilized version of this intrinsic is [`core::mem::size_of`]. #[rustc_const_stable(feature = "const_size_of", since = "1.40.0")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn size_of<T>() -> usize; /// The minimum alignment of a type. @@ -1118,6 +892,7 @@ extern "rust-intrinsic" { /// /// The stabilized version of this intrinsic is [`core::mem::align_of`]. #[rustc_const_stable(feature = "const_min_align_of", since = "1.40.0")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn min_align_of<T>() -> usize; /// The preferred alignment of a type. /// @@ -1146,6 +921,7 @@ extern "rust-intrinsic" { /// /// The stabilized version of this intrinsic is [`core::any::type_name`]. #[rustc_const_unstable(feature = "const_type_name", issue = "63084")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn type_name<T: ?Sized>() -> &'static str; /// Gets an identifier which is globally unique to the specified type. This @@ -1159,6 +935,7 @@ extern "rust-intrinsic" { /// /// The stabilized version of this intrinsic is [`core::any::TypeId::of`]. #[rustc_const_unstable(feature = "const_type_id", issue = "77125")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn type_id<T: ?Sized + 'static>() -> u64; /// A guard for unsafe functions that cannot ever be executed if `T` is uninhabited: @@ -1166,6 +943,7 @@ extern "rust-intrinsic" { /// /// This intrinsic does not have a stable counterpart. #[rustc_const_stable(feature = "const_assert_type", since = "1.59.0")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn assert_inhabited<T>(); /// A guard for unsafe functions that cannot ever be executed if `T` does not permit @@ -1173,6 +951,7 @@ extern "rust-intrinsic" { /// /// This intrinsic does not have a stable counterpart. #[rustc_const_unstable(feature = "const_assert_type2", issue = "none")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn assert_zero_valid<T>(); /// A guard for unsafe functions that cannot ever be executed if `T` has invalid @@ -1180,6 +959,7 @@ extern "rust-intrinsic" { /// /// This intrinsic does not have a stable counterpart. #[rustc_const_unstable(feature = "const_assert_type2", issue = "none")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn assert_uninit_valid<T>(); /// Gets a reference to a static `Location` indicating where it was called. @@ -1191,6 +971,7 @@ extern "rust-intrinsic" { /// /// Consider using [`core::panic::Location::caller`] instead. #[rustc_const_unstable(feature = "const_caller_location", issue = "76156")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn caller_location() -> &'static crate::panic::Location<'static>; /// Moves a value out of scope without running drop glue. @@ -1203,6 +984,7 @@ extern "rust-intrinsic" { /// Therefore, implementations must not require the user to uphold /// any safety invariants. #[rustc_const_unstable(feature = "const_intrinsic_forget", issue = "none")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn forget<T: ?Sized>(_: T); /// Reinterprets the bits of a value of one type as another type. @@ -1212,14 +994,14 @@ extern "rust-intrinsic" { /// `transmute` is semantically equivalent to a bitwise move of one type /// into another. It copies the bits from the source value into the /// destination value, then forgets the original. Note that source and destination - /// are passed by-value, which means if `T` or `U` contain padding, that padding + /// are passed by-value, which means if `Src` or `Dst` contain padding, that padding /// is *not* guaranteed to be preserved by `transmute`. /// /// Both the argument and the result must be [valid](../../nomicon/what-unsafe-does.html) at /// their given type. Violating this condition leads to [undefined behavior][ub]. The compiler /// will generate code *assuming that you, the programmer, ensure that there will never be /// undefined behavior*. It is therefore your responsibility to guarantee that every value - /// passed to `transmute` is valid at both types `T` and `U`. Failing to uphold this condition + /// passed to `transmute` is valid at both types `Src` and `Dst`. Failing to uphold this condition /// may lead to unexpected and unstable compilation results. This makes `transmute` **incredibly /// unsafe**. `transmute` should be the absolute last resort. /// @@ -1230,7 +1012,7 @@ extern "rust-intrinsic" { /// /// Because `transmute` is a by-value operation, alignment of the *transmuted values /// themselves* is not a concern. As with any other function, the compiler already ensures - /// both `T` and `U` are properly aligned. However, when transmuting values that *point + /// both `Src` and `Dst` are properly aligned. However, when transmuting values that *point /// elsewhere* (such as pointers, references, boxes…), the caller has to ensure proper /// alignment of the pointed-to values. /// @@ -1313,7 +1095,7 @@ extern "rust-intrinsic" { /// Note that using `transmute` to turn a pointer to a `usize` is (as noted above) [undefined /// behavior][ub] in `const` contexts. Also outside of consts, this operation might not behave /// as expected -- this is touching on many unspecified aspects of the Rust memory model. - /// Depending on what the code is doing, the following alternatives are preferrable to + /// Depending on what the code is doing, the following alternatives are preferable to /// pointer-to-integer transmutation: /// - If the code just wants to store data of arbitrary type in some buffer and needs to pick a /// type for that buffer, it can use [`MaybeUninit`][mem::MaybeUninit]. @@ -1463,10 +1245,10 @@ extern "rust-intrinsic" { /// } /// ``` #[stable(feature = "rust1", since = "1.0.0")] - #[cfg_attr(not(bootstrap), rustc_allowed_through_unstable_modules)] + #[rustc_allowed_through_unstable_modules] #[rustc_const_stable(feature = "const_transmute", since = "1.56.0")] #[rustc_diagnostic_item = "transmute"] - pub fn transmute<T, U>(e: T) -> U; + pub fn transmute<Src, Dst>(src: Src) -> Dst; /// Returns `true` if the actual type given as `T` requires drop /// glue; returns `false` if the actual type provided for `T` @@ -1482,6 +1264,7 @@ extern "rust-intrinsic" { /// /// The stabilized version of this intrinsic is [`mem::needs_drop`](crate::mem::needs_drop). #[rustc_const_stable(feature = "const_needs_drop", since = "1.40.0")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn needs_drop<T: ?Sized>() -> bool; /// Calculates the offset from a pointer. @@ -1518,6 +1301,17 @@ extern "rust-intrinsic" { #[rustc_const_stable(feature = "const_ptr_offset", since = "1.61.0")] pub fn arith_offset<T>(dst: *const T, offset: isize) -> *const T; + /// Masks out bits of the pointer according to a mask. + /// + /// Note that, unlike most intrinsics, this is safe to call; + /// it does not require an `unsafe` block. + /// Therefore, implementations must not require the user to uphold + /// any safety invariants. + /// + /// Consider using [`pointer::mask`] instead. + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] + pub fn ptr_mask<T>(ptr: *const T, mask: usize) -> *const T; + /// Equivalent to the appropriate `llvm.memcpy.p0i8.0i8.*` intrinsic, with /// a size of `count` * `size_of::<T>()` and an alignment of /// `min_align_of::<T>()` @@ -1707,6 +1501,7 @@ extern "rust-intrinsic" { /// /// The stabilized version of this intrinsic is /// [`f32::min`] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn minnumf32(x: f32, y: f32) -> f32; /// Returns the minimum of two `f64` values. /// @@ -1717,6 +1512,7 @@ extern "rust-intrinsic" { /// /// The stabilized version of this intrinsic is /// [`f64::min`] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn minnumf64(x: f64, y: f64) -> f64; /// Returns the maximum of two `f32` values. /// @@ -1727,6 +1523,7 @@ extern "rust-intrinsic" { /// /// The stabilized version of this intrinsic is /// [`f32::max`] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn maxnumf32(x: f32, y: f32) -> f32; /// Returns the maximum of two `f64` values. /// @@ -1737,6 +1534,7 @@ extern "rust-intrinsic" { /// /// The stabilized version of this intrinsic is /// [`f64::max`] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn maxnumf64(x: f64, y: f64) -> f64; /// Copies the sign from `y` to `x` for `f32` values. @@ -1857,6 +1655,7 @@ extern "rust-intrinsic" { /// primitives via the `count_ones` method. For example, /// [`u32::count_ones`] #[rustc_const_stable(feature = "const_ctpop", since = "1.40.0")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn ctpop<T: Copy>(x: T) -> T; /// Returns the number of leading unset bits (zeroes) in an integer type `T`. @@ -1894,6 +1693,7 @@ extern "rust-intrinsic" { /// assert_eq!(num_leading, 16); /// ``` #[rustc_const_stable(feature = "const_ctlz", since = "1.40.0")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn ctlz<T: Copy>(x: T) -> T; /// Like `ctlz`, but extra-unsafe as it returns `undef` when @@ -1950,6 +1750,7 @@ extern "rust-intrinsic" { /// assert_eq!(num_trailing, 16); /// ``` #[rustc_const_stable(feature = "const_cttz", since = "1.40.0")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn cttz<T: Copy>(x: T) -> T; /// Like `cttz`, but extra-unsafe as it returns `undef` when @@ -1982,6 +1783,7 @@ extern "rust-intrinsic" { /// primitives via the `swap_bytes` method. For example, /// [`u32::swap_bytes`] #[rustc_const_stable(feature = "const_bswap", since = "1.40.0")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn bswap<T: Copy>(x: T) -> T; /// Reverses the bits in an integer type `T`. @@ -1995,6 +1797,7 @@ extern "rust-intrinsic" { /// primitives via the `reverse_bits` method. For example, /// [`u32::reverse_bits`] #[rustc_const_stable(feature = "const_bitreverse", since = "1.40.0")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn bitreverse<T: Copy>(x: T) -> T; /// Performs checked integer addition. @@ -2008,6 +1811,7 @@ extern "rust-intrinsic" { /// primitives via the `overflowing_add` method. For example, /// [`u32::overflowing_add`] #[rustc_const_stable(feature = "const_int_overflow", since = "1.40.0")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn add_with_overflow<T: Copy>(x: T, y: T) -> (T, bool); /// Performs checked integer subtraction @@ -2021,6 +1825,7 @@ extern "rust-intrinsic" { /// primitives via the `overflowing_sub` method. For example, /// [`u32::overflowing_sub`] #[rustc_const_stable(feature = "const_int_overflow", since = "1.40.0")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn sub_with_overflow<T: Copy>(x: T, y: T) -> (T, bool); /// Performs checked integer multiplication @@ -2034,6 +1839,7 @@ extern "rust-intrinsic" { /// primitives via the `overflowing_mul` method. For example, /// [`u32::overflowing_mul`] #[rustc_const_stable(feature = "const_int_overflow", since = "1.40.0")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn mul_with_overflow<T: Copy>(x: T, y: T) -> (T, bool); /// Performs an exact division, resulting in undefined behavior where @@ -2108,6 +1914,7 @@ extern "rust-intrinsic" { /// primitives via the `rotate_left` method. For example, /// [`u32::rotate_left`] #[rustc_const_stable(feature = "const_int_rotate", since = "1.40.0")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn rotate_left<T: Copy>(x: T, y: T) -> T; /// Performs rotate right. @@ -2121,6 +1928,7 @@ extern "rust-intrinsic" { /// primitives via the `rotate_right` method. For example, /// [`u32::rotate_right`] #[rustc_const_stable(feature = "const_int_rotate", since = "1.40.0")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn rotate_right<T: Copy>(x: T, y: T) -> T; /// Returns (a + b) mod 2<sup>N</sup>, where N is the width of T in bits. @@ -2134,6 +1942,7 @@ extern "rust-intrinsic" { /// primitives via the `wrapping_add` method. For example, /// [`u32::wrapping_add`] #[rustc_const_stable(feature = "const_int_wrapping", since = "1.40.0")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn wrapping_add<T: Copy>(a: T, b: T) -> T; /// Returns (a - b) mod 2<sup>N</sup>, where N is the width of T in bits. /// @@ -2146,6 +1955,7 @@ extern "rust-intrinsic" { /// primitives via the `wrapping_sub` method. For example, /// [`u32::wrapping_sub`] #[rustc_const_stable(feature = "const_int_wrapping", since = "1.40.0")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn wrapping_sub<T: Copy>(a: T, b: T) -> T; /// Returns (a * b) mod 2<sup>N</sup>, where N is the width of T in bits. /// @@ -2158,6 +1968,7 @@ extern "rust-intrinsic" { /// primitives via the `wrapping_mul` method. For example, /// [`u32::wrapping_mul`] #[rustc_const_stable(feature = "const_int_wrapping", since = "1.40.0")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn wrapping_mul<T: Copy>(a: T, b: T) -> T; /// Computes `a + b`, saturating at numeric bounds. @@ -2171,6 +1982,7 @@ extern "rust-intrinsic" { /// primitives via the `saturating_add` method. For example, /// [`u32::saturating_add`] #[rustc_const_stable(feature = "const_int_saturating", since = "1.40.0")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn saturating_add<T: Copy>(a: T, b: T) -> T; /// Computes `a - b`, saturating at numeric bounds. /// @@ -2183,6 +1995,7 @@ extern "rust-intrinsic" { /// primitives via the `saturating_sub` method. For example, /// [`u32::saturating_sub`] #[rustc_const_stable(feature = "const_int_saturating", since = "1.40.0")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn saturating_sub<T: Copy>(a: T, b: T) -> T; /// Returns the value of the discriminant for the variant in 'v'; @@ -2195,6 +2008,7 @@ extern "rust-intrinsic" { /// /// The stabilized version of this intrinsic is [`core::mem::discriminant`]. #[rustc_const_unstable(feature = "const_discriminant", issue = "69821")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn discriminant_value<T>(v: &T) -> <T as DiscriminantKind>::Discriminant; /// Returns the number of variants of the type `T` cast to a `usize`; @@ -2207,6 +2021,7 @@ extern "rust-intrinsic" { /// /// The to-be-stabilized version of this intrinsic is [`mem::variant_count`]. #[rustc_const_unstable(feature = "variant_count", issue = "73662")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn variant_count<T>() -> usize; /// Rust's "try catch" construct which invokes the function pointer `try_fn` @@ -2223,30 +2038,25 @@ extern "rust-intrinsic" { pub fn nontemporal_store<T>(ptr: *mut T, val: T); /// See documentation of `<*const T>::offset_from` for details. - #[rustc_const_unstable(feature = "const_ptr_offset_from", issue = "92980")] + #[rustc_const_stable(feature = "const_ptr_offset_from", since = "1.65.0")] pub fn ptr_offset_from<T>(ptr: *const T, base: *const T) -> isize; /// See documentation of `<*const T>::sub_ptr` for details. - #[rustc_const_unstable(feature = "const_ptr_offset_from", issue = "92980")] + #[rustc_const_unstable(feature = "const_ptr_sub_ptr", issue = "95892")] pub fn ptr_offset_from_unsigned<T>(ptr: *const T, base: *const T) -> usize; /// See documentation of `<*const T>::guaranteed_eq` for details. + /// Returns `2` if the result is unknown. + /// Returns `1` if the pointers are guaranteed equal + /// Returns `0` if the pointers are guaranteed inequal /// /// Note that, unlike most intrinsics, this is safe to call; /// it does not require an `unsafe` block. /// Therefore, implementations must not require the user to uphold /// any safety invariants. #[rustc_const_unstable(feature = "const_raw_ptr_comparison", issue = "53020")] - pub fn ptr_guaranteed_eq<T>(ptr: *const T, other: *const T) -> bool; - - /// See documentation of `<*const T>::guaranteed_ne` for details. - /// - /// Note that, unlike most intrinsics, this is safe to call; - /// it does not require an `unsafe` block. - /// Therefore, implementations must not require the user to uphold - /// any safety invariants. - #[rustc_const_unstable(feature = "const_raw_ptr_comparison", issue = "53020")] - pub fn ptr_guaranteed_ne<T>(ptr: *const T, other: *const T) -> bool; + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] + pub fn ptr_guaranteed_cmp<T>(ptr: *const T, other: *const T) -> u8; /// Allocates a block of memory at compile time. /// At runtime, just returns a null pointer. @@ -2282,7 +2092,8 @@ extern "rust-intrinsic" { /// /// # Safety /// - /// It's UB to call this if any of the *bytes* in `*a` or `*b` are uninitialized. + /// It's UB to call this if any of the *bytes* in `*a` or `*b` are uninitialized or carry a + /// pointer value. /// Note that this is a stricter criterion than just the *values* being /// fully-initialized: if `T` has padding, it's UB to call this intrinsic. /// @@ -2295,17 +2106,74 @@ extern "rust-intrinsic" { /// /// [`std::hint::black_box`]: crate::hint::black_box #[rustc_const_unstable(feature = "const_black_box", issue = "none")] + #[cfg_attr(not(bootstrap), rustc_safe_intrinsic)] pub fn black_box<T>(dummy: T) -> T; /// `ptr` must point to a vtable. /// The intrinsic will return the size stored in that vtable. - #[cfg(not(bootstrap))] pub fn vtable_size(ptr: *const ()) -> usize; /// `ptr` must point to a vtable. /// The intrinsic will return the alignment stored in that vtable. - #[cfg(not(bootstrap))] pub fn vtable_align(ptr: *const ()) -> usize; + + /// Selects which function to call depending on the context. + /// + /// If this function is evaluated at compile-time, then a call to this + /// intrinsic will be replaced with a call to `called_in_const`. It gets + /// replaced with a call to `called_at_rt` otherwise. + /// + /// # Type Requirements + /// + /// The two functions must be both function items. They cannot be function + /// pointers or closures. The first function must be a `const fn`. + /// + /// `arg` will be the tupled arguments that will be passed to either one of + /// the two functions, therefore, both functions must accept the same type of + /// arguments. Both functions must return RET. + /// + /// # Safety + /// + /// The two functions must behave observably equivalent. Safe code in other + /// crates may assume that calling a `const fn` at compile-time and at run-time + /// produces the same result. A function that produces a different result when + /// evaluated at run-time, or has any other observable side-effects, is + /// *unsound*. + /// + /// Here is an example of how this could cause a problem: + /// ```no_run + /// #![feature(const_eval_select)] + /// #![feature(core_intrinsics)] + /// use std::hint::unreachable_unchecked; + /// use std::intrinsics::const_eval_select; + /// + /// // Crate A + /// pub const fn inconsistent() -> i32 { + /// fn runtime() -> i32 { 1 } + /// const fn compiletime() -> i32 { 2 } + /// + /// unsafe { + // // ⚠ This code violates the required equivalence of `compiletime` + /// // and `runtime`. + /// const_eval_select((), compiletime, runtime) + /// } + /// } + /// + /// // Crate B + /// const X: i32 = inconsistent(); + /// let x = inconsistent(); + /// if x != X { unsafe { unreachable_unchecked(); }} + /// ``` + /// + /// This code causes Undefined Behavior when being run, since the + /// `unreachable_unchecked` is actually being reached. The bug is in *crate A*, + /// which violates the principle that a `const fn` must behave the same at + /// compile-time and at run-time. The unsafe code in crate B is fine. + #[rustc_const_unstable(feature = "const_eval_select", issue = "none")] + pub fn const_eval_select<ARG, F, G, RET>(arg: ARG, called_in_const: F, called_at_rt: G) -> RET + where + G: FnOnce<ARG, Output = RET>, + F: FnOnce<ARG, Output = RET>; } // Some functions are defined here because they accidentally got made @@ -2316,6 +2184,11 @@ extern "rust-intrinsic" { /// Check that the preconditions of an unsafe function are followed, if debug_assertions are on, /// and only at runtime. /// +/// This macro should be called as `assert_unsafe_precondition!([Generics](name: Type) => Expression)` +/// where the names specified will be moved into the macro as captured variables, and defines an item +/// to call `const_eval_select` on. The tokens inside the square brackets are used to denote generics +/// for the function declaractions and can be omitted if there is no generics. +/// /// # Safety /// /// Invoking this macro is only sound if the following code is already UB when the passed @@ -2330,18 +2203,23 @@ extern "rust-intrinsic" { /// the occasional mistake, and this check should help them figure things out. #[allow_internal_unstable(const_eval_select)] // permit this to be called in stably-const fn macro_rules! assert_unsafe_precondition { - ($e:expr) => { + ($name:expr, $([$($tt:tt)*])?($($i:ident:$ty:ty),*$(,)?) => $e:expr) => { if cfg!(debug_assertions) { - // Use a closure so that we can capture arbitrary expressions from the invocation - let runtime = || { + // allow non_snake_case to allow capturing const generics + #[allow(non_snake_case)] + #[inline(always)] + fn runtime$(<$($tt)*>)?($($i:$ty),*) { if !$e { - // abort instead of panicking to reduce impact on code size - ::core::intrinsics::abort(); + // don't unwind to reduce impact on code size + ::core::panicking::panic_str_nounwind( + concat!("unsafe precondition(s) violated: ", $name) + ); } - }; - const fn comptime() {} + } + #[allow(non_snake_case)] + const fn comptime$(<$($tt)*>)?($(_:$ty),*) {} - ::core::intrinsics::const_eval_select((), comptime, runtime); + ::core::intrinsics::const_eval_select(($($i,)*), comptime, runtime); } }; } @@ -2350,7 +2228,17 @@ pub(crate) use assert_unsafe_precondition; /// Checks whether `ptr` is properly aligned with respect to /// `align_of::<T>()`. pub(crate) fn is_aligned_and_not_null<T>(ptr: *const T) -> bool { - !ptr.is_null() && ptr.addr() % mem::align_of::<T>() == 0 + !ptr.is_null() && ptr.is_aligned() +} + +/// Checks whether an allocation of `len` instances of `T` exceeds +/// the maximum allowed allocation size. +pub(crate) fn is_valid_allocation_size<T>(len: usize) -> bool { + let max_len = const { + let size = crate::mem::size_of::<T>(); + if size == 0 { usize::MAX } else { isize::MAX as usize / size } + }; + len <= max_len } /// Checks whether the regions of memory starting at `src` and `dst` of size @@ -2420,9 +2308,9 @@ pub(crate) fn is_nonoverlapping<T>(src: *const T, dst: *const T, count: usize) - /// dst.reserve(src_len); /// /// unsafe { -/// // The call to offset is always safe because `Vec` will never +/// // The call to add is always safe because `Vec` will never /// // allocate more than `isize::MAX` bytes. -/// let dst_ptr = dst.as_mut_ptr().offset(dst_len as isize); +/// let dst_ptr = dst.as_mut_ptr().add(dst_len); /// let src_ptr = src.as_ptr(); /// /// // Truncate `src` without dropping its contents. We do this first, @@ -2451,7 +2339,7 @@ pub(crate) fn is_nonoverlapping<T>(src: *const T, dst: *const T, count: usize) - /// [`Vec::append`]: ../../std/vec/struct.Vec.html#method.append #[doc(alias = "memcpy")] #[stable(feature = "rust1", since = "1.0.0")] -#[cfg_attr(not(bootstrap), rustc_allowed_through_unstable_modules)] +#[rustc_allowed_through_unstable_modules] #[rustc_const_stable(feature = "const_intrinsic_copy", since = "1.63.0")] #[inline] #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces @@ -2465,6 +2353,9 @@ pub const unsafe fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: us // upheld by the caller. unsafe { assert_unsafe_precondition!( + "ptr::copy_nonoverlapping requires that both pointer arguments are aligned and non-null \ + and the specified memory ranges do not overlap", + [T](src: *const T, dst: *mut T, count: usize) => is_aligned_and_not_null(src) && is_aligned_and_not_null(dst) && is_nonoverlapping(src, dst, count) @@ -2538,7 +2429,7 @@ pub const unsafe fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: us /// ``` #[doc(alias = "memmove")] #[stable(feature = "rust1", since = "1.0.0")] -#[cfg_attr(not(bootstrap), rustc_allowed_through_unstable_modules)] +#[rustc_allowed_through_unstable_modules] #[rustc_const_stable(feature = "const_intrinsic_copy", since = "1.63.0")] #[inline] #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces @@ -2550,7 +2441,11 @@ pub const unsafe fn copy<T>(src: *const T, dst: *mut T, count: usize) { // SAFETY: the safety contract for `copy` must be upheld by the caller. unsafe { - assert_unsafe_precondition!(is_aligned_and_not_null(src) && is_aligned_and_not_null(dst)); + assert_unsafe_precondition!( + "ptr::copy requires that both pointer arguments are aligned aligned and non-null", + [T](src: *const T, dst: *mut T) => + is_aligned_and_not_null(src) && is_aligned_and_not_null(dst) + ); copy(src, dst, count) } } @@ -2606,7 +2501,7 @@ pub const unsafe fn copy<T>(src: *const T, dst: *mut T, count: usize) { /// ``` #[doc(alias = "memset")] #[stable(feature = "rust1", since = "1.0.0")] -#[cfg_attr(not(bootstrap), rustc_allowed_through_unstable_modules)] +#[rustc_allowed_through_unstable_modules] #[rustc_const_unstable(feature = "const_ptr_write", issue = "86302")] #[inline] #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces @@ -2618,99 +2513,10 @@ pub const unsafe fn write_bytes<T>(dst: *mut T, val: u8, count: usize) { // SAFETY: the safety contract for `write_bytes` must be upheld by the caller. unsafe { - assert_unsafe_precondition!(is_aligned_and_not_null(dst)); + assert_unsafe_precondition!( + "ptr::write_bytes requires that the destination pointer is aligned and non-null", + [T](dst: *mut T) => is_aligned_and_not_null(dst) + ); write_bytes(dst, val, count) } } - -/// Selects which function to call depending on the context. -/// -/// If this function is evaluated at compile-time, then a call to this -/// intrinsic will be replaced with a call to `called_in_const`. It gets -/// replaced with a call to `called_at_rt` otherwise. -/// -/// # Type Requirements -/// -/// The two functions must be both function items. They cannot be function -/// pointers or closures. -/// -/// `arg` will be the arguments that will be passed to either one of the -/// two functions, therefore, both functions must accept the same type of -/// arguments. Both functions must return RET. -/// -/// # Safety -/// -/// The two functions must behave observably equivalent. Safe code in other -/// crates may assume that calling a `const fn` at compile-time and at run-time -/// produces the same result. A function that produces a different result when -/// evaluated at run-time, or has any other observable side-effects, is -/// *unsound*. -/// -/// Here is an example of how this could cause a problem: -/// ```no_run -/// #![feature(const_eval_select)] -/// #![feature(core_intrinsics)] -/// use std::hint::unreachable_unchecked; -/// use std::intrinsics::const_eval_select; -/// -/// // Crate A -/// pub const fn inconsistent() -> i32 { -/// fn runtime() -> i32 { 1 } -/// const fn compiletime() -> i32 { 2 } -/// -/// unsafe { -// // ⚠ This code violates the required equivalence of `compiletime` -/// // and `runtime`. -/// const_eval_select((), compiletime, runtime) -/// } -/// } -/// -/// // Crate B -/// const X: i32 = inconsistent(); -/// let x = inconsistent(); -/// if x != X { unsafe { unreachable_unchecked(); }} -/// ``` -/// -/// This code causes Undefined Behavior when being run, since the -/// `unreachable_unchecked` is actually being reached. The bug is in *crate A*, -/// which violates the principle that a `const fn` must behave the same at -/// compile-time and at run-time. The unsafe code in crate B is fine. -#[unstable( - feature = "const_eval_select", - issue = "none", - reason = "const_eval_select will never be stable" -)] -#[rustc_const_unstable(feature = "const_eval_select", issue = "none")] -#[lang = "const_eval_select"] -#[rustc_do_not_const_check] -#[inline] -pub const unsafe fn const_eval_select<ARG, F, G, RET>( - arg: ARG, - _called_in_const: F, - called_at_rt: G, -) -> RET -where - F: ~const FnOnce<ARG, Output = RET>, - G: FnOnce<ARG, Output = RET> + ~const Destruct, -{ - called_at_rt.call_once(arg) -} - -#[unstable( - feature = "const_eval_select", - issue = "none", - reason = "const_eval_select will never be stable" -)] -#[rustc_const_unstable(feature = "const_eval_select", issue = "none")] -#[lang = "const_eval_select_ct"] -pub const unsafe fn const_eval_select_ct<ARG, F, G, RET>( - arg: ARG, - called_in_const: F, - _called_at_rt: G, -) -> RET -where - F: ~const FnOnce<ARG, Output = RET>, - G: FnOnce<ARG, Output = RET> + ~const Destruct, -{ - called_in_const.call_once(arg) -} |