From 5e5f3341e3749f18a6d6fbb2228a9d3b42c0b280 Mon Sep 17 00:00:00 2001 From: Trevor Gross Date: Fri, 29 Sep 2023 02:40:30 -0400 Subject: [PATCH] Stabilize `const_mem_zeroed` Make `core::mem::zeroed` const stable. Newly stable API: // core::mem pub const unsafe fn zeroed() -> T; This is stabilized with `const_maybe_uninit_zeroed` since it is a simple wrapper. In order to make this possible, intrinsics `assert_zero_valid` was made const stable under `const_assert_type2`. `assert_mem_uninitialized_valid` was also made const stable since it is under the same gate. --- library/core/src/intrinsics.rs | 4 ++-- library/core/src/mem/mod.rs | 3 ++- tests/ui/consts/assert-type-intrinsics.rs | 1 - tests/ui/consts/assert-type-intrinsics.stderr | 12 ++++++------ 4 files changed, 10 insertions(+), 10 deletions(-) diff --git a/library/core/src/intrinsics.rs b/library/core/src/intrinsics.rs index 4c76662ac09..40dc323032e 100644 --- a/library/core/src/intrinsics.rs +++ b/library/core/src/intrinsics.rs @@ -1072,7 +1072,7 @@ pub unsafe fn drop_in_place(to_drop: *mut T) { /// zero-initialization: This will statically either panic, or do nothing. /// /// This intrinsic does not have a stable counterpart. - #[rustc_const_unstable(feature = "const_assert_type2", issue = "none")] + #[rustc_const_stable(feature = "const_assert_type2", since = "CURRENT_RUSTC_VERSION")] #[rustc_safe_intrinsic] #[rustc_nounwind] pub fn assert_zero_valid(); @@ -1080,7 +1080,7 @@ pub unsafe fn drop_in_place(to_drop: *mut T) { /// A guard for `std::mem::uninitialized`. This will statically either panic, or do nothing. /// /// This intrinsic does not have a stable counterpart. - #[rustc_const_unstable(feature = "const_assert_type2", issue = "none")] + #[rustc_const_stable(feature = "const_assert_type2", since = "CURRENT_RUSTC_VERSION")] #[rustc_safe_intrinsic] #[rustc_nounwind] pub fn assert_mem_uninitialized_valid(); diff --git a/library/core/src/mem/mod.rs b/library/core/src/mem/mod.rs index d7abc9a0e23..82ce901140a 100644 --- a/library/core/src/mem/mod.rs +++ b/library/core/src/mem/mod.rs @@ -647,7 +647,8 @@ pub const fn needs_drop() -> bool { #[allow(deprecated)] #[rustc_diagnostic_item = "mem_zeroed"] #[track_caller] -pub unsafe fn zeroed() -> T { +#[rustc_const_stable(feature = "const_mem_zeroed", since = "CURRENT_RUSTC_VERSION")] +pub const unsafe fn zeroed() -> T { // SAFETY: the caller must guarantee that an all-zero value is valid for `T`. unsafe { intrinsics::assert_zero_valid::(); diff --git a/tests/ui/consts/assert-type-intrinsics.rs b/tests/ui/consts/assert-type-intrinsics.rs index b4fd423becd..32b5f5c92c5 100644 --- a/tests/ui/consts/assert-type-intrinsics.rs +++ b/tests/ui/consts/assert-type-intrinsics.rs @@ -1,5 +1,4 @@ #![feature(never_type)] -#![feature(const_assert_type2)] #![feature(core_intrinsics)] use std::intrinsics; diff --git a/tests/ui/consts/assert-type-intrinsics.stderr b/tests/ui/consts/assert-type-intrinsics.stderr index 3c03b03deee..66c4f0f9cd6 100644 --- a/tests/ui/consts/assert-type-intrinsics.stderr +++ b/tests/ui/consts/assert-type-intrinsics.stderr @@ -1,20 +1,20 @@ error[E0080]: evaluation of constant value failed - --> $DIR/assert-type-intrinsics.rs:12:9 + --> $DIR/assert-type-intrinsics.rs:11:9 | LL | MaybeUninit::::uninit().assume_init(); - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'aborted execution: attempted to instantiate uninhabited type `!`', $DIR/assert-type-intrinsics.rs:12:36 + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'aborted execution: attempted to instantiate uninhabited type `!`', $DIR/assert-type-intrinsics.rs:11:36 error[E0080]: evaluation of constant value failed - --> $DIR/assert-type-intrinsics.rs:16:9 + --> $DIR/assert-type-intrinsics.rs:15:9 | LL | intrinsics::assert_mem_uninitialized_valid::<&'static i32>(); - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'aborted execution: attempted to leave type `&i32` uninitialized, which is invalid', $DIR/assert-type-intrinsics.rs:16:9 + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'aborted execution: attempted to leave type `&i32` uninitialized, which is invalid', $DIR/assert-type-intrinsics.rs:15:9 error[E0080]: evaluation of constant value failed - --> $DIR/assert-type-intrinsics.rs:20:9 + --> $DIR/assert-type-intrinsics.rs:19:9 | LL | intrinsics::assert_zero_valid::<&'static i32>(); - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'aborted execution: attempted to zero-initialize type `&i32`, which is invalid', $DIR/assert-type-intrinsics.rs:20:9 + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'aborted execution: attempted to zero-initialize type `&i32`, which is invalid', $DIR/assert-type-intrinsics.rs:19:9 error: aborting due to 3 previous errors