diff --git a/library/core/src/cmp.rs b/library/core/src/cmp.rs index 03b120fbf0c3..6419ae991135 100644 --- a/library/core/src/cmp.rs +++ b/library/core/src/cmp.rs @@ -381,7 +381,8 @@ pub struct AssertParamIsEq { /// /// assert_eq!(2.cmp(&1), Ordering::Greater); /// ``` -#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)] +#[derive(Clone, Copy, Eq, PartialOrd, Ord, Debug, Hash)] +#[derive_const(PartialEq)] #[stable(feature = "rust1", since = "1.0.0")] // This is a lang item only so that `BinOp::Cmp` in MIR can return it. // It has no special behavior, but does require that the three variants diff --git a/library/core/src/cmp/bytewise.rs b/library/core/src/cmp/bytewise.rs index a06a5227fe28..7d61c9345ecf 100644 --- a/library/core/src/cmp/bytewise.rs +++ b/library/core/src/cmp/bytewise.rs @@ -17,11 +17,15 @@ /// - Neither `Self` nor `Rhs` have provenance, so integer comparisons are correct. /// - `>::{eq,ne}` are equivalent to comparing the bytes. #[rustc_specialization_trait] -pub(crate) unsafe trait BytewiseEq: PartialEq + Sized {} +#[const_trait] +pub(crate) unsafe trait BytewiseEq: + ~const PartialEq + Sized +{ +} macro_rules! is_bytewise_comparable { ($($t:ty),+ $(,)?) => {$( - unsafe impl BytewiseEq for $t {} + unsafe impl const BytewiseEq for $t {} )+}; } diff --git a/library/core/src/intrinsics/mod.rs b/library/core/src/intrinsics/mod.rs index 1ece3d9bd5e4..b11972600fa4 100644 --- a/library/core/src/intrinsics/mod.rs +++ b/library/core/src/intrinsics/mod.rs @@ -2208,6 +2208,7 @@ pub const fn ptr_guaranteed_cmp(ptr: *const T, other: *const T) -> u8 { /// [valid]: crate::ptr#safety #[rustc_nounwind] #[rustc_intrinsic] +#[rustc_const_unstable(feature = "const_cmp", issue = "143800")] pub const unsafe fn compare_bytes(left: *const u8, right: *const u8, bytes: usize) -> i32; /// See documentation of [`std::hint::black_box`] for details. diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs index 2f701171505c..fedc4dada203 100644 --- a/library/core/src/lib.rs +++ b/library/core/src/lib.rs @@ -103,6 +103,7 @@ #![feature(cfg_select)] #![feature(cfg_target_has_reliable_f16_f128)] #![feature(const_carrying_mul_add)] +#![feature(const_cmp)] #![feature(const_destruct)] #![feature(const_eval_select)] #![feature(core_intrinsics)] @@ -146,6 +147,7 @@ #![feature(const_trait_impl)] #![feature(decl_macro)] #![feature(deprecated_suggestion)] +#![feature(derive_const)] #![feature(doc_cfg)] #![feature(doc_cfg_hide)] #![feature(doc_notable_trait)] diff --git a/library/core/src/slice/cmp.rs b/library/core/src/slice/cmp.rs index 5ce72b46eee3..1eda8bc1bec4 100644 --- a/library/core/src/slice/cmp.rs +++ b/library/core/src/slice/cmp.rs @@ -8,9 +8,10 @@ use crate::ops::ControlFlow; #[stable(feature = "rust1", since = "1.0.0")] -impl PartialEq<[U]> for [T] +#[rustc_const_unstable(feature = "const_cmp", issue = "143800")] +impl const PartialEq<[U]> for [T] where - T: PartialEq, + T: ~const PartialEq, { fn eq(&self, other: &[U]) -> bool { SlicePartialEq::equal(self, other) @@ -94,6 +95,8 @@ fn __chaining_ge(&self, other: &Self) -> ControlFlow { #[doc(hidden)] // intermediate trait for specialization of slice's PartialEq +#[const_trait] +#[rustc_const_unstable(feature = "const_cmp", issue = "143800")] trait SlicePartialEq { fn equal(&self, other: &[B]) -> bool; @@ -103,9 +106,10 @@ fn not_equal(&self, other: &[B]) -> bool { } // Generic slice equality -impl SlicePartialEq for [A] +#[rustc_const_unstable(feature = "const_cmp", issue = "143800")] +impl const SlicePartialEq for [A] where - A: PartialEq, + A: ~const PartialEq, { default fn equal(&self, other: &[B]) -> bool { if self.len() != other.len() { @@ -115,11 +119,14 @@ impl SlicePartialEq for [A] // Implemented as explicit indexing rather // than zipped iterators for performance reasons. // See PR https://github.com/rust-lang/rust/pull/116846 - for idx in 0..self.len() { + // FIXME(const_hack): make this a `for idx in 0..self.len()` loop. + let mut idx = 0; + while idx < self.len() { // bound checks are optimized away if self[idx] != other[idx] { return false; } + idx += 1; } true @@ -128,9 +135,10 @@ impl SlicePartialEq for [A] // When each element can be compared byte-wise, we can compare all the bytes // from the whole size in one call to the intrinsics. -impl SlicePartialEq for [A] +#[rustc_const_unstable(feature = "const_cmp", issue = "143800")] +impl const SlicePartialEq for [A] where - A: BytewiseEq, + A: ~const BytewiseEq, { fn equal(&self, other: &[B]) -> bool { if self.len() != other.len() { diff --git a/library/core/src/str/traits.rs b/library/core/src/str/traits.rs index 42ffc591b5bb..d0f2b9226bf6 100644 --- a/library/core/src/str/traits.rs +++ b/library/core/src/str/traits.rs @@ -23,7 +23,8 @@ fn cmp(&self, other: &str) -> Ordering { } #[stable(feature = "rust1", since = "1.0.0")] -impl PartialEq for str { +#[rustc_const_unstable(feature = "const_cmp", issue = "143800")] +impl const PartialEq for str { #[inline] fn eq(&self, other: &str) -> bool { self.as_bytes() == other.as_bytes() diff --git a/tests/ui/consts/const-compare-bytes-ub.rs b/tests/ui/consts/const-compare-bytes-ub.rs index 0bc8585a4eed..7e3df92a2bf5 100644 --- a/tests/ui/consts/const-compare-bytes-ub.rs +++ b/tests/ui/consts/const-compare-bytes-ub.rs @@ -1,6 +1,6 @@ //@ check-fail -#![feature(core_intrinsics)] +#![feature(core_intrinsics, const_cmp)] use std::intrinsics::compare_bytes; use std::mem::MaybeUninit; diff --git a/tests/ui/consts/const-compare-bytes.rs b/tests/ui/consts/const-compare-bytes.rs index cd5cdfd0400e..9563375555cf 100644 --- a/tests/ui/consts/const-compare-bytes.rs +++ b/tests/ui/consts/const-compare-bytes.rs @@ -1,6 +1,6 @@ //@ run-pass -#![feature(core_intrinsics)] +#![feature(core_intrinsics, const_cmp)] use std::intrinsics::compare_bytes; fn main() { diff --git a/tests/ui/traits/const-traits/const-impl-trait.rs b/tests/ui/traits/const-traits/const-impl-trait.rs index dc960422a4a4..da28d9a47c31 100644 --- a/tests/ui/traits/const-traits/const-impl-trait.rs +++ b/tests/ui/traits/const-traits/const-impl-trait.rs @@ -1,7 +1,7 @@ //@ compile-flags: -Znext-solver //@ known-bug: #110395 -// Broken until we have `const PartialEq` impl in stdlib +// Broken until `(): const PartialEq` #![allow(incomplete_features)] #![feature(const_trait_impl, const_cmp, const_destruct)] diff --git a/tests/ui/traits/const-traits/match-non-const-eq.gated.stderr b/tests/ui/traits/const-traits/match-non-const-eq.gated.stderr deleted file mode 100644 index 89e59e5db6ed..000000000000 --- a/tests/ui/traits/const-traits/match-non-const-eq.gated.stderr +++ /dev/null @@ -1,12 +0,0 @@ -error[E0015]: cannot match on `str` in constant functions - --> $DIR/match-non-const-eq.rs:7:9 - | -LL | "a" => (), //FIXME [gated]~ ERROR can't compare `str` with `str` in const contexts - | ^^^ - | - = note: `str` cannot be compared in compile-time, and therefore cannot be used in `match`es - = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants - -error: aborting due to 1 previous error - -For more information about this error, try `rustc --explain E0015`. diff --git a/tests/ui/traits/const-traits/match-non-const-eq.rs b/tests/ui/traits/const-traits/match-non-const-eq.rs index 73f8af86bd05..03adb8dc5a4e 100644 --- a/tests/ui/traits/const-traits/match-non-const-eq.rs +++ b/tests/ui/traits/const-traits/match-non-const-eq.rs @@ -1,11 +1,12 @@ -//@ known-bug: #110395 //@ revisions: stock gated -#![cfg_attr(gated, feature(const_trait_impl))] +#![cfg_attr(gated, feature(const_trait_impl, const_cmp))] +//@[gated] check-pass const fn foo(input: &'static str) { match input { - "a" => (), //FIXME [gated]~ ERROR can't compare `str` with `str` in const contexts - //FIXME ~^ ERROR cannot match on `str` in constant functions + "a" => (), + //[stock]~^ ERROR cannot match on `str` in constant functions + //[stock]~| ERROR `PartialEq` is not yet stable as a const trait _ => (), } } diff --git a/tests/ui/traits/const-traits/match-non-const-eq.stock.stderr b/tests/ui/traits/const-traits/match-non-const-eq.stock.stderr index 89e59e5db6ed..5b662447bde1 100644 --- a/tests/ui/traits/const-traits/match-non-const-eq.stock.stderr +++ b/tests/ui/traits/const-traits/match-non-const-eq.stock.stderr @@ -1,12 +1,26 @@ -error[E0015]: cannot match on `str` in constant functions +error[E0658]: cannot match on `str` in constant functions --> $DIR/match-non-const-eq.rs:7:9 | -LL | "a" => (), //FIXME [gated]~ ERROR can't compare `str` with `str` in const contexts +LL | "a" => (), | ^^^ | = note: `str` cannot be compared in compile-time, and therefore cannot be used in `match`es = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants + = note: see issue #143874 for more information + = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable + = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date -error: aborting due to 1 previous error +error: `PartialEq` is not yet stable as a const trait + --> $DIR/match-non-const-eq.rs:7:9 + | +LL | "a" => (), + | ^^^ + | +help: add `#![feature(const_cmp)]` to the crate attributes to enable + | +LL + #![feature(const_cmp)] + | -For more information about this error, try `rustc --explain E0015`. +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0658`.