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Tracking Issue for const_ops #143802
Description
Feature gate: #![feature(const_ops)]
This is a tracking issue for const-stability of traits in ops.
Public API
// core::ops
#[const_trait]
pub trait Add<Rhs = Self> { ... }
#[const_trait]
pub trait Sub<Rhs = Self> { ... }
#[const_trait]
pub trait Mul<Rhs = Self> { ... }
#[const_trait]
pub trait Div<Rhs = Self> { ... }
#[const_trait]
pub trait Rem<Rhs = Self> { ... }NegNotBitAndBitOrBitXorShlShrAddAssignSubAssignMulAssignDivAssignRemAssignBitAndAssignBitOrAssignBitXorAssignShlAssignShrAssign
Steps / History
(Remember to update the S-tracking-* label when checking boxes.)
- Implementation:
- Final comment period (FCP)1
- Stabilization PR
Activity
Rollup merge of rust-lang#143803 - RalfJung:const-trait-tracking, r=c…
Rollup merge of rust-lang#143803 - RalfJung:const-trait-tracking, r=c…
Unrolled build for #143803
clarfonthey commentedon Jul 14, 2025
Gonna tackle making the rest of the relevant traits in
core::opsconst. Previously, I was going to split this intoconst_arith_opsandconst_bit_ops, but per recommendation, I've un-split them, meaning that no split is going to happen.EDIT: Will include a full list of changes in attached PR, but it's worth noting the relevant traits that will be added to this tracking issue:
NegNotBitAndBitOrBitXorShlShrAddAssignSubAssignMulAssignDivAssignRemAssignBitAndAssignBitOrAssignBitXorAssignShlAssignShrAssignAdditionally, besides the current implementations for primitives, it will include implementations for
Duration,Ipv[46]Addr, references of primitives,Wrapping, andSaturating, since all of those implementations depend on already-const-stable methods and just needed to be marked const with the appropriate stability attribute.In particular, I suspect that the
Assignvariants were omitted back when these traits were originally constified because mutable references weren't stable in const context yet, but they now are, so, there's no reason to not include them as well since most of them are just simple*self = *self op rhsimpls anyway.fee1-dead commentedon Jul 20, 2025
I don't think a split is necessary here. I think if we were to stablize it we'd likely stabilize them altogether.
Rollup merge of rust-lang#143803 - RalfJung:const-trait-tracking, r=c…
Rollup merge of rust-lang#143949 - clarfonthey:const-arith-ops, r=Ama…
Rollup merge of rust-lang#143949 - clarfonthey:const-arith-ops, r=Ama…
Rollup merge of rust-lang#143949 - clarfonthey:const-arith-ops, r=Ama…
clarfonthey commentedon Aug 11, 2025
#143949 is now merged, so, the issue description needs to be updated. Full list of changes is in the PR description.
Unrolled build for #143949
clarfonthey commentedon Aug 12, 2025
Also highlighting @Zalathar's comment on #143949, which indicated that a perf regression showed up merging these changes: #145236 (comment)
This shouldn't affect perf, but since these operations on primitives were all const despite the traits not being implemented anyway, perhaps they're going through the traits now which is slower? I have absolutely no idea what the actual issue is here, but I figured that I'd share on the tracking issue since the PR is now merged.
Rollup merge of rust-lang#143949 - clarfonthey:const-arith-ops, r=Ama…
rustbot commentedon Aug 29, 2025
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scimind2460 commentedon Sep 13, 2025
Since @clarfonthey has made the PR for the remaining
impls (#143949), can't we check this off?