Who contributed to Rust on August 26, 2026?

10 developers shipped this update, including bors, Jacob Pratt, Jonathan Brouwer, tgross35, folkertdev, MarcoIeni, ChrisDenton, and 许杰友 Jieyou Xu (Joe), and 2 more.

What were the notable Rust updates?

Auto merge of #161772 - JonathanBrouwer:rollup-USO96L6, r=JonathanBrouwer, Rollup merge of #161617 - maxdexh:can-i-has-map-allocator, r=nia-e, and Rollup merge of #160871 - WaffleLapkin:remove_rustc_reservation_impl, r=oli-obk,JonathanBrouwer.

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The Wire · Showcase

Custom allocators land on Box, Rc, Arc

By RepoJournal · Filed 06:59 UTC on August 26, 2026 · About Rust

10 people shipped this

Jonathan Brouwer @JonathanBrouwer 2 cited

bors @bors 1 cited

folkertdev @folkertdev 1 cited

MarcoIeni @marcoieni 1 cited

许杰友 Jieyou Xu (Joe) @jieyouxu 1 cited

Jacob Pratt @jhpratt

tgross35 @tgross35

ChrisDenton @ChrisDenton

Weihang Lo @weihanglo

Ubiratan Soares @ubiratansoares

Rust's core smart pointers just got a long-awaited upgrade, and the compiler is shedding legacy machinery to make room.

A rollup merging 13 PRs [1] brings custom allocators to `(try_)map` on `Box`, `Rc`, and `Arc`, a change that lets you keep your allocator strategy through transformations without resorting to unsound workarounds, though `UniqueArc` and `UniqueRc` are deliberately left out because "too much allocator-related API is missing atm" [2]. The same merge also fixes anon const type recovery in HIR lowering [1], adds an internal DSL for testing binders [1], and corrects debugger visualizer tuple child ordering with PDB debug info [1]. Meanwhile, the deprecated `#[rustc_reservation_impl]` attribute is being removed entirely, closing the door on machinery that only ever had one use case [3]. Over on compiler-builtins, complex number multiplication and division libcalls are now implemented [4], and the CI pipeline is expanding to test on a Canonical-provided `s390x` runner [5]. The team repo formalized a new `wg-build-script` working group [6], signaling deeper investment in build script ergonomics. With 139 commits across 5 repos, the focus is on correctness and infrastructure, not headline features, but allocator support is the one you'll feel in production.

Action items

→ Review your use of Box::map with custom allocators once the next Rust nightly lands rust-lang/rust [plan]
→ Watch for the s390x CI results in compiler-builtins if you target that architecture rust-lang/compiler-builtins [monitor]
→ Track the wg-build-script working group for upcoming build script improvements rust-lang/team [monitor]

References

[1] Auto merge of #161772 - JonathanBrouwer:rollup-USO96L6, r=JonathanBrouwer rust-lang/rust
[2] Rollup merge of #161617 - maxdexh:can-i-has-map-allocator, r=nia-e rust-lang/miri
[3] Rollup merge of #160871 - WaffleLapkin:remove_rustc_reservation_impl, r=oli-obk,JonathanBrouwer rust-lang/rust
[4] implement `Complex` mul and div libcalls ↗ rust-lang/compiler-builtins
[5] ci: build and test with s390x-resolute runner rust-lang/compiler-builtins
[6] Merge pull request #2709 from weihanglo/wg-build-script rust-lang/team

Quick answers

What shipped in Rust on August 26, 2026?: Rust's core smart pointers just got a long-awaited upgrade, and the compiler is shedding legacy machinery to make room. In total, 139 commits and 16 pull requests landed.
Who contributed to Rust on August 26, 2026?: 10 developers shipped this update, including bors, Jacob Pratt, Jonathan Brouwer, tgross35, folkertdev, MarcoIeni, ChrisDenton, and 许杰友 Jieyou Xu (Joe), and 2 more.
What were the notable Rust updates?: Auto merge of #161772 - JonathanBrouwer:rollup-USO96L6, r=JonathanBrouwer, Rollup merge of #161617 - maxdexh:can-i-has-map-allocator, r=nia-e, and Rollup merge of #160871 - WaffleLapkin:remove_rustc_reservation_impl, r=oli-obk,JonathanBrouwer.

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