The Wire · Showcase
RUST DELEGATION LANDS, ANALYZER FIXES REFERENCE COERCION BUG
By RepoJournal · Filed · About Rust
The compiler shipped delegation without method call generation [ref:6], while rust-analyzer fixed a critical assist that was stacking references instead of converting them [ref:13].
Delegation is now live in the compiler [1], removing the old method call generation path and reusing the method probing engine to handle adjustments. This extends support to trait methods and sets the foundation for free function delegation. The change is part of the larger delegation work tracked in rust-lang/rust#118212 and ships in today's rollup [3], which also includes stdarch updates and better error messages for unimplemented trait methods [3]. Over on rust-analyzer, a nasty bug in the add_reference_here assist is fixed [2]: it was incorrectly stacking references when converting &T to &mut T instead of modifying the existing reference. The fix ships in the latest nightly [12]. On the infrastructure side, the tidy tool got a cleanup [4], and the LLDB debugging integration finally has proper callback registration [5]. Crates.io saw routine updates to the tsoracle driver ecosystem [6] [7] [8], plus a crate deletion [9]. Annotate-snippets pulled in two consecutive prek dependency updates [10] [11], with v0.4.3 fixing stat-only hook rewrites.
Action items
- → Update to latest rust-analyzer nightly if you use add_reference_here assist rust-lang/rust-analyzer [immediate]
- → Test delegation in your codebase after this rollup lands rust-lang/rust [plan]
- → Monitor delegation stability across next few nightly cycles rust-lang/rust [monitor]
References
- [1] Rollup merge of #156541 - aerooneqq:delegation-no-method-call, r=petrochenkov rust-lang/rust
- [2] fix(assists/add_reference_here): _modify_ the reference type when dealing with &T->&mut T ↗ rust-lang/rust-analyzer
- [3] Auto merge of #156967 - JonathanBrouwer:rollup-cDWgT7T, r=JonathanBrouwer rust-lang/rust
- [4] Rollup merge of #156761 - kcx1:fix/156730, r=tgross35 rust-lang/rust
- [5] Rollup merge of #156899 - Walnut356:lldb_batchmode, r=jieyouxu rust-lang/rust
- [6] Update crate `tsoracle-driver-file` rust-lang/crates.io-index
- [7] Update crate `tsoracle-client` rust-lang/crates.io-index
- [8] Update crate `tsoracle-server` rust-lang/crates.io-index
- [9] Delete crate `ax-plat-dyn` rust-lang/crates.io-index
- [10] chore(deps): Update Prek to v0.4.3 ↗ rust-lang/annotate-snippets-rs
- [11] chore(deps): Update Prek to v0.4.2 ↗ rust-lang/annotate-snippets-rs
- [12] nightly ↗ rust-lang/rust-analyzer
FAQ
- What changed in Rust on May 27, 2026?
- The compiler shipped delegation without method call generation , while rust-analyzer fixed a critical assist that was stacking references instead of converting them .
- What should Rust teams do about it?
- Update to latest rust-analyzer nightly if you use add_reference_here assist • Test delegation in your codebase after this rollup lands • Monitor delegation stability across next few nightly cycles
- Which Rust repositories shipped on May 27, 2026?
- rust-lang/rust, rust-lang/rust-analyzer, rust-lang/crates.io-index, rust-lang/annotate-snippets-rs