Use special DefIds for aliases by ChayimFriedman2 · Pull Request #155981 · rust-lang/rust

ChayimFriedman2 · 2026-04-30T03:16:50Z

Renewal of #155025, after AliasTermKind was also ported.

Like we do for other things for better experience in rust-analyzer.

It's possible now that the AliasTyKind and AliasTermKind contains the DefId.

It does require a few try_into().unwrap()s since in the solver's consider_X_candidate() only get an untyped DefId. It's possible to reduce that considerably if we'd pass them the typed def id as a parameter, but I don't know what will be the impact on perf. Should I try to pursue that?

r? lcnr

Like we do for other things for better experience in rust-analyzer. It's possible now that the `AliasTyKind` and `AliasTermKind` contains the DefId. It does require a few `try_into().unwrap()`s since in the solver's `consider_X_candidate()` only get an untyped `DefId`. It's possible to reduce that considerably if we'd pass them the typed def id as a parameter, but I don't know what will be the impact on perf.

rustbot · 2026-05-04T03:27:29Z

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

ChayimFriedman2 · 2026-05-04T03:30:28Z

@bors try @rust-timer queue

rust-timer · 2026-05-04T03:30:31Z

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

rust-bors · 2026-05-04T03:30:33Z

⌛ Trying commit 5e8cb76 with merge ce54c3a…

To cancel the try build, run the command @bors try cancel.

Workflow: https://github.com/rust-lang/rust/actions/runs/25299606130

Use special DefIds for aliases

ChayimFriedman2 · 2026-05-04T04:51:26Z

@bors cancel

rust-bors · 2026-05-04T04:51:29Z

❗ There is currently no auto build in progress on this PR.

Hint: There is a pending try build on this PR. Maybe you meant to cancel it? You can do that using @bors try cancel.

rustbot assigned lcnr Apr 30, 2026

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. WG-trait-system-refactor The Rustc Trait System Refactor Initiative (-Znext-solver) labels Apr 30, 2026