Resolver: Batched Import Resolution #145108

LorrensP-2158466 · 2025-08-08T15:54:37Z

Transforms the current algorithm for resolving imports to a batched algorithm. Every import in the indeterminate_imports set is resolved in isolation. This is the only real difference from the current algorithm.

r? petrochenkov

compiler/rustc_resolve/src/lib.rs

compiler/rustc_resolve/src/imports.rs

LorrensP-2158466 · 2025-08-11T19:29:42Z

Code looks a little better now and should be more correct than the previous commits, but I have yet to find a way to resolve the current test failures.

LorrensP-2158466 · 2025-08-11T20:34:04Z

Okey, I did fix core not being built, but those other errors happened again. We now resolve the prelude import path when we create such an import at build_reduced_graph phase.

petrochenkov · 2025-08-11T22:39:59Z

Could you update the tests to make CI green, so I can see the difference?
(Even if the changes do not seem correct.)

tests/ui/imports/ambiguous-9.rs

tests/ui/imports/glob-conflict-cross-crate-1.rs

tests/ui/proc-macro/derive-helper-legacy-spurious.rs

petrochenkov · 2025-08-12T17:43:51Z

Moving prelude_import processing to build_reduced_graph may also be necessary for #139493.

LorrensP-2158466 · 2025-08-12T17:49:54Z

I'll create a pr for it.

compiler/rustc_resolve/src/imports.rs

petrochenkov · 2025-12-03T15:26:36Z

We should be able to land this after merging #147984 and #149596 (and maybe also #149058).

LorrensP-2158466 · 2025-12-03T17:13:01Z

Did you also want this to include the parallelisation of the algorithm in this pr? If so, I can start looking into it while waiting on those pr's.

petrochenkov · 2025-12-03T17:14:54Z

Did you also want this to include the parallelisation of the algorithm in this pr?

No, of course not, it is nontrivial and will also take at least weeks, if not more.
(But it would certainly be good to look into it in advance.)

LorrensP-2158466 · 2025-12-03T17:18:15Z

No, of course not, it is nontrivial and will also take at least weeks, if not more.
(But it would certainly be good to look into it in advance.)

Yeah, that's what I thought 😅. Will look into it!

resolve: Preserve ambiguous glob reexports in crate metadata So in cross-crate scenarios they can work in the same way as in crate-local scenarios. Change Description: #147984 (comment) Resurrection of #114682. One of unblocking steps for #145108. Fixes #36837.

…r=petrochenkov Resolve the prelude import in `build_reduced_graph` This pr tries to resolve the prelude import at the `build_reduced_graph` stage. Part of batched import resolution in rust-lang/rust#145108 (cherry picked commit) and maybe needed for rust-lang/rust#139493. r? petrochenkov

…etrochenkov Test: Ambigious bindings in same namespace with the same res Add a test based on the discussion [here](https://rust-lang.zulipchat.com/#narrow/channel/421156-gsoc/topic/Project.3A.20Parallel.20Macro.20Expansion/near/542316157) and related to rust-lang/rust#145575 (comment). This is the most reduced form I could create that passes on nightly but fails with rust-lang/rust#145108 (see [#gsoc > Project: Parallel Macro Expansion @ 💬](https://rust-lang.zulipchat.com/#narrow/channel/421156-gsoc/topic/Project.3A.20Parallel.20Macro.20Expansion/near/542335131)). Also not sure about the test names. r? `@petrochenkov`

…chenkov use module_child index as disambiguator for external items When defining the items of an external module, if that item is an underscore we use it's index as the disambiguator. This is needed for parallel import resolution, which is being worked on in rust-lang/rust#145108. r? `@petrochenkov`

LorrensP-2158466 · 2026-01-13T18:48:13Z

I finally rebased... should have done that way sooner, but it went well. The only problem is that imports/ambiguous-9.rs is panicking:

thread 'rustc' (16848976) panicked at compiler/rustc_resolve/src/imports.rs:328:9:
assertion failed: !d1.warn_ambiguity.get()
stack backtrace:

Luckily I'm following issues/pr's made to the resolver, so I remembered it was related to #150927 and fixed in #150939. I removed it for now, couldn't find another clean way to ignore it. When that pr is merged I can just remove the commit.

Also the RustEmbed hack can be removed, right? Because of the conflicting importsvisibilities of the imported derive macro.

petrochenkov · 2026-01-13T19:05:21Z

Also the RustEmbed hack can be removed, right? Because of the conflicting importsvisibilities of the imported derive macro.

IIRC, the hack changed the resolution priorities to avoid breakage, while #149596 only adds a warning for the conflicting visibilities, so the hack will still be needed in some form.

petrochenkov · 2026-01-13T19:07:14Z

Although if a new patch version of rust-embed is published, and the issue doesn't occur in other known crates, then maybe it won't be needed. We'll run crater on this PR in any case, once all the blocking PRs are merged.

LorrensP-2158466 · 2026-01-14T13:43:25Z

Although if a new patch version of rust-embed is published

The patch was published a while back as rust-embed/8.8.0. The latest version is 8.10.0. Though this error happens in dependencies, everything works fine crate-local.

and the issue doesn't occur in other known crates, then maybe it won't be needed

IIRC, rust-embed was the only crate which had this pattern and caused problems for downstream crates.

rust-bors · 2026-01-14T16:49:34Z

☔ The latest upstream changes (presumably #151107) made this pull request unmergeable. Please resolve the merge conflicts.

Collect side effects from the current set of undetermined imports and only apply them at the end. + Bless tests

rustbot · 2026-01-14T17:39:49Z

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.

LorrensP-2158466 · 2026-01-14T17:41:45Z

Had to rebase again, in the last commit the test tests/ui/imports/ambiguous-panic-globvsglob.rs is changed because of the mismatched stderr output. I don't really see if it's still correct.

rust-log-analyzer · 2026-01-14T18:28:08Z

The job x86_64-gnu-tools failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)


failures:

---- names/name-resolution.md - Name_resolution::Expansion_time_name_resolution::Imports::Ambiguities (line 269) stdout ----
##[error]error: internal compiler error: compiler/rustc_middle/src/middle/privacy.rs:187:21: DefId(0:10 ~ rust_out[9c1d]::m3::{use#1}): reachable Restricted(DefId(0:0 ~ rust_out[9c1d])) > nominal Restricted(DefId(0:8 ~ rust_out[9c1d]::m3))
   --> names/name-resolution.md:285:9
    |
285 |     use super::m2::*;
    |         ^^^^^^^^^


thread 'rustc' (37218) panicked at compiler/rustc_middle/src/middle/privacy.rs:187:21:
Box<dyn Any>
stack backtrace:
   0: std::panicking::begin_panic::<rustc_errors::ExplicitBug>
   1: <rustc_errors::diagnostic::BugAbort as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
   2: <rustc_errors::DiagCtxtHandle>::span_bug::<rustc_span::span_encoding::Span, alloc::string::String>
   3: rustc_middle::util::bug::opt_span_bug_fmt::<rustc_span::span_encoding::Span>::{closure#0}
   4: rustc_middle::ty::context::tls::with_opt::<rustc_middle::util::bug::opt_span_bug_fmt<rustc_span::span_encoding::Span>::{closure#0}, !>::{closure#0}
   5: rustc_middle::ty::context::tls::with_context_opt::<rustc_middle::ty::context::tls::with_opt<rustc_middle::util::bug::opt_span_bug_fmt<rustc_span::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
   6: rustc_middle::util::bug::span_bug_fmt::<rustc_span::span_encoding::Span>
   7: <rustc_middle::middle::privacy::EffectiveVisibilities>::check_invariants
   8: rustc_privacy::effective_visibilities
      [... omitted 2 frames ...]
   9: std::panicking::catch_unwind::<(), core::panic::unwind_safe::AssertUnwindSafe<rustc_interface::passes::analysis::{closure#0}::{closure#1}::{closure#0}>>
  10: <rustc_session::session::Session>::time::<(), rustc_interface::passes::analysis::{closure#0}>
  11: rustc_interface::passes::analysis
      [... omitted 2 frames ...]
  12: <std::thread::local::LocalKey<core::cell::Cell<*const ()>>>::with::<rustc_middle::ty::context::tls::enter_context<<rustc_middle::ty::context::GlobalCtxt>::enter<rustc_interface::passes::create_and_enter_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}, core::option::Option<rustc_interface::queries::Linker>>::{closure#1}, core::option::Option<rustc_interface::queries::Linker>>::{closure#0}, core::option::Option<rustc_interface::queries::Linker>>
  13: <rustc_middle::ty::context::TyCtxt>::create_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_interface::passes::create_and_enter_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}>
  14: <rustc_interface::passes::create_and_enter_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>::{closure#2} as core::ops::function::FnOnce<(&rustc_session::session::Session, rustc_middle::ty::context::CurrentGcx, alloc::sync::Arc<rustc_data_structures::jobserver::Proxy>, &std::sync::once_lock::OnceLock<rustc_middle::ty::context::GlobalCtxt>, &rustc_data_structures::sync::worker_local::WorkerLocal<rustc_middle::arena::Arena>, &rustc_data_structures::sync::worker_local::WorkerLocal<rustc_hir::Arena>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2})>>::call_once::{shim:vtable#0}
  15: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>
  16: std::panicking::catch_unwind::<(), core::panic::unwind_safe::AssertUnwindSafe<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}::{closure#0}>>
  17: <scoped_tls::ScopedKey<rustc_span::SessionGlobals>>::set::<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}::{closure#0}, ()>
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

---

note: compiler flags: --crate-type bin

query stack during panic:
#0 [effective_visibilities] checking effective visibilities
#1 [analysis] running analysis passes on crate `rust_out`
end of query stack
error: aborting due to 1 previous error

Couldn't compile the test.

rust-bors · 2026-01-15T16:33:26Z

☔ The latest upstream changes (presumably #151158) made this pull request unmergeable. Please resolve the merge conflicts.

rustbot assigned petrochenkov Aug 8, 2025

rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Aug 8, 2025

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apiraino mentioned this pull request Jan 5, 2026

Diesel stops building with nightly-2025-12-10 #149845

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LorrensP-2158466 added 4 commits January 14, 2026 18:39

Resolver: Batched import resolution.

93443a1

Collect side effects from the current set of undetermined imports and only apply them at the end. + Bless tests

hack for RustEmbed with updated test

de379ca

remove ambiguous-9 for now because of panic, another pr fixes this

a77cc1b

Bless and change test for review.

0f6b71c

LorrensP-2158466 force-pushed the batched-import-resolution branch from 4632f09 to 0f6b71c Compare January 14, 2026 17:39

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