If a trait item appears in rustdoc search, hide the corrosponding impl items

[lolbinarycat]

fixes #138251

cc @notriddle

[lolbinarycat]

sometimes traitParent is not set properly for cross-crate implementations (eg. alloc::str::Bytes::last is not getting linked to Iterator::last).

this has been fixed (and removed from the PR description), i just needed to also be checking Cache::external_paths when resolving trait_parent_idx.

[lolbinarycat]

Right, I just remembered why my original design had its own deduplication pass, instead of leveraging the existing deduplication pass:

if the user searches for char::from, we should show them both ascii::Char::from and char::from. its only when a search matches the actual trait item (in this case, From::from) where we should perform this deduplication.

[lolbinarycat]

I believe I managed to get it working using notriddle's idea for how the search index data should be structured, but with my original idea of having two deduplication passes.

[lolbinarycat]

ok so apparently some impls for unnamable traits get lowered and then filtered out later? which seems mildly wasteful but ig in the meantime i need to remove this debug assertion.

[rustbot]

r? @notriddle

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[rustbot]

Some changes occurred in GUI tests.

cc @GuillaumeGomez

Some changes occurred in HTML/CSS/JS.

cc @GuillaumeGomez, @jsha, @lolbinarycat

[bors]

☔ The latest upstream changes (presumably #146700) made this pull request unmergeable. Please resolve the merge conflicts.

[lolbinarycat]

well that's a new error...

[notriddle]

I've pushed a commit onto your branch that I'm pretty sure will fix that.

After running these two commands...

2025-10-01T19:14:09.9965297Z + python3 ../x.py doc bootstrap
2025-10-01T19:14:32.7233881Z + RUSTDOCFLAGS=--document-private-items --document-hidden-items python3 ../x.py doc compiler --stage 1

... the CI run crashed in stage0, which contains beta's bootstrap toolchain, not the build of cargo and rustdoc that's actually in the PR.

Command `/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo doc --target x86_64-unknown-linux-gnu -Zbinary-dep-depinfo -j 4 -Zroot-dir=/checkout --locked --color always --release --features llvm --manifest-path /checkout/compiler/rustc/Cargo.toml -Zskip-rustdoc-fingerprint --no-deps -Zrustdoc-map -p rustc-main -p rustc_abi -p rustc_arena -p rustc_ast -p rustc_ast_ir -p rustc_ast_lowering -p rustc_ast_passes -p rustc_ast_pretty -p rustc_attr_parsing -p rustc_baked_icu_data -p rustc_borrowck -p rustc_builtin_macros -p rustc_codegen_llvm -p rustc_codegen_ssa -p rustc_const_eval -p rustc_data_structures -p rustc_driver -p rustc_driver_impl -p rustc_error_codes -p rustc_error_messages -p rustc_errors -p rustc_expand -p rustc_feature -p rustc_fluent_macro -p rustc_fs_util -p rustc_graphviz -p rustc_hashes -p rustc_hir -p rustc_hir_analysis -p rustc_hir_id -p rustc_hir_pretty -p rustc_hir_typeck -p rustc_incremental -p rustc_index -p rustc_index_macros -p rustc_infer -p rustc_interface -p rustc_lexer -p rustc_lint -p rustc_lint_defs -p rustc_llvm -p rustc_log -p rustc_macros -p rustc_metadata -p rustc_middle -p rustc_mir_build -p rustc_mir_dataflow -p rustc_mir_transform -p rustc_monomorphize -p rustc_next_trait_solver -p rustc_parse -p rustc_parse_format -p rustc_passes -p rustc_pattern_analysis -p rustc_privacy -p rustc_proc_macro -p rustc_public -p rustc_public_bridge -p rustc_query_impl -p rustc_query_system -p rustc_resolve -p rustc_sanitizers -p rustc_serialize -p rustc_session -p rustc_span -p rustc_symbol_mangling -p rustc_target -p rustc_thread_pool -p rustc_trait_selection -p rustc_traits -p rustc_transmute -p rustc_ty_utils -p rustc_type_ir -p rustc_type_ir_macros -p rustc_windows_rc [workdir=/checkout]` failed with exit code 101

This implies that the problem is just another variant of #147142 where a single docs directory is built from two different versions of rustdoc.

[notriddle]

Squash, then merge?

View changes since this review

[lolbinarycat]

alright, I think this is probably a logical set of commits (maybe the first two could be squashed together).

i wanted to keep removeIdxListAsc in a separate commit in case we want to revert it in the future

[notriddle]

@bors r=GuillaumeGomez,notriddle

[bors]

📌 Commit c7d6857 has been approved by GuillaumeGomez,notriddle

It is now in the queue for this repository.

[bors]

⌛ Testing commit c7d6857 with merge dd09100...

[bors]

☀️ Test successful - checks-actions
Approved by: GuillaumeGomez,notriddle
Pushing dd09100 to master...

[github-actions]

What is this?

This is an experimental post-merge analysis report that shows differences in test outcomes between the merged PR and its parent PR.

Comparing 3b8665c (parent) -> dd09100 (this PR)

Test differences

Show 2 test diffs

2 doctest diffs were found. These are ignored, as they are noisy.

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard dd091003ace19d9556c647d87f7a9cd1e8dcc17e --output-dir test-dashboard

And then open test-dashboard/index.html in your browser to see an overview of all executed tests.

Job duration changes

1. dist-android: 1624.9s -> 1110.3s (-31.7%)
2. dist-apple-various: 4195.7s -> 3334.0s (-20.5%)
3. pr-check-2: 2455.5s -> 2151.1s (-12.4%)
4. x86_64-gnu-llvm-20-1: 3631.2s -> 3194.7s (-12.0%)
5. i686-gnu-nopt-1: 8047.5s -> 7135.5s (-11.3%)
6. dist-aarch64-apple: 7123.4s -> 6316.4s (-11.3%)
7. aarch64-gnu-llvm-20-2: 2443.2s -> 2167.1s (-11.3%)
8. dist-x86_64-windows-gnullvm: 4838.2s -> 5382.5s (11.3%)
9. x86_64-gnu: 7750.3s -> 6972.8s (-10.0%)
10. dist-x86_64-apple: 7448.6s -> 6740.6s (-9.5%)

How to interpret the job duration changes?

Job durations can vary a lot, based on the actual runner instance
that executed the job, system noise, invalidated caches, etc. The table above is provided
mostly for t-infra members, for simpler debugging of potential CI slow-downs.

[rust-timer]

Finished benchmarking commit (dd09100): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

This benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

Results (secondary -1.5%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.5%	[-1.5%, -1.5%]	1
All ❌✅ (primary)	-	-	0

Cycles

This benchmark run did not return any relevant results for this metric.

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 472.69s -> 470.825s (-0.39%)
Artifact size: 387.73 MiB -> 387.79 MiB (0.02%)