Rollup of 4 pull requests

[matthiaskrgr]

Successful merges:

• Visit type in process_projection_elem. #91294 (Visit type in process_projection_elem.)
• Bump compiler_builtins to 0.1.55 to bring in fixes for targets lackin… #91340 (Bump compiler_builtins to 0.1.55 to bring in fixes for targets lackin…)
• Only show notable traits if both types are the same #91366 (Only show notable traits if both types are the same)
• Emit a warning on generic parameters with doc comments #91397 (Emit a warning on generic parameters with doc comments)

Failed merges:

r? @ghost
@rustbot modify labels: rollup

Create a similar rollup

[matthiaskrgr]

@bors r+ rollup=never p=4

[bors]

📌 Commit 7baafb1 has been approved by matthiaskrgr

[bors]

⌛ Testing commit 7baafb1 with merge d384ff7...

[bors]

☀️ Test successful - checks-actions
Approved by: matthiaskrgr
Pushing d384ff7 to master...

[rust-timer]

Finished benchmarking commit (d384ff7): comparison url.

Summary: This change led to very large relevant mixed results 🤷 in compiler performance.

• Large improvement in instruction counts (up to -2.7% on incr-unchanged builds of deeply-nested-async)
• Very large regression in instruction counts (up to 7.1% on incr-unchanged builds of clap-rs)

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

Next Steps: If you can justify the regressions found in this perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please open an issue or create a new PR that fixes the regressions, add a comment linking to the newly created issue or PR, and then add the perf-regression-triaged label to this PR.

@rustbot label: +perf-regression

[rylev]

@matthiaskrgr this seems a bit hard to tell where the regression is coming from, but it is a quite a large regression in a real-world crate (albeit one that is a tiny bit noisy). #91366 and #91397 only really touch rustdoc so that's unlikely the culprit. PRs where code is removed or added can be a source of regressions so I wouldn't rule out the others, but we may want to investigate the bump of compiler builtins first.