Replace `truncate(0)` with `clear()` by xtqqczze · Pull Request #154029 · rust-lang/rust

xtqqczze · 2026-03-18T03:21:08Z

No description provided.

rustbot · 2026-03-18T03:21:11Z

rust-analyzer is developed in its own repository. If possible, consider making this change to rust-lang/rust-analyzer instead.

cc @rust-lang/rust-analyzer

Some changes occurred in src/tools/compiletest

cc @jieyouxu

rustbot · 2026-03-18T03:21:13Z

r? @joboet

rustbot has assigned @joboet.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

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Why was this reviewer chosen?

The reviewer was selected based on:

Owners of files modified in this PR: @ChrisDenton, libs
@ChrisDenton, libs expanded to 8 candidates
Random selection from Mark-Simulacrum, joboet

bjorn3 · 2026-03-18T10:28:01Z

src/tools/rust-analyzer/crates/hir-ty/src/infer/closure/analysis.rs

Please don't modify subtrees like rust-analyzer inside the rust-lang/rust repo unless necessary. Development of rust-analyzer happens at https://github.com/rust-lang/rust-analyzer/

rebased

For future reference do all subtrees have a josh-sync.toml?

Most do. The exceptions I believe are compiler/rustc_codegen_cranelift, compiler/rustc_codegen_gcc and src/tools/rustfmt. Those I think are the only ones that still use git-subtree rather than josh for syncing.

Right, unfortunately there is no reliable method get a list of current subtrees from Git. Perhaps these could be tracked explicitly somewhere?

No need to, just see if triagebot complains. You can skim https://github.com/rust-lang/rust/blob/main/triagebot.toml if you're wondering.

I don't think this is necessary, so please remove this change.

OK I've rebased to remove changes under src/tools/rust-analyzer

I've added the change to src/tools/compiletest back since that doesn't appear to be a subtree.

Kivooeo

approve on compiler/ part, yet requires an approve on library/ part

View changes since this review

cjgillot · 2026-03-19T00:40:46Z

@bors try @rust-timer queue

Replace `truncate(0)` with `clear()`

rust-bors · 2026-03-19T02:50:37Z

☀️ Try build successful (CI)
Build commit: 637b2a9 (637b2a9e6396c8eee79c1faf2b551af705aec553, parent: fd0c901b00ee1e08a250039cdb90258603497e20)

rust-timer · 2026-03-19T03:32:10Z

Finished benchmarking commit (637b2a9): comparison URL.

Overall result: ✅ improvements - no action needed

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

@bors rollup=never
@rustbot label: -S-waiting-on-perf -perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.2%	[-0.3%, -0.1%]	4
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary 0.2%)

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

	mean	range	count
Regressions ❌ (primary)	2.3%	[2.3%, 2.3%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-1.8%	[-1.8%, -1.8%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.2%	[-1.8%, 2.3%]	2

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: 481.003s -> 480.752s (-0.05%)
Artifact size: 396.91 MiB -> 395.01 MiB (-0.48%)

joboet · 2026-03-19T13:31:32Z

src/tools/rust-analyzer/crates/hir-ty/src/infer/closure/analysis.rs

I don't think this is necessary, so please remove this change.

rustbot · 2026-03-19T13:31:52Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

xtqqczze · 2026-03-19T16:18:40Z

@rustbot ready

joboet · 2026-03-28T10:28:32Z

Thanks!
@bors r+ rollup

rust-bors · 2026-03-28T10:28:35Z

📌 Commit b9cd592 has been approved by joboet

It is now in the queue for this repository.

Rollup of 11 pull requests Successful merges: - #152880 (Tweak incorrect assoc item note) - #153526 (Fix LegacyKeyValueFormat report from docker build: i686) - #153613 (interpreter error reporting: remove arguments that are always the same) - #154029 (Replace `truncate(0)` with `clear()`) - #154125 (Inline and remove `DepGraphData::try_mark_parent_green`.) - #154185 (Prevent no_threads RwLock's write() impl from setting mode to -1 when it is locked for reading) - #154394 (Normalize rustc path prefix when testing `-Z track-diagnostics`) - #154450 (Use the normal arg-parsing machinery for `-Zassert-incr-state`) - #154475 (Emit a pre-expansion feature gate warning for `box`'ed struct field patterns) - #154500 (EnumSizeOpt: use Allocation::write_scalar instead of manual endianess logic) - #154502 (interpret: ensure that untupled arguments are actually tuples)

Rollup merge of #154029 - xtqqczze:clear, r=joboet Replace `truncate(0)` with `clear()`

rustbot assigned joboet Mar 18, 2026

bjorn3 reviewed Mar 18, 2026

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xtqqczze force-pushed the clear branch from 63ce50a to 9b15383 Compare March 18, 2026 12:48

Kivooeo approved these changes Mar 18, 2026

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rust-bors bot pushed a commit that referenced this pull request Mar 19, 2026

Auto merge of #154029 - xtqqczze:clear, r=<try>

637b2a9

Replace `truncate(0)` with `clear()`

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Mar 19, 2026

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rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Mar 19, 2026

joboet requested changes Mar 19, 2026

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rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Mar 19, 2026

Replace truncate(0) with clear()

b9cd592

xtqqczze force-pushed the clear branch from 9b15383 to b9cd592 Compare March 19, 2026 13:55

rustbot removed the S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label Mar 19, 2026

rustbot added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Mar 19, 2026

rust-bors bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Mar 28, 2026

RalfJung mentioned this pull request Mar 28, 2026

Rollup of 11 pull requests #154503

Merged

lnicola mentioned this pull request Mar 28, 2026

minor: Replace truncate(0) with clear() rust-lang/rust-analyzer#21898

Merged

rust-bors bot merged commit d289cc4 into rust-lang:main Mar 28, 2026
11 checks passed

rustbot added this to the 1.96.0 milestone Mar 28, 2026

rust-timer added a commit that referenced this pull request Mar 28, 2026

Unrolled build for #154029

8ae848c

Rollup merge of #154029 - xtqqczze:clear, r=joboet Replace `truncate(0)` with `clear()`

xtqqczze deleted the clear branch March 28, 2026 17:10

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xtqqczze commented Mar 18, 2026

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cjgillot commented Mar 19, 2026

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rust-timer commented Mar 19, 2026

Overall result: ✅ improvements - no action needed

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rustbot commented Mar 19, 2026

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xtqqczze commented Mar 19, 2026

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joboet commented Mar 28, 2026

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