Do not use box syntax in std

[joboet]

See #94970 and #49733. About half of the box instances in std do not even need to allocate, the other half can simply be replaced with Box::new.

@rustbot label +T-libs
r? rust-lang/libs

[rustbot]

Hey! It looks like you've submitted a new PR for the library teams!

If this PR contains changes to any rust-lang/rust public library APIs then please comment with @rustbot label +T-libs-api -T-libs to tag it appropriately. If this PR contains changes to any unstable APIs please edit the PR description to add a link to the relevant API Change Proposal or create one if you haven't already. If you're unsure where your change falls no worries, just leave it as is and the reviewer will take a look and make a decision to forward on if necessary.

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• Changing observable runtime behavior of library APIs

[thomcc]

At one point this had perf implications. Seems highly unlikely for this patch, but measuring can't hurt.

@bors try @rust-timer queue

[bors]

⌛ Trying commit 7f2cf19 with merge 0610c4d3402a5128c3b2bb5d074c332197053e14...

[bors]

☀️ Try build successful - checks-actions
Build commit: 0610c4d3402a5128c3b2bb5d074c332197053e14 (0610c4d3402a5128c3b2bb5d074c332197053e14)

[rust-timer]

Finished benchmarking commit (0610c4d3402a5128c3b2bb5d074c332197053e14): comparison URL.

Overall result: no relevant changes - no action needed

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

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

Instruction count

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

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	2.4%	[2.4%, 2.4%]	1
Improvements ✅ (primary)	-1.5%	[-2.3%, -0.7%]	2
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-1.5%	[-2.3%, -0.7%]	2

Cycles

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

[thomcc]

Sorry for the delay. You also rewrote a bunch of code at the same time, which complicated review (in the future, it would be better for those to be separate PRs, TBH).

@bors r+

[bors]

📌 Commit 7f2cf19 has been approved by thomcc

It is now in the queue for this repository.

[bors]

⌛ Testing commit 7f2cf19 with merge d3322e2...

[bors]

☀️ Test successful - checks-actions
Approved by: thomcc
Pushing d3322e2 to master...

[rust-timer]

Finished benchmarking commit (d3322e2): 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)

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

Cycles

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