add a few more assert_unsafe_precondition

[RalfJung]

Add debug-assertion checking for ptr.read(), ptr.write(_), and unreachable_unchecked.

This is quite useful for cargo-careful.

[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.

Examples of T-libs-api changes:

• Stabilizing library features
• Introducing insta-stable changes such as new implementations of existing stable traits on existing stable types
• Introducing new or changing existing unstable library APIs (excluding permanently unstable features / features without a tracking issue)
• Changing public documentation in ways that create new stability guarantees
• Changing observable runtime behavior of library APIs

[rust-highfive]

r? @joshtriplett

(rust-highfive has picked a reviewer for you, use r? to override)

[RalfJung]

r? libs

[RalfJung]

r? @thomcc

[thomcc]

Thanks! Really wanted the alignment ones the other day!

@bors r+ rollup=iffy

[bors]

📌 Commit 85bf118649b3f32dc795e400d0a28d88d269d1ae has been approved by thomcc

It is now in the queue for this repository.

[bors]

⌛ Testing commit 85bf118649b3f32dc795e400d0a28d88d269d1ae with merge fb3ba99601b5972a9694f4e0ef056ff40b54665b...

[bors]

💔 Test failed - checks-actions

[rustbot]

The Miri subtree was changed

cc @rust-lang/miri

[RalfJung]

@bors r=thomcc

[bors]

📌 Commit d71a851 has been approved by thomcc

It is now in the queue for this repository.

[bors]

⌛ Testing commit d71a851 with merge 3c49830f5329b10c80ddec098e5e378935fbbc05...

[bors]

💥 Test timed out

[RalfJung]

@bors retry timeout on apple-alt

[rust-log-analyzer]

A job failed! Check out the build log: (web) (plain)

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

[bors]

⌛ Testing commit d71a851 with merge 8796e7a...

[bors]

☀️ Test successful - checks-actions
Approved by: thomcc
Pushing 8796e7a to master...

[rust-timer]

Finished benchmarking commit (8796e7a): comparison URL.

Overall result: ❌ regressions - no action needed

@rustbot label: -perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean1	range	count2
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.7%	[0.4%, 1.1%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

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.

	mean1	range	count2
Regressions ❌ (primary)	8.8%	[0.2%, 22.3%]	26
Regressions ❌ (secondary)	2.8%	[2.1%, 3.7%]	3
Improvements ✅ (primary)	-4.8%	[-5.5%, -4.1%]	4
Improvements ✅ (secondary)	-1.5%	[-1.5%, -1.5%]	1
All ❌✅ (primary)	7.0%	[-5.5%, 22.3%]	30

Cycles

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.

	mean1	range	count2
Regressions ❌ (primary)	13.4%	[2.0%, 41.6%]	70
Regressions ❌ (secondary)	8.0%	[2.1%, 15.2%]	22
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	13.4%	[2.0%, 41.6%]	70

Footnotes

1. the arithmetic mean of the percent change ↩ ↩² ↩³

2. number of relevant changes ↩ ↩² ↩³