Refocus unsafe code chapter on unsafe itself.

[steveklabnik]

#24631 is related, as it will delete this from the TOC, but I want to keep it here.

[rust-highfive]

r? @brson

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[brson]

@bors r+ rollup

[bors]

📌 Commit e7111e7 has been approved by brson

[huonw]

s/arne/aren/

[huonw]

I assume you're intending to spread the content here into other sections?

I feel like having a focused sub-guide for unsafe code (i.e. some organisation beyond just a pile of chapters mixed in with the rest of Syntax and Semantics or whatever) is useful: it is hard enough to write unsafe code already, and scattering the documentation about gotchas and best practices (for unsafe, raw pointers, ...) doesn't seem like it will help.

Maybe the organisation could be using this section as a landing page that links to all the other related sections?

[bors]

⌛ Testing commit e7111e7 with merge a3bb026...

[bors]

💔 Test failed - auto-win-32-nopt-t

[steveklabnik]

@bors: r=brson rollup

[bors]

📌 Commit e7111e7 has been approved by brson

[steveklabnik]

@huonw yes, a "Writing Safe Abstractions" chapter would be awesome in Effective Rust, but after moving most of what was in the unsafe guide to the unstable section, looking at this chapter, there's basically raw pointer stuff, and some comments about making unsafe things safer. In the new, semantics-oriented layout of these chapters, raw pointers deserve their own intro, and so does unsafe.

[steveklabnik]

@bors: r=brson rollup

[bors]

📌 Commit 9cc0af8 has been approved by brson

[huonw]

@steveklabnik as long as you have a plan! (That plan sounds good to me.)