Move any extra logic that the former had into the latter, so they're consistent.

Fixes rust-lang#42401

Pursuant to issue rust-lang#25663, this commit adds the max and min functions to the Ord trait, enabling items that implement Ord to use UFCS (ex. 1.max(2)) instead of the longer std::cmp::max(1,2) format.

Add docs to librustc/hir/check_attr.rs

Also moved `check_attribute` up to ease reading.

Add overflow checking for `str::get` with inclusive ranges

Fixes rust-lang#42401

Two commits here:

1. The first makes `str::index` just call `SliceIndex<str>::index`.  It's intended to have no behavior change, except where the two methods were inconsistent.
2. The second actually adds the overflow checking to `get(_mut)` (and tests for it)

…=BurntSushi

Add max and min to Ord

Pursuant to issue rust-lang#25663, this PR adds max and min methods with default implementations to std::cmp::Ord. It also modifies std::cmp::max|min to internally alias to Ord::max|min, so that any overrides of the default implementations are automatically used by std::cmp::max|min.

Closes rust-lang#25663

… r=alexcrichton

Capture elapsed duration in Thread::park_timeout example

`beginning_park.elapsed()` might return a larger value within the loop as compared to that checked in the loop conditional.
Since `Duration` arithmetic is checked, hitting such an edge case will cause a panic.

…2, r=eddyb

Add E0617

Part of rust-lang#42229.

cc @Susurrus @frewsxcv @QuietMisdreavus

…al, r=petrochenkov

Possible mistake in lexer rule for octal integer

Original rule allowed for digits 0-8, but octal is 0-7.

The compiler correctly prevents you from placing an 8 in an octal, so I'm assuming this is caught on a later stage. Still, shouldn't the lexer already catch this?