more evocative examples for `Sub` and `SubAssign`
These examples are exactly analogous to those in PRs #35709 and #35806. I'll probably remove the `fn main` wrappers for `Add` and `Sub` once this is merged in.
Part of #29365.
r? @steveklabnik
Implement 1581 (FusedIterator)
* [ ] Implement on patterns. See https://github.com/rust-lang/rust/issues/27721#issuecomment-239638642.
* [ ] Handle OS Iterators. A bunch of iterators (`Args`, `Env`, etc.) in libstd wrap platform specific iterators. The current ones all appear to be well-behaved but can we assume that future ones will be?
* [ ] Does someone want to audit this? On first glance, all of the iterators on which I implemented `FusedIterator` appear to be well-behaved but there are a *lot* of them so a second pair of eyes would be nice.
* I haven't touched rustc internal iterators (or the internal rand) because rustc doesn't actually call `fuse()`.
* `FusedIterator` can't be implemented on `std::io::{Bytes, Chars}`.
Closes: #35602 (Tracking Issue)
Implements: rust-lang/rfcs#1581
Implement `CoerceUnsized` for `{Cell, RefCell, UnsafeCell}`
These impls are analogous to the one for `NonZero`. It's occasionally useful to be able to coerce the cell types when they're being used inside another abstraction. See Manishearth/rust-gc#17 for an example.
r? @eddyb
These examples are exactly analogous to those in PRs #35709 and #35806. I'll probably remove the `fn main` wrappers for `Add` and `Sub` once this is merged in.
Part of #29365.
r? @steveklabnik
Carrier trait (third attempt)
This adds a `Carrier` trait to operate with `?`. The only public implementation is for `Result`, so effectively the trait does not exist, however, it ensures future compatibility for the `?` operator. This is not intended to be used, nor is it intended to be a long-term solution.
Although this exact PR has not been through Crater, I do not expect it to be a breaking change based on putting numerous similar PRs though Crater in the past.
cc:
* [? tracking issue](https://github.com/rust-lang/rust/issues/31436)
* [previous PR](https://github.com/rust-lang/rust/pull/35056)
* [RFC issue](https://github.com/rust-lang/rfcs/issues/1718) for discussion of long-term Carrier trait solutions.
r? @nikomatsakis
replace `Add` example with something more evocative of addition
Currently most of the operator traits use trivial implementation
examples that only perform side effects. Honestly, that might not be too
bad for the sake of documentation; but anyway, here's a proposal to move
a slightly modified version of the module-level point-addition example
into the `Add` documentation, since it's more evocative of addition
semantics.
Part of #29365
Part of #29365
explain that std::mem::drop in prelude will invoke Drop
change "prelude" -> "the prelude"; change links to reference-style
move link references to links' section
Currently most of the operator traits use trivial implementation
examples that only perform side effects. Honestly, that might not be too
bad for the sake of documentation; but anyway, here's a proposal to move
a slightly modified version of the module-level point-addition example
into the `Add` documentation, since it's more evocative of addition
semantics.
Part of #29365
wrap identifiers in backticks
minor rephrasing
fix module-level documentation to be more truthful
This branch changes the example for `Add` to no longer be a "minimum implementation that prints something to the screen".
Andrew Paseltiner