Update emscripten std tests
This disables a bunch of emscripten tests that test things emscripten doesn't support and re-enables a whole bunch of tests which now work just fine on emscripten.
Tested with `EMCC_CFLAGS="-s MAXIMUM_MEMORY=2GB" ./x.py test library/ --target wasm32-unknown-emscripten`.
Fix `FormattingOptions` instantiation with `Default`
The `fill` value by default should be set to `' '` (space), but the current implementation uses `#[derive(Default)]` which sets it to `\0`.
Note that `FormattingOptions` is being released as part of 1.85 (unstable) - so this might warrant a backport to that branch.
Tracking issue: https://github.com/rust-lang/rust/issues/118117
Follow up from https://github.com/rust-lang/rust/pull/118159
CC: ``@EliasHolzmann`` ``@programmerjake``
r? ``@m-ou-se``
Add memory layout documentation to generic NonZero<T>
The documentation I've added is based on the same Layout documentation that appears on the other `NonZero*` types. For example see [the Layout docs on `NonZeroI8`](https://doc.rust-lang.org/std/num/type.NonZeroI8.html#layout-1).
remove pointless allowed_through_unstable_modules on TryFromSliceError
This got added in https://github.com/rust-lang/rust/pull/132482 but the PR does not explain why. `@lukas-code` do you still remember? Also Cc `@Noratrieb` as reviewer of that PR.
If I understand the issue description correctly, all paths under which this type is exported are stable now: `core::array::TryFromSliceError` and `std::array::TryFromSliceError`. If that is the case, we shouldn't have the attribute; it's a terrible hack that should only be used when needed to maintain backward compatibility. Getting some historic information right is IMO *not* sufficient justification to risk accidentally exposing this type via more unstable paths today or in the future.
Implement `ByteStr` and `ByteString` types
Approved ACP: https://github.com/rust-lang/libs-team/issues/502
Tracking issue: https://github.com/rust-lang/rust/issues/134915
These types represent human-readable strings that are conventionally,
but not always, UTF-8. The `Debug` impl prints non-UTF-8 bytes using
escape sequences, and the `Display` impl uses the Unicode replacement
character.
This is a minimal implementation of these types and associated trait
impls. It does not add any helper methods to other types such as `[u8]`
or `Vec<u8>`.
I've omitted a few implementations of `AsRef`, `AsMut`, and `Borrow`,
when those would be the second implementation for a type (counting the
`T` impl), to avoid potential inference failures. We can attempt to add
more impls later in standalone commits, and run them through crater.
In addition to the `bstr` feature, I've added a `bstr_internals` feature
for APIs provided by `core` for use by `alloc` but not currently
intended for stabilization.
This API and its implementation are based *heavily* on the `bstr` crate
by Andrew Gallant (`@BurntSushi).`
r? `@BurntSushi`
Add an example of using `carrying_mul_add` to write wider multiplication
Just the basic quadratic version that you wouldn't actually use for really-big integers, but it's nice and short so is useful as for a demonstration of why you might find `carrying_mul_add` useful :)
cc #85532 ``````@clarfonthey``````
Enable `unreachable_pub` lint in core
This PR enables the [`unreachable_pub`](https://doc.rust-lang.org/rustc/lints/listing/allowed-by-default.html#unreachable-pub) as warn in `core`, `rtstartup` and `panic_unwind`.
The motivation is similar to the compiler [MCP: Enable deny(unreachable_pub) on `rustc_*` crates](https://github.com/rust-lang/compiler-team/issues/773#issue-2467219005) :
> "Where is this thing used?" is a question I ask all the time when reading unfamiliar code. Because of this, I generally find it annoying when things are marked with a more permissive visibility than necessary. "This thing marked pub, which other crates is it used in? Oh, it's not used in any other crates."
Another motivation is to help to lint by utilizing it in-tree and seeing it's limitation in more complex scenarios.
The diff was mostly generated with `./x.py fix --stage 1 library/core/ -- --broken-code`, as well as manual edits for code in macros, generated code and other targets.
r? libs
Reexport likely/unlikely in std::hint
Since `likely`/`unlikely` should be working now, we could reexport them in `std::hint`. I'm not sure if this is already approved or if it requires approval
Tracking issue: #26179
Improve `select_nth_unstable` documentation clarity
* Instead uses `before` and `after` variable names in the example
where `greater` and `lesser` are flipped.
* Uses `<=` and `>=` instead of "less than or equal to" and "greater
than or equal to" to make the docs more concise.
* General attempt to remove unnecessary words and be more precise. For
example it seems slightly wrong to say "its final sorted position",
since this implies there is only one sorted position for this element.
