Previously it failed on Windows if the file had the `FILE_ATTRIBUTE_HIDDEN` attribute set. This was inconsistent with `OpenOptions::new().write(true).truncate(true)` which can truncate an existing hidden file.

The new flag has been described in the Major Change Proposal at
rust-lang/compiler-team#656

The instance evaluation is needed to handle intrinsics such as
`type_id` and `type_name`.

Since we now use Allocation to represent all evaluated constants,
provide a few methods to help process the data inside an allocation.

detects redundant imports that can be eliminated.

for rust-lang#117772 :

In order to facilitate review and modification, split the checking code and
removing redundant imports code into two PR.

as they unnecessarily clutter the diagnostic output and make the
experience of adding a new target to the compiler more painful than
it should be.

target_os and target_arch are still being tested in the
well-known-values.rs test, but in one place.

Windows: Allow `File::create` to work on hidden files

This makes `OpenOptions::new().write(true).create(true).truncate(true).open(&path)` work if the path exists and is a hidden file. Previously it would fail with access denied.

This makes it consistent with `OpenOptions::new().write(true).truncate(true).open(&path)` (note the lack of `create`) which does not have this restriction. It's also more consistent with other platforms.

Fixes rust-lang#115745 (see that issue for more details).

…workingjubilee

Implement repr(packed) for repr(simd)

This allows creating vectors with non-power-of-2 lengths that do not have padding.  See rust-lang/portable-simd#319

…ty, r=TaKO8Ki

Add unstable `-Zdefault-hidden-visibility` cmdline flag for `rustc`.

The new flag has been described in the Major Change Proposal at
rust-lang/compiler-team#656

…-dead

Fix const drop checking

Fixes confirmation of `~const Destruct` and const drops.

r? fee1-dead

…petrochenkov

remove redundant imports

detects redundant imports that can be eliminated.

for rust-lang#117772 :

In order to facilitate review and modification, split the checking code and removing redundant imports code into two PR.

r? ``@petrochenkov``

Add instance evaluation and methods to read an allocation in StableMIR

The instance evaluation is needed to handle intrinsics such as `type_id` and `type_name`.

Since we now use Allocation to represent all evaluated constants, provide a few methods to help process the data inside an allocation.

I've also started to add a structured way to get information about the compilation target machine. For now, I've only added information needed to process an allocation.

r? ``@ouz-a``

…own, r=nnethercote

Strengthen well known check-cfg names and values test

rust-lang#118494 is changing the implementation of how we expect well known check-cfg names and values, but we currently don't have a test that checks every well known only some of them.

This PR therefore strengthen our well known names/values test to include all of the configs to at least avoid unintended regressions and validate new entry.

*this PR also contains some drive-by consolidation of unexpected `target_os`, `target_arch` into a single file*

r? `@nnethercote` (maybe? feel free to re-assign)