See the inline comments for the description of the new algorithm.

Specifically remove V, which can always be VariantIdx, and F, which can
always be Layout.

Since libctru 2.1.2 was released
(https://github.com/devkitPro/libctru/releases/tag/v2.1.2) we should be
able to use real #[thread_local] without corruption issues on the 3DS
target.

This is required due to `BCryptGenRandom` failing to load the necessary dll on some systems.

rework min_choice algorithm of member constraints

See [this comment](rust-lang#105300 (comment)) for the description of the new algorithm.

Fixes rust-lang#63033
Fixes rust-lang#104639

This uses a more general algorithm than rust-lang#89056 that doesn't treat `'static` as a special case. It thus accepts more code. For example:
```rust
async fn test2<'s>(_: &'s u8, _: &'_ &'s u8, _: &'_ &'s u8) {}
```
I claim it's more correct as well because it fixes rust-lang#104639.

cc ``@nikomatsakis`` ``@lqd`` ``@tmandry`` ``@eholk`` ``@chenyukang`` ``@oli-obk``

r? types

Remove some superfluous type parameters from layout.rs.

Specifically remove V, which can always be VariantIdx, and F, which can always be Layout.

…compiler-errors

Suggest the correct array length on mismatch

Fixes rust-lang#107156

I wasn't able to find a way to get the `Span` for the actual array size unfortunately, so this suggestion can't be applied automatically.

``@rustbot`` label +A-diagnostics

…oli-obk

Handle discriminant in DataflowConstProp

cc ``@jachris``
r? ``@JakobDegen``

This PR attempts to extend the DataflowConstProp pass to handle propagation of discriminants. We handle this by adding 2 new variants to `TrackElem`: `TrackElem::Variant` for enum variants and `TrackElem::Discriminant` for the enum discriminant pseudo-place.

The difficulty is that the enum discriminant and enum variants may alias each another. This is the issue of the `Option<NonZeroUsize>` test, which is the equivalent of rust-lang/unsafe-code-guidelines#84 with a direct write.

To handle that, we generalize the flood process to flood all the potentially aliasing places. In particular:
- any write to `(PLACE as Variant)`, either direct or through a projection, floods `(PLACE as OtherVariant)` for all other variants and `discriminant(PLACE)`;
- `SetDiscriminant(PLACE)` floods `(PLACE as Variant)` for each variant.

This implies that flooding is not hierarchical any more, and that an assignment to a non-tracked place may need to flood a tracked place. This is handled by `for_each_aliasing_place` which generalizes `preorder_invoke`.

As we deaggregate enums by putting `SetDiscriminant` last, this allows to propagate the value of the discriminant.

This refactor will allow to make rust-lang#107009 able to handle discriminants too.

…le-thread-local, r=Nilstrieb

Enable `#[thread_local]` on armv6k-nintendo-3ds

Since [libctru 2.1.2](https://github.com/devkitPro/libctru/releases/tag/v2.1.2)  was released we should now be able to use real `#[thread_local]` without corruption issues on the 3DS target.

CC `@Meziu` `@AzureMarker` `@Techie-Pi`
rust3ds/ctru-rs#91 (comment)

…enkov

Un📦ing the Resolver

r? `@petrochenkov`

pulled out of rust-lang#105462

Revert to using `RtlGenRandom` as a fallback

This is required due to `BCryptGenRandom` failing to load a dll it depends on.

Fixes rust-lang#108059