Extend support for `implies_by` (from `#[stable]` and `#[unstable]`)
to `#[rustc_const_stable]` and `#[rustc_const_unstable]`.

Signed-off-by: David Wood <[email protected]>

Desugaring DropAndReplace at MIR build (rust-lang#107844) fixed issue
70919. Add regressions tests, borrowed from rust-lang#102078, to ensure we
check for this in the future.

Co-authored-by: Aaron Hill <[email protected]>

… r=Nilstrieb

const_eval: `implies_by` in `rustc_const_unstable`

Fixes rust-lang#107605.

Extend support for `implies_by` (from `#[stable]` and `#[unstable]`) to `#[rustc_const_stable]` and `#[rustc_const_unstable]`.

cc ``@steffahn``

Fix `ObligationCtxt::sub`

typo it seems

Add regression tests for issue 70919

Desugaring DropAndReplace at MIR build (rust-lang#107844) fixed rust-lang#70919.
Add regressions tests, borrowed from rust-lang#102078, to ensure we check for this in the future.

cc ``@Aaron1011``

…-obk

Check for free regions in MIR validation

This turns rust-lang#108720 into a MIR validation failure that will reproduce without debug-assertions enabled.

```
error: internal compiler error: broken MIR in Item(WithOptConstParam { did: DefId(0:296 ~ futures_util[3805]::future::future::remote_handle::{impl#3}::poll), const_param_did: None }) (after pass ScalarReplacementOfAggregates) at bb0[0]:
                                Free regions in optimized runtime-post-cleanup MIR
  --> /home/ben/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/futures-util-0.3.26/src/future/future/remote_handle.rs:96:13
   |
96 |         let this = self.project();
   |             ^^^^
```

Do not ICE when interpreting a cast between non-monomorphic types

Fixes rust-lang#101596

…li-obk

Do not ICE when failing to normalize in ConstProp.

There is no reason to delay a bug there, as we bubble up the failure as TooGeneric.

Fixes rust-lang#97728

…t_impls, r=lcnr

Emit the suspicious_auto_trait_impls for negative impls as well

Fixes rust-lang#108804

…rieb

Add regression test for rust-lang#98444

cc rust-lang#108730 this will need to be changed to a `check-fail` test once it lands.

Fixes rust-lang#98444