Use Expr instead. Use `ExprKind::Let` to represent if let guards.

Use Expr instead. Use `ExprKind::Let` to represent if let guards.

Match guards with an if let guard or an if let chain guard should have a
temporary scope of the whole arm. This is to allow ref bindings to
temporaries to borrow check.

…er-errors

Add support for shell argfiles

Closes rust-lang/compiler-team#684

…den-suggest, r=davidtwco

Hide foreign `#[doc(hidden)]` paths in import suggestions

Stops the compiler from suggesting to import foreign `#[doc(hidden)]` paths.

``@rustbot`` label A-suggestion-diagnostics

…nds, r=compiler-errors

Imply outlives-bounds on lazy type aliases

Fixes rust-lang#118479.

r? types

…mpiler-errors

Make `negative_bounds` internal & fix some of its issues

r? compiler-errors

…bject-safety-error, r=Nilstrieb

Use `resolutions(()).effective_visiblities` to avoid cycle errors in `report_object_error`

Inside of `report_object_error`, using the `effective_visibilities` query causes cycles since it calls `type_of`, which itself may call `typeck`, which may end up reporting its own object-safety errors.

Fixes rust-lang#119346
Fixes rust-lang#119502

…tion, r=compiler-errors

Fix scoping for let chains in match guards

If let guards were previously represented as a different type of guard in HIR and THIR. This meant that let chains in match guards were not handled correctly because they were treated exactly like normal guards.

- Remove `hir::Guard` and `thir::Guard`.
- Make the scoping different between normal guards and if let guards also check for let chains.

closes rust-lang#118593

…r=oli-obk

Check yield terminator's resume type in borrowck

In borrowck, we didn't check that the lifetimes of the `TerminatorKind::Yield`'s `resume_place` were actually compatible with the coroutine's signature. That means that the lifetimes were totally going unchecked. Whoops!

This PR implements this checking.

Fixes rust-lang#119564

r? types

…ulacrum

cstore: Remove unnecessary locking from `CrateMetadata`

Locks and atomics in `CrateMetadata` fields were necessary before rust-lang#107765 when `CStore` was cloneable, but now they are not necessary and can be removed after restructuring the code a bit to please borrow checker.

All remaining locked fields in `CrateMetadata` are lazily populated caches.