Lay groundwork for RFC 1422 and improve `PrivateItemsInPublicInterfacesVisitor`
This PR lays groundwork for RFC 1422 (cc #32409) and improves `PrivateItemsInPublicInterfacesVisitor`. More specifically, it
- Refactors away `hir::Visibility::inherit_from`, the semantics of which are obsolete.
- Makes `hir::Visibility` non-`Copy` so that we will be able to add new variants to represent `pub(restricted)` (for example, `Visibility::Restricted(Path)`).
- Adds a new `Copy` type `ty::Visibility` that represents a visibility value, i.e. a characterization of where an item is accessible. This is able to represent `pub(restricted)` visibilities.
- Improves `PrivateItemsInPublicInterfacesVisitor` so that it checks for items in an interface that are less visible than the interface. This fixes#30079 but doesn't change any other behavior.
r? @nikomatsakis
Suggest adding a where-clause when that can help
Suggest adding a where-clause when there is an unmet trait-bound that can be satisfied if some type can implement it.
r? @nikomatsakis
Fix LLVM assert when handling bad intrinsic monomorphizations
Passing an invalid type to certain intrinsics would trigger an LLVM assert even though the invalid type was caught by the compiler.
r? @eddyb
Remove error description of `move`
(1) `x` can be used in main() after the call to spawn(). Because the variables follow normal move semantics, though the keyword `move` is used, and i32 implements `Copy`.
(2) I remove this sentence because the previous sentence gives the referrence to `move closures`, and more description of `move` may be redundant.
Minor doc fixes in "Crates and Modules" and "Lifetimes" chapters
These commits fix a couple of (minor) issues in the _Crates and Modules_ and the _Lifetimes_ chapters of the book.
r? @steveklabnik
Mention that it's not actually a data race
The example can't cause a data race since different indices are accesed.
(perhaps we should use an example where i iterates twice?)
r? @steveklabnik
The AST part of https://github.com/rust-lang/rust/pull/31937
Unlike HIR, AST still uses `Option` for field names because parser can't know field indexes reliably due to constructions like
```
struct S(#[cfg(false)] u8, u8); // The index of the second field changes from 1 during parsing to 0 after expansion.
```
and I wouldn't like to put the burden of renaming fields on expansion passes and syntax extensions.
plugin-[breaking-change] cc https://github.com/rust-lang/rust/issues/31645
r? @Manishearth
[breaking-batch] Add support for `pub(restricted)` syntax in the AST
This PR allows the AST to represent the `pub(restricted)` syntax from RFC 1422 (cc #32409).
More specifically, it makes `ast::Visibility` non-`Copy` and adds two new variants, `Visibility::Crate` for `pub(crate)` and `Visitibility::Restricted { path: P<Path>, id: NodeId }` for `pub(path)`.
plugin-[breaking-change] cc #31645
r? @pnkfelix
1. In the English/Japanese phrases example in the "Multiple File
Crates" section of the "Crates and Modules" chapter, there are a total
of 8 module files that Rust looks for, while only four were
listed. This commit lists all 8 explicitly.
2. Title case fix.
