Use this to simplify the object safety code a bit.

update Miri

With https://github.com/rust-lang/rust/pull/63404 landed, we need https://github.com/rust-lang/miri/pull/898 to avoid failures in https://github.com/RalfJung/miri-test-libstd.

r? @oli-obk

diagnostics: Describe crate root modules in `DefKind::Mod` as "crate"

Or we can use "extern crate" like resolve previously did sometimes, not sure.

r? @davidtwco

rustdoc: general cleanups

This is purely a refactoring, mostly just simplifying some of the code. Commits are best reviewed individually.

Rollup of 4 pull requests

Successful merges:

 - #63400 (Try to break resolve into more isolated parts)
 - #63425 (Cleanup historical stability comments)
 - #63429 (.gitignore: Readd `/tmp/`)
 - #63432 (Cleanup & Simplify stuff in lowering)

Failed merges:

r? @ghost

Cleanup & Simplify stuff in lowering

Closes https://github.com/rust-lang/rust/issues/60253 as a byproduct.

It turns out that it is in fact necessary to have a `DropTemps(...)` around the `match_expr` and there is a test (https://github.com/rust-lang/rust/blob/master/src/test/ui/issues/issue-13304.rs) which fails without that.

r? @EddyB

.gitignore: Readd `/tmp/`

Specifically, `/tmp/partitioning-tests/` it is generated by the incremental tests, https://github.com/rust-lang/rust/search?p=2&q=partitioning-tests&unscoped_q=partitioning-tests. These are cleaned up by compiletest but not if you kill testing prematurely (which I just did to test out a rollup, and it is annoying to `rm -rf tmp/`).

r? @Mark-Simulacrum
cc @RalfJung

Cleanup historical stability comments

These weren't removed by ccbcc720 most likely by accident,
let's clean them up now.

Try to break resolve into more isolated parts

Some small step towards resolve librarification.

"Late resolution" is the pass that resolves most of names in a crate beside imports and macros.
It runs when the crate is fully expanded and its module structure is fully built.
So we just walk through the crate and resolve all the expressions, types, etc.

This pass is pretty self-contained, but it was previously done by implementing `Visitor` on the whole `Resolver` (which is used for many other tasks), and fields specific to this pass were indiscernible from the global `Resolver` state.

This PR moves the late resolution pass into a separate visitor and a separate file, fields specific to this visitor are moved from `Resolver` as well.

I'm especially happy about `current_module` being removed from `Resolver`.
It was used even for operations not related to visiting and changing the `current_module` position in process.
It was also used as an implicit argument for some functions used in this style
```rust
let orig_current_module = mem::replace(&mut self.current_module, module);
self.resolve_ident_somewhere();
self.current_module = orig_current_module;
```
and having effects on e.g. privacy checking somewhere deeply inside `resolve_ident_somewhere`.
Now we explicitly pass a `ParentScope` to those functions instead, which includes the module and some other data describing our position in the crate relatively to which we resolve names.

Rustdoc was one of the users of `current_module`, it set it for resolving intra-doc links.
Now it passes it explicitly as an argument as well (I also supported resolving paths from rustdoc in unnamed blocks as a drive-by fix).

Visibility resolution is also changed to use early resolution (which is correct because it's used during the work of `BuildReducedGraphVisitor`, i.e. integration of a new AST fragment into the existing partially built module structures.) instead of untimely late resolution (which worked only due to restrictions on paths in visibilities like inability to refer to anything except ancestor modules).
This slightly regresses its diagnostics because late resolution has a more systematic error detection and recovery currently.
Due to changes in `current_module` and visibilities `BuildReducedGraphVisitor` ended up almost as heavily affected by this refactoring as late resolution.

Fixes https://github.com/rust-lang/rust/issues/63223 (due to visibility resolution changes).

Also privatizes needlessly public methods to enforce which methods
callers are intended to call, i.e., only `new` and `visit`.

Previously visit could be called multiple times, but this is inaccurate,
as it deconstructs Visitor state.

Make the `is_import` flag in `ScopeSet` independent from namespace
Fix rebase

Cleanup some surrounding code.
Support resolution of intra doc links in unnamed block scopes.
(Paths from rustdoc now use early resolution and no longer need results of late resolution like all the built ribs.)

Fix one test hitting file path limits on Windows.

Move methods logically belonging to build-reduced-graph into `impl BuildReducedGraphVisitor` and `build_reduced_graph.rs`
Move types mostly specific to late resolution closer to the late resolution visitor

Rename it to `report_error` and move into `diagnostics.rs`

Also turn `check_unused` into a method on `Resolver`

It's now immediately clear what fields belong to the global resolver state and what are specific to passes/visitors.

Instead of tracking current module and other components separately.
(`ParentScope` includes the module as a component.)

Move `Resolver` fields specific to late resolution to the new visitor.
The `current_module` field from `Resolver` is replaced with two `current_module`s in `LateResolutionVisitor` and `BuildReducedGraphVisitor`.
Outside of those visitors `current_module` is replaced by passing `parent_scope` to more functions and using the parent module from it.

Visibility resolution no longer have access to later resolution methods and has to use early resolution, so its diagnostics in case of errors regress slightly.

Sort the fat LTO modules to produce deterministic output.

Some projects that use LTO for their release builds are not reproducible.  We can fix this by sorting the fat LTO modules before using them.

It might also be useful to do this for thin LTO, but I couldn't get that to work to test it so I didn't do it.

It is produced during `./x.py test`

Rollup of 7 pull requests

Successful merges:

 - #63056 (Give built-in macros stable addresses in the standard library)
 - #63337 (Tweak mismatched types error)
 - #63350 (Use associated_type_bounds where applicable - closes #61738)
 - #63394 (Add test for issue 36804)
 - #63399 (More explicit diagnostic when using a `vec![]` in a pattern)
 - #63419 (check against more collisions for TypeId of fn pointer)
 - #63423 (Mention that tuple structs are private if any of their fields are)

Failed merges:

r? @ghost

Mention that tuple structs are private if any of their fields are

CC #39703

check against more collisions for TypeId of fn pointer

Cc https://github.com/rust-lang/rfcs/pull/2738#issuecomment-519923318

More explicit diagnostic when using a `vec![]` in a pattern

```
error: unexpected `(` after qualified path
  --> $DIR/vec-macro-in-pattern.rs:3:14
   |
LL |         Some(vec![x]) => (),
   |              ^^^^^^^
   |              |
   |              unexpected `(` after qualified path
   |              in this macro invocation
   |              use a slice pattern here instead
   |
   = help: for more information, see https://doc.rust-lang.org/edition-guide/rust-2018/slice-patterns.html
   = note: this warning originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
```

Fix #61933.