crates.js should use root_path and not static_root_path

r? `@Nemo157`

Prevent JS error when there is no dependency or other crate documented (or --disable-per-crate-search has been used)

When there is only one crate, the dropdown is removed, creating an error (that you can see pretty easily on docs.rs for example).

r? `@jyn514`

Rollup of 10 pull requests

Successful merges:

 - #81465 (Add documentation about formatting `Duration` values)
 - #82121 (Implement Extend and FromIterator for OsString)
 - #82617 (Document `everybody_loops`)
 - #82789 (Get with field index from pattern slice instead of directly indexing)
 - #82798 (Rename `rustdoc` to `rustdoc::all`)
 - #82804 (std: Fix a bug on the wasm32-wasi target opening files)
 - #82943 (Demonstrate best practice for feeding stdin of a child processes)
 - #83066 (Add `reverse` search alias for Iterator::rev())
 - #83070 (Update cargo)
 - #83081 (Fix panic message of `assert_failed_inner`)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

Fix panic message of `assert_failed_inner`

cc https://github.com/rust-lang/rust/pull/79100#discussion_r593731020

r? ``@m-ou-se``

Update cargo

7 commits in 970bc67c3775781b9708c8a36893576b9459c64a..32da9eaa5de5be241cf8096ca6b749a157194f77
2021-03-07 18:09:40 +0000 to 2021-03-13 01:18:40 +0000
- Fix logic for determining prefer-dynamic for a dylib. (rust-lang/cargo#9252)
- Fix issue with filtering exclusive target dependencies. (rust-lang/cargo#9255)
- Update pkgid-spec docs. (rust-lang/cargo#9249)
- Wordsmith the edition documentation a bit more (rust-lang/cargo#9233)
- Package ID specification urls must contain a host (rust-lang/cargo#9188)
- Add documentation for JSON message_path. (rust-lang/cargo#9247)
- Fix filter_platform to run on targets other than x86. (rust-lang/cargo#9246)

Add `reverse` search alias for Iterator::rev()

When searching for "reverse" in rustdoc you can't find the rev method on Iterator so here is a search alias for that.

Demonstrate best practice for feeding stdin of a child processes

Documentation change.

It's possible to create a deadlock with stdin/stdout I/O on a single thread:

* the child process may fill its stdout buffer, and have to wait for the parent process to read it,
* but the parent process may be waiting until its stdin write finishes before reading the stdout.

Therefore, the parent process should use separate threads for writing and reading.

These examples are not deadlocking in practice, because they use short strings, but I think it's better to demonstrate code that works even for long writes. The problem is non-obvious and tricky to debug (it seems that even libstd has a similar issue: #45572).

This also demonstrates how to use stdio with threads: it's not obvious that `.take()` can be used to avoid fighting with the borrow checker.

I've checked that the modified examples run fine.

std: Fix a bug on the wasm32-wasi target opening files

This commit fixes an issue pointed out in #82758 where LTO changed the
behavior of a program. It turns out that LTO was not at fault here, it
simply uncovered an existing bug. The bindings to
`__wasilibc_find_relpath` assumed that the relative portion of the path
returned was always contained within thee input `buf` we passed in. This
isn't actually the case, however, and sometimes the relative portion of
the path may reference a sub-portion of the input string itself.

The fix here is to use the relative path pointer coming out of
`__wasilibc_find_relpath` as the source of truth. The `buf` used for
local storage is discarded in this function and the relative path is
copied out unconditionally. We might be able to get away with some
`Cow`-like business or such to avoid the extra allocation, but for now
this is probably the easiest patch to fix the original issue.

Rename `rustdoc` to `rustdoc::all`

When rustdoc lints were changed to be tool lints, the `rustdoc` group was removed, leading to spurious warnings like

```
warning: unknown lint: `rustdoc`
```

The lint group still worked when rustdoc ran, since rustdoc added the group itself.

This renames the group to `rustdoc::all` for consistency with `clippy::all` and the rest of the rustdoc lints.

Follow-up to #80527.
r? ``@Manishearth``

Get with field index from pattern slice instead of directly indexing

Closes #82772
r? ``@estebank``

https://github.com/rust-lang/rust/pull/82789#issuecomment-796921977
> ``@estebank`` So the real cause is we only generate single pattern for Box here
https://github.com/csmoe/rust/blob/615b03aeaa8ce9819de7828740ab3cd7def4fa76/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs#L1130-L1132
But in the replacing function, it tries to index on the 1-length pattern slice with field 1, thus out of bounds.
https://github.com/csmoe/rust/blob/615b03aeaa8ce9819de7828740ab3cd7def4fa76/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs#L1346

Document `everybody_loops`

cc `@jyn514`

Implement Extend and FromIterator for OsString

Add the following trait impls:

- `impl Extend<OsString> for OsString`
- `impl<'a> Extend<&'a OsStr> for OsString`
- `impl FromIterator<OsString> for OsString`
- `impl<'a> FromIterator<&'a OsStr> for OsString`

Because `OsString` is a platform string with no particular semantics, concatenating them together seems acceptable.

I came across a use case for these trait impls in https://github.com/artichoke/artichoke/pull/1089:

Artichoke is a Ruby interpreter. Its CLI accepts multiple `-e` switches for executing inline Ruby code, like:

```console
$ cargo -q run --bin artichoke -- -e '2.times {' -e 'puts "foo: #{__LINE__}"' -e '}'
foo: 2
foo: 2
```

I use `clap` for command line argument parsing, which collects these `-e` commands into a `Vec<OsString>`. To pass these commands to the interpreter for `Eval`, I need to join them together. Combining these impls with `Iterator::intersperse` https://github.com/rust-lang/rust/issues/79524 would enable me to build a single bit of Ruby code.

Currently, I'm doing something like:

```rust
let mut commands = commands.into_iter();
let mut buf = if let Some(command) = commands.next() {
    command
} else {
    return Ok(Ok(()));
};
for command in commands {
    buf.push("\n");
    buf.push(command);
}
```

If there's interest, I'd also like to add impls for `Cow<'a, OsStr>`, which would avoid allocating the `"\n"` `OsString` in the concatenate + intersperse use case.

Add documentation about formatting `Duration` values

Explain why Duration has a Debug impl but not a Display impl, and
mention the use of Unicode.

Explain why Duration has a Debug impl but not a Display impl, and
mention the use of Unicode.

Tweaks to stable hashing

Turn `-Z incremental-verify-ich` on by default

Issue #82920 showed that the kind of bugs caught by this flag have
soundness implications.

Issue #82920 showed that the kind of bugs caught by this flag have
soundness implications.

This causes performance regressions of up to 15.2% during incremental
compilation, but this is necessary to catch miscompilations caused by
bugs in query implementations.

rustc_query_system: simplify QueryCache::iter

Minor cleanup to reduce a small amount of complexity and code bloat.
Reduces the number of mono items in rustc_query_impl by 15%.

Make def_key and HIR parenting consistent.

r? `@petrochenkov`

2229: Handle capturing a reference into a repr packed struct

RFC 1240 states that it is unsafe to capture references into a
packed-struct. This PR ensures that when a closure captures a precise
path, we aren't violating this safety constraint.

To acheive so we restrict the capture precision to the struct itself.

An interesting edge case where we decided to restrict precision:
```rust
struct Foo(String);

let foo: Foo;
let c = || {
    println!("{}", foo.0);
    let x = foo.0;
}
```

Given how closures get desugared today, foo.0 will be moved into the
closure, making the `println!`, safe. However this can be very subtle
and also will be unsafe if the closure gets inline.

Closes: https://github.com/rust-lang/project-rfc-2229/issues/33

r? `@nikomatsakis`

Fix leak in Vec::extend_from_within

Fixes #82533

Allow calling *const methods on *mut values

This allows `*const` methods to be called on `*mut` values.

TODOs:

- [x] ~~Remove debug logs~~ Done.
- [x] ~~I haven't tested, but I think this currently won't work when the `self` value has type like `&&&&& *mut X` because I don't do any autoderefs when probing. To fix this the new code in `rustc_typeck::check::method::probe` needs to reuse `pick_method` somehow as I think that's the function that autoderefs.~~ This works, because autoderefs are done before calling `pick_core`, in `method_autoderef_steps`, called by `probe_op`.
- [x] ~~I should probably move the new `Pick` to `pick_autorefd_method`. If not, I should move it to its own function.~~ Done.
- [ ] ~~Test this with a `Pick` with `to_ptr = true` and `unsize = true`.~~ I think this case cannot happen, because we don't have any array methods with `*mut [X]` receiver. I should confirm that this is true and document this. I've placed two assertions about this.
- [x] ~~Maybe give `(Mutability, bool)` a name and fields~~ I now have a `to_const_ptr` field in `Pick`.
- [x] ~~Changes in `adjust_self_ty` is quite hacky. The problem is we can't deref a pointer, and even if we don't have an adjustment to get the address of a value, so to go from `*mut` to `*const` we need a special case.~~ There's still a special case for `to_const_ptr`, but I'm not sure if we can avoid this.
- [ ] Figure out how `reached_raw_pointer` stuff is used. I suspect only for error messages.

Fixes #80258

Rollup of 6 pull requests

Successful merges:

 - #82984 (Simplify ast block lowering)
 - #83012 (Update Clippy)
 - #83020 (Emit the enum range assumption if the range only contains one element)
 - #83037 (Support merge_functions option in NewPM since LLVM >= 12)
 - #83052 (updated vulnerable deps)
 - #83059 (Allow configuring `rustdoc --disable-minification` in config.toml)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

Minor cleanup to reduce a small amount of complexity and code bloat.
Reduces the number of mono items in rustc_query_impl by 15%.

Allow configuring `rustdoc --disable-minification` in config.toml

This way, you can debug rustdoc's JavaScript and CSS file with normal F12 Dev Tools and you'll have useful line numbers to work with.

updated vulnerable deps

* Updated signal-hook-registry 1.2.1 to 1.2.2, as it drops dependency on vulnerable arc-swap 0.4.7 https://rustsec.org/advisories/RUSTSEC-2020-0091
* Updated generic-array 0.12.3 to 0.12.4, vuln https://rustsec.org/advisories/RUSTSEC-2020-0146
* Updated sized-chunks 0.6.2 to 0.6.4, vuln https://rustsec.org/advisories/RUSTSEC-2020-0041 fixed in 0.6.3, in 0.6.4 fixed some UB https://github.com/bodil/sized-chunks/blob/master/CHANGELOG.md#064---2021-02-17

Support merge_functions option in NewPM since LLVM >= 12

now we can pass this flag since https://reviews.llvm.org/D93002 has been merged.

Emit the enum range assumption if the range only contains one element

close https://github.com/rust-lang/rust/issues/82871

Update Clippy

Bi-weekly Clippy sync.

r? ``@Manishearth``

Simplify ast block lowering

Don't implement mem::replace with mem::swap.

`swap` is a complicated operation, so this changes the implementation of `replace` to use `read` and `write` instead.

See https://github.com/rust-lang/rust/pull/83019.

I wrote there:

> Implementing the simpler operation (replace) with the much more complicated operation (swap) doesn't make a whole lot of sense. `replace` is just read+write, and the primitive for moving out of a `&mut`. `swap` is for doing that to *two* `&mut` at the same time, which is both more niche and more complicated (as shown by `swap_nonoverlapping_bytes`).

This could be especially interesting for `Option<VeryLargeStruct>::take()`, since swapping such a large structure with `swap_nonoverlapping_bytes` is going to be much less efficient than `ptr::write()`'ing a `None`.

But also for small values where `swap` just reads/writes using temporary variable, this makes a `replace` or `take` operation simpler:
![image](https://user-images.githubusercontent.com/783247/110839393-c7e6bd80-82a3-11eb-97b7-28acb14deffd.png)