This change makes it so, instead of mixing string distance with
type unification, function signature search works by
mapping names to IDs at the start, reporting to the user any
cases where it had to make corrections, and then matches with
IDs when going through the items.

This only changes function searches. Name searches are left alone,
and corrections are only done when there's a single item in the
search query.

Because we're writing to a file, so `FileEncoder` is better because we
don't have to write all the data to memory first.

The suggestion given by `FIXME` to use `CompilerMetadata` for
`download_toolchain` in `bootstrap::download` can result in more
confusion. This is because `stamp_key` is not always a date; it
can also be a commit hash. Additionally, unlike in `download_beta_toolchain`,
in the `download_ci_rustc` function, `version` and `commit` values
are calculated separately.

Signed-off-by: ozkanonur <work@onurozkan.dev>

Because it then just has to be filtered out.

This change makes this test more like these other tests:
- tests/ui/treat-err-as-bug/err.rs
- tests/ui/treat-err-as-bug/delay_span_bug.rs
- tests/ui/mir/validate/storage-live.rs
- tests/ui/associated-inherent-types/bugs/ice-substitution.rs
- tests/ui/layout/valid_range_oob.rs

This test is supposed to ensure that full backtraces are used for ICEs.
But it doesn't actually do that -- the filtering done cannot distinguish
between a full backtrace versus a short backtrace.

So this commit changes the filtering to preserve the existence of
`__rust_{begin,end}_short_backtrace` markers, which only appear in full
backtraces. This change means the test now tests what it is supposed to
test.

Also, the existing filtering included a rule that excluded any line
starting with two spaces. This was too strong because it filtered out
some parts of the error message. (This was not a showstopper). It was
also not strong enough because it didn't work with three digit stack
frame numbers, which just started seeing after upgrading my Ubuntu
distro to 23.04 machine (this *was* a showstopper).

So the commit replaces that rule with two more precise rules, one for
lines with stack frame numbers, and one for "at ..." lines.

Round-trip encoding/decoding of many types is tested in
`compiler/rustc_serialize/tests/opaque.rs`. There is also a small amount
of encoding/decoding testing in three files in `tests/ui-fulldeps`.

There is no obvious reason why these three files are necessary. They
were originally added in 2014. Maybe it wasn't possible for a proc
macro to run in a unit test back then?

This commit just moves the testing from those three files into the unit
test.

It's only used in tests. Which is bad, because it means that
`FileEncoder` is used in the compiler but isn't used in tests!

`tests/opaque.rs` now tests encoding/decoding round-trips via file.
Because this is slower than memory, this commit also adjusts the
`u16`/`i16` tests so they are more like the `u32`/`i32` tests, i.e. they
don't test every possible value.

I don't like the current wording. It's obnoxious to be told by a bot
that a change I made intentionally is "probably unintentional"! I also
don't like describing unintentional changes as "Random", it's not the
right word.

…ister,wesleywiser

Stabilize raw-dylib, link_ordinal, import_name_type and -Cdlltool

This stabilizes the `raw-dylib` feature (rust-lang#58713) for all architectures (i.e., `x86` as it is already stable for all other architectures).

Changes:
* Permit the use of the `raw-dylib` link kind for x86, the `link_ordinal` attribute and the `import_name_type` key for the `link` attribute.
* Mark the `raw_dylib` feature as stable.
* Stabilized the `-Zdlltool` argument as `-Cdlltool`.
* Note the path to `dlltool` if invoking it failed (we don't need to do this if `dlltool` returns an error since it prints its path in the error message).
* Adds tests for `-Cdlltool`.
* Adds tests for being unable to find the dlltool executable, and dlltool failing.
* Fixes a bug where we were checking the exit code of dlltool to see if it failed, but dlltool always returns 0 (indicating success), so instead we need to check if anything was written to `stderr`.

NOTE: As previously noted (rust-lang#104218 (comment)) using dlltool within rustc is temporary, but this is not the first time that Rust has added a temporary tool use and argument: rust-lang#104218 (comment)

Big thanks to `````@tbu-````` for the first version of this PR (rust-lang#104218)

…ions, r=GuillaumeGomez

rustdoc: restructure type search engine to pick-and-use IDs

Fixes rust-lang#110029

Preview: https://notriddle.com/rustdoc-demo-html-3/search-corrections/std/index.html?search=-%3E%20streaming

![image](https://user-images.githubusercontent.com/1593513/233494900-ae77d5b4-e395-41f8-bbac-53ee55bb4a76.png)

This change makes it so, instead of mixing string distance with type unification, function signature search works by mapping names to IDs at the start, reporting to the user any cases where it had to make corrections, and then matches with IDs when going through the items.

This only changes function searches. Name searches are left alone, and corrections are only done when there's a single item in the search query.

…-errors

resolve: One more attempt to simplify `module_children`

If the next step is performed and `fn module_children_local` is merged with the `module_children` query, then it causes perf regressions, regardless of whether query result feeding is [used](https://perf.rust-lang.org/compare.html?start=43a78029b4f4d92978b8fde0a677ea300b113c41&end=2eb5bcc5068b9d92f74bcb1797da664865d6981d&stat=instructions:u) or [not](https://perf.rust-lang.org/compare.html?start=2fce2290865f012391b8f3e581c3852a248031fa&end=2a33d6cd99481d1712037a79e7d66a8aefadbf72&stat=instructions:u).

avoid duplicating TLS state between test std and realstd

This basically re-lands rust-lang#100201 and rust-lang#106638, which got reverted by rust-lang#110861. This works around 2 Miri limitations:
- Miri doesn't support the magic linker section that our Windows TLS support relies on, and instead knows where in std to find the symbol that stores the thread callback.
- For macOS, Miri only supports at most one destructor to be registered per thread.

The 2nd would not be very hard to fix (though the intended destructor order is unclear); the first would be a lot of work to fix. Neither of these is a problem for regular Rust code, but in the std test suite we have essentially 2 copies of the std code and then these both become issues. To avoid that we have the std test crate import the TLS code from the real std instead of having its own copy.

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

…t, r=tmiasko

Encode def span for foreign return-position `impl Trait` in trait

Fixes rust-lang#111031, yet another def-span encoding issue :/

Includes a smaller repro than the issue, but I can confirm it ICEs:

```
query stack during panic:
#0 [def_span] looking up span for `rpitit::Foo::bar::{opaque#0}`
#1 [object_safety_violations] determining object safety of trait `rpitit::Foo`
rust-lang#2 [check_is_object_safe] checking if trait `rpitit::Foo` is object safe
rust-lang#3 [typeck] type-checking `main`
rust-lang#4 [used_trait_imports] finding used_trait_imports `main`
rust-lang#5 [analysis] running analysis passes on this crate
```

Luckily since this only affects nightly, this desn't need to be backported.

Fix problems with backtraces in two ui tests.

`default-backtrace-ice.rs` started started failing for me recently,
because on my Ubuntu 23.04 system there are 100 stack frames, and the
current stack filtering pattern doesn't match on a stack frame with a
three digit number.

`issue-86800.rs` can also be improved, backtrace-wise.

r? ```@Nilstrieb```

…r=albertlarsan68

remove pointless `FIXME` in `bootstrap::download`

The suggestion given by `FIXME` to use `CompilerMetadata` for `download_toolchain` in `bootstrap::download` can result in more confusion. This is because `stamp_key` is not always a date; it can also be a commit hash. Additionally, unlike in `download_beta_toolchain`, in the `download_ci_rustc` function, `version` and `commit` values are calculated separately.

Remove `MemEncoder`

`MemEncoder` only has one non-test use, and `FileEncoder` would be more appropriate there anyway.

r? `@cjgillot`

…mpiler-errors

check array type of repeat exprs is wf

Fixes rust-lang#111091

Also makes sure that we actually renumber regions in the length of repeat exprs which we previously weren't doing and would cause ICEs in `adt_const_params` + `generic_const_exprs` from attempting to prove the wf goals when the length was an unevaluated constant with `'erased` in the `ty` field of `Const`

The duplicate errors are caused by the fact that `const_arg_to_const`/`array_len_to_const` in `FnCtxt` adds a `WellFormed` goal for the created `Const` which is also checked by the added `WellFormed(array_ty)`. I don't want to change this to just emit a `T: Sized` goal for the element type since that would ignore `ConstArgHasType` wf requirements and generally uncomfortable with the idea of trying to sync up `wf::obligations` for arrays and the code in hir typeck for repeat exprs.

r? ``@compiler-errors``

…errors

Add some triagebot notifications for nnethercote.

r? ```@compiler-errors```