Commit Graph

2250 Commits

Author SHA1 Message Date
Matthias Krüger
1889e5a00b
Rollup merge of #118694 - celinval:smir-alloc-methods, r=ouz-a
Add instance evaluation and methods to read an allocation in StableMIR

The instance evaluation is needed to handle intrinsics such as `type_id` and `type_name`.

Since we now use Allocation to represent all evaluated constants, provide a few methods to help process the data inside an allocation.

I've also started to add a structured way to get information about the compilation target machine. For now, I've only added information needed to process an allocation.

r? ``````@ouz-a``````
2023-12-08 23:15:12 +01:00
Michael Goulet
cb41509601 Uplift canonicalizer into new trait solver crate 2023-12-08 17:44:01 +00:00
Celina G. Val
4c9e842a09 Add instance evaluation and methods to read alloc
The instance evaluation is needed to handle intrinsics such as
`type_id` and `type_name`.

Since we now use Allocation to represent all evaluated constants,
provide a few methods to help process the data inside an allocation.
2023-12-07 17:01:29 -08:00
Zalathar
47e6e5ee67 coverage: Avoid unnecessary macros in unit tests
These macros don't provide enough value to justify their complexity, when they
can just as easily be functions instead.
2023-12-07 11:12:48 +11:00
bors
84a554cda9 Auto merge of #117072 - betrusted-io:unwinding-crate-support, r=cuviper
Use `unwinding` crate for unwinding on Xous platform

This patch adds support for using [unwinding](https://github.com/nbdd0121/unwinding) on platforms where libunwinding isn't viable. An example of such a platform is `riscv32imac-unknown-xous-elf`.

### Background

The Rust project maintains a fork of llvm at [llvm-project](https://github.com/rust-lang/llvm-project/) where it applies patches on top of the llvm project. This mostly seems to be to get unwinding support for the SGX project, and there may be other patches that I'm unaware of.

There is a lot of machinery in the build system to support compiling `libunwind` on other platforms, and I needed to add additional patches to llvm in order to add support for Xous.

Rather than continuing down this path, it seemed much easier to use a Rust-based library. The `unwinding` crate by `@nbdd0121` fits this description perfectly.

### Future work

This could potentially replace the custom patches for `libunwind` on other platforms such as SGX, and could enable unwinding support on many more exotic platforms.

### Anti-goals

This is not designed to replace `libunwind` on tier-one platforms or those where unwinding support already exists. There is already a well-established approach for unwinding there. Instead, this aims to enable unwinding on new platforms where C++ code may be difficult to compile.
2023-12-06 02:23:01 +00:00
bors
db07cccb1e Auto merge of #113730 - belovdv:jobserver-init-check, r=petrochenkov
Report errors in jobserver inherited through environment variables

This pr attempts to catch situations, when jobserver exists, but is not being inherited.

r? `@petrochenkov`
2023-12-03 16:28:22 +00:00
Ralf Jung
71c9ceb4da update hashbrown 2023-12-02 19:16:09 +01:00
Eric Huss
b07e3160a0 Update mdbook to 0.4.36 2023-11-29 15:52:16 -08:00
belovdv
45e6342346 jobserver: check file descriptors 2023-11-29 18:00:03 +03:00
bors
3dbb4da042 Auto merge of #117301 - saethlin:finish-rmeta-encoding, r=WaffleLapkin
Call FileEncoder::finish in rmeta encoding

Fixes https://github.com/rust-lang/rust/issues/117254

The bug here was that rmeta encoding never called FileEncoder::finish. Now it does. Most of the changes here are needed to support that, since rmeta encoding wants to finish _then_ access the File in the encoder, so finish can't move out.

I tried adding a `cfg(debug_assertions)` exploding Drop impl to FileEncoder that checked for finish being called before dropping, but fatal errors cause unwinding so this isn't really possible. If we encounter a fatal error with a dirty FileEncoder, the Drop impl ICEs even though the implementation is correct. If we try to paper over that by wrapping FileEncoder in ManuallyDrop then that just erases the fact that Drop automatically checks that we call finish on all paths.

I also changed the name of DepGraph::encode to DepGraph::finish_encoding, because that's what it does and it makes the fact that it is the path to FileEncoder::finish less confusing.

r? `@WaffleLapkin`
2023-11-26 14:43:02 +00:00
Nicholas Nethercote
af3fbb3607 Remove unnecessary dependencies. 2023-11-26 08:38:42 +11:00
Nicholas Nethercote
df9f83987a Remove rustc_error_messages/messages.ftl.
It's empty, and it doesn't even make sense, because
`rustc_error_messages` is a lower-level crate than `rustc_errors`.
2023-11-26 08:37:27 +11:00
bors
0f696e555f Auto merge of #118229 - crlf0710:final_bump_unicode15, r=Mark-Simulacrum
Bump `unicase` crate version.

This bumps `unicase` crate to align with Unicode 15.

Closes #101840.
2023-11-24 19:41:10 +00:00
Matthias Krüger
7e3ec1b0e2
Rollup merge of #117656 - ChrisDenton:invalid, r=thomcc
Update windows-bindgen and define `INVALID_HANDLE_VALUE` ourselves

We generate bindings to the Windows API via the `windows-bindgen` crate, which is ultimately what's also used to generate the `windows-sys` and `windows` crates. However, there currently is some custom sauce just for std which makes it a bit different from the vanilla bindings. I would love for us to reduce and eventually remove the differences entirely so that std is using the exact same bindings as everyone else. Maybe in the future we can even just have a normal dependency on `windows-sys`.

This PR removes one of those special things. Our definition of `INVALID_HANDLE_VALUE` relies on an experimental nightly feature for strict provenance, so lets bring that back in house. It also excludes it from the codegen step though that isn't strictly necessary as we override it in any case.

This PR also updates windows-bingen to 0.52.0.
2023-11-24 08:23:52 +01:00
Charles Lew
806b2b2553 Bump unicase crate version. 2023-11-23 18:55:36 +08:00
Ben Kimock
fbaa24ee35 Call FileEncoder::finish in rmeta encoding 2023-11-22 22:49:22 -05:00
Nicholas Nethercote
3ef9d4d0ed Replace custom_encodable with encodable.
By default, `newtype_index!` types get a default `Encodable`/`Decodable`
impl. You can opt out of this with `custom_encodable`. Opting out is the
opposite to how Rust normally works with autogenerated (derived) impls.

This commit inverts the behaviour, replacing `custom_encodable` with
`encodable` which opts into the default `Encodable`/`Decodable` impl.
Only 23 of the 59 `newtype_index!` occurrences need `encodable`.

Even better, there were eight crates with a dependency on
`rustc_serialize` just from unused default `Encodable`/`Decodable`
impls. This commit removes that dependency from those eight crates.
2023-11-22 18:37:14 +11:00
Nicholas Nethercote
ce363bb6e6 Remove IterDelimited.
itertools has `with_position` which does the same thing.
2023-11-22 08:13:21 +11:00
Nicholas Nethercote
3eadc6844b Update itertools to 0.11.
Because the API for `with_position` improved in 0.11 and I want to use
it.
2023-11-22 08:13:21 +11:00
bors
19079cf804 Auto merge of #115526 - arttet:master, r=jackh726
Add arm64e-apple-ios & arm64e-apple-darwin targets

This introduces

*  `arm64e-apple-ios`
*  `arm64e-apple-darwin`

Rust targets for support `arm64e` architecture on `iOS` and `Darwin`.

So, this is a first approach for integrating to the Rust compiler.

## Tier 3 Target Policy

> * A tier 3 target must have a designated developer or developers (the "target
maintainers") on record to be CCed when issues arise regarding the target.
(The mechanism to track and CC such developers may evolve over time.)

I will be the target maintainer.

> * Targets must use naming consistent with any existing targets; for instance, a
target for the same CPU or OS as an existing Rust target should use the same
name for that CPU or OS. Targets should normally use the same names and
naming conventions as used elsewhere in the broader ecosystem beyond Rust
(such as in other toolchains), unless they have a very good reason to
diverge. Changing the name of a target can be highly disruptive, especially
once the target reaches a higher tier, so getting the name right is important
even for a tier 3 target.
Target names should not introduce undue confusion or ambiguity unless
absolutely necessary to maintain ecosystem compatibility. For example, if
the name of the target makes people extremely likely to form incorrect
beliefs about what it targets, the name should be changed or augmented to
disambiguate it.
If possible, use only letters, numbers, dashes and underscores for the name.
Periods (.) are known to cause issues in Cargo.

The target names `arm64e-apple-ios`, `arm64e-apple-darwin` were derived from `aarch64-apple-ios`, `aarch64-apple-darwin`.
In this [ticket,](#73628) people discussed the best suitable names for these targets.

> In some cases, the arm64e arch might be "different". For example:
> * `thread_set_state` might fail with (os/kern) protection failure if we try to call it from arm64 process to arm64e process.
> * The returning value of dlsym is PAC signed on arm64e, while left untouched on arm64
> * Some function like pthread_create_from_mach_thread requires a PAC signed function pointer on arm64e, which is not required on arm64.

So, I have chosen them because there are similar triplets in LLVM. I think there are no more suitable names for these targets.

> * Tier 3 targets may have unusual requirements to build or use, but must not
create legal issues or impose onerous legal terms for the Rust project or for
Rust developers or users.
The target must not introduce license incompatibilities.
Anything added to the Rust repository must be under the standard Rust
license (MIT OR Apache-2.0).
The target must not cause the Rust tools or libraries built for any other
host (even when supporting cross-compilation to the target) to depend
on any new dependency less permissive than the Rust licensing policy. This
applies whether the dependency is a Rust crate that would require adding
new license exceptions (as specified by the tidy tool in the
rust-lang/rust repository), or whether the dependency is a native library
or binary. In other words, the introduction of the target must not cause a
user installing or running a version of Rust or the Rust tools to be
subject to any new license requirements.
Compiling, linking, and emitting functional binaries, libraries, or other
code for the target (whether hosted on the target itself or cross-compiling
from another target) must not depend on proprietary (non-FOSS) libraries.
Host tools built for the target itself may depend on the ordinary runtime
libraries supplied by the platform and commonly used by other applications
built for the target, but those libraries must not be required for code
generation for the target; cross-compilation to the target must not require
such libraries at all. For instance, rustc built for the target may
depend on a common proprietary C runtime library or console output library,
but must not depend on a proprietary code generation library or code
optimization library. Rust's license permits such combinations, but the
Rust project has no interest in maintaining such combinations within the
scope of Rust itself, even at tier 3.
"onerous" here is an intentionally subjective term. At a minimum, "onerous"
legal/licensing terms include but are not limited to: non-disclosure
requirements, non-compete requirements, contributor license agreements
(CLAs) or equivalent, "non-commercial"/"research-only"/etc terms,
requirements conditional on the employer or employment of any particular
Rust developers, revocable terms, any requirements that create liability
for the Rust project or its developers or users, or any requirements that
adversely affect the livelihood or prospects of the Rust project or its
developers or users.

No dependencies were added to Rust.

> * Neither this policy nor any decisions made regarding targets shall create any
binding agreement or estoppel by any party. If any member of an approving
Rust team serves as one of the maintainers of a target, or has any legal or
employment requirement (explicit or implicit) that might affect their
decisions regarding a target, they must recuse themselves from any approval
decisions regarding the target's tier status, though they may otherwise
participate in discussions.
>    * This requirement does not prevent part or all of this policy from being
cited in an explicit contract or work agreement (e.g. to implement or
maintain support for a target). This requirement exists to ensure that a
developer or team responsible for reviewing and approving a target does not
face any legal threats or obligations that would prevent them from freely
exercising their judgment in such approval, even if such judgment involves
subjective matters or goes beyond the letter of these requirements.

Understood.
I am not a member of a Rust team.

> * Tier 3 targets should attempt to implement as much of the standard libraries
as possible and appropriate (core for most targets, alloc for targets
that can support dynamic memory allocation, std for targets with an
operating system or equivalent layer of system-provided functionality), but
may leave some code unimplemented (either unavailable or stubbed out as
appropriate), whether because the target makes it impossible to implement or
challenging to implement. The authors of pull requests are not obligated to
avoid calling any portions of the standard library on the basis of a tier 3
target not implementing those portions.

Understood.
`std` is supported.

> * The target must provide documentation for the Rust community explaining how
to build for the target, using cross-compilation if possible. If the target
supports running binaries, or running tests (even if they do not pass), the
documentation must explain how to run such binaries or tests for the target,
using emulation if possible or dedicated hardware if necessary.

Building is described in the derived target doc.

> * Tier 3 targets must not impose burden on the authors of pull requests, or
other developers in the community, to maintain the target. In particular,
do not post comments (automated or manual) on a PR that derail or suggest a
block on the PR based on a tier 3 target. Do not send automated messages or
notifications (via any medium, including via `@)` to a PR author or others
involved with a PR regarding a tier 3 target, unless they have opted into
such messages.
>    * Backlinks such as those generated by the issue/PR tracker when linking to
an issue or PR are not considered a violation of this policy, within
reason. However, such messages (even on a separate repository) must not
generate notifications to anyone involved with a PR who has not requested
such notifications.

Understood.

> * Patches adding or updating tier 3 targets must not break any existing tier 2
or tier 1 target, and must not knowingly break another tier 3 target without
approval of either the compiler team or the maintainers of the other tier 3
target.
>     * In particular, this may come up when working on closely related targets,
such as variations of the same architecture with different features. Avoid
introducing unconditional uses of features that another variation of the
target may not have; use conditional compilation or runtime detection, as
appropriate, to let each target run code supported by that target.

These targets are not fully ABI compatible with arm64e code.

#73628
2023-11-20 03:11:17 +00:00
bors
4f3da903a4 Auto merge of #116828 - compiler-errors:nightlyify-rustc_type_ir, r=jackh726
Begin to abstract `rustc_type_ir` for rust-analyzer

This adds the "nightly" feature which is used by the compiler, and falls back to more simple implementations when that is not active.

r? `@lcnr` or `@jackh726`
2023-11-19 22:55:15 +00:00
klensy
c653bb9a6b jsondocck: bump jsonpath to 0.3, dropping few dup dependencies
changes: https://github.com/freestrings/jsonpath/compare/v0.2.6...v0.3.0

self_cell: bump to 0.10.3 due to RUSTSEC-2023-0070

https://rustsec.org/advisories/RUSTSEC-2023-0070.html
https://github.com/Voultapher/self_cell/issues/49

bump h2 to 0.3.22, dropping few dup crate versions

https://github.com/hyperium/h2/blob/v0.3.22/CHANGELOG.md
2023-11-18 12:56:54 +03:00
Michael Goulet
4506681e2f Begin nightly-ifying rustc_type_ir 2023-11-18 00:20:00 +00:00
Chris Denton
00a12af3ca
Update windows-bindgen 2023-11-17 12:18:04 +00:00
Oğuz Ağcayazı
ebd9c145f6 better formatting for statements 2023-11-17 13:28:07 +03:00
Philipp Krones
2ac2b26aec
Update Cargo.lock 2023-11-16 19:20:09 +01:00
Sean Cross
2a533df5bd Cargo.lock: add unwinding to lock file
Add `unwinding` as a dependency. This is required on platforms where
unwinding isn't provided by llvm.

Signed-off-by: Sean Cross <sean@xobs.io>
2023-11-16 15:23:09 +08:00
Artyom Tetyukhin
f5e3492194
Add arm64e-apple-ios target 2023-11-15 14:55:18 +04:00
klensy
7142c8d83c bump few ICU4X leftover deps
implements https://github.com/rust-lang/rust/pull/117632#issuecomment-1795027801 suggestion
2023-11-09 14:53:21 +03:00
bors
287ae4db75 Auto merge of #117632 - Nilstrieb:icup, r=davidtwco
Update ICU4X

This updates all ICU4X crates and regenerates rustc_baked_icu_data.

Since the new unicode license under which they are licensed does not have an SPDX identifier yet, we define some exceptions. The license has to be reviewed to make sure it is still fine to use here, but I assume that is the case.

I also added an exception for rustc_icu_data to the unexplained ignore doctest tidy lint. This is a bit hacky but the whole style.rs in tidy is a mess so I didn't want to touch it more than this small hack.

part of #112865

r? `@davidtwco` `@wesleywiser` `@Manishearth`
2023-11-09 09:00:57 +00:00
Matthias Krüger
adf4981969
Rollup merge of #117663 - klensy:bump-deps, r=davidtwco
bump some deps

* drop `num_cpus` from rust-installer as not used
* update `rayon`, `rayon-core`, which drops it's deps on `num_cpus` and `crossbeam-channel` (for bootstrap too) (https://github.com/rayon-rs/rayon/blob/v1.8.0/RELEASES.md)
* update `errno`, which drops `errno-dragonfly` (5341791935/CHANGELOG.md)
2023-11-08 11:25:55 +01:00
bors
118a2deea5 Auto merge of #117617 - Urgau:bump-libc-0.2.150, r=Mark-Simulacrum
Bump libc dependency

This bumps the `libc` crate to version 0.2.150 which includes https://github.com/rust-lang/libc/pull/3410 which will help remove the old and deprecated check-cfg syntax.

Extracted from https://github.com/rust-lang/rust/pull/117612
2023-11-07 17:18:36 +00:00
klensy
eed89185bb bump some deps
drop num_cpus from rust-installer as not used
update rayon, rayon-core, which drops it's deps on num_cpus and crossbeam-channel (for bootstrap too) (https://github.com/rayon-rs/rayon/blob/v1.8.0/RELEASES.md)
update erro, which drops errno-dragonfly (5341791935/CHANGELOG.md)
2023-11-07 15:33:59 +03:00
Nilstrieb
ffffc2038f Update ICU4X
This updates all ICU4X crates and regenerates rustc_baked_icu_data.

Since the new unicode license under which they are licensed does not
have an SPDX identifier yet, we define some exceptions. The license has
to be reviewed to make sure it is still fine to use here, but I assume
that is the case.

I also added an exception for rustc_icu_data to the unexplained ignore
doctest tidy lint. This is a bit hacky but the whole style.rs in tidy is
a mess so I didn't want to touch it more than this small hack.
2023-11-06 13:42:20 +00:00
bors
f9b644636f Auto merge of #117435 - SparrowLii:nightly_parallel, r=oli-obk,davidtwco
enable parallel rustc front end in nightly builds

Refers to the [MCP](https://github.com/rust-lang/compiler-team/issues/681), this pr does:
1. Enable the parallel front end in nightly builds, and keep the default number of threads as 1. Then users can use the parallel rustc front end via -Z threads=n option.

2. Set it up to serial front end for beta/stable builds via bootstrap.

3. Switch over the alt builders from parallel rustc to serial, so we have artifacts without parallel to test against the artifacts with parallel.

r? `@oli-obk`

cc `@cjgillot` `@nnethercote` `@bjorn3` `@Kobzol`
2023-11-06 07:41:22 +00:00
SparrowLii
f2a40e99ff use portable AtomicU64 for powerPC and MIPS 2023-11-06 09:58:51 +08:00
Urgau
15719a8c1d libc: bump dependency to 0.2.150 2023-11-05 18:32:10 +01:00
bors
513a48517e Auto merge of #117504 - pcc:android-link-libunwind, r=Mark-Simulacrum
Remove obsolete support for linking unwinder on Android

Linking libgcc is no longer supported (see #103673), so remove the related link attributes and the check in unwind's build.rs. The check was the last remaining significant piece of logic in build.rs, so remove build.rs as well.
2023-11-05 09:50:21 +00:00
Nicholas Bishop
5d3535c616 Bump compiler_builtins to 0.1.103 2023-11-04 13:11:10 -04:00
Nicholas Nethercote
5c462a32bd Remove support for compiler plugins.
They've been deprecated for four years.

This commit includes the following changes.
- It eliminates the `rustc_plugin_impl` crate.
- It changes the language used for lints in
  `compiler/rustc_driver_impl/src/lib.rs` and
  `compiler/rustc_lint/src/context.rs`. External lints are now called
  "loaded" lints, rather than "plugins" to avoid confusion with the old
  plugins. This only has a tiny effect on the output of `-W help`.
- E0457 and E0498 are no longer used.
- E0463 is narrowed, now only relating to unfound crates, not plugins.
- The `plugin` feature was moved from "active" to "removed".
- It removes the entire plugins chapter from the unstable book.
- It removes quite a few tests, mostly all of those in
  `tests/ui-fulldeps/plugin/`.

Closes #29597.
2023-11-04 08:50:46 +11:00
Peter Collingbourne
654288bbb7 Remove obsolete support for linking unwinder on Android
Linking libgcc is no longer supported (see #103673), so remove the
related link attributes and the check in unwind's build.rs. The check
was the last remaining significant piece of logic in build.rs, so
remove build.rs as well.
2023-11-02 18:06:35 -07:00
Philipp Krones
02562bfdf8
Update Cargo.lock 2023-11-02 17:50:52 +01:00
bors
62270fb4d6 Auto merge of #117204 - nnethercote:rustc_ast_passes, r=compiler-errors
Minor improvements to `rustc_ast_passes`

Some improvements I found while looking at this code.

r? `@compiler-errors`
2023-11-02 10:08:53 +00:00
Matthias Krüger
effc27dea4
Rollup merge of #117488 - GuillaumeGomez:update-minifier, r=notriddle
Update minifier-rs version to 0.3.0

It fixes https://github.com/GuillaumeGomez/minifier-rs/issues/105.

r? ```@notriddle```
2023-11-01 21:40:06 +01:00
Guillaume Gomez
d6666e2ccc Update minifier-rs version to 0.3.0 2023-11-01 15:18:41 +01:00
Michael Goulet
de83057ac4 Use derivative for Clone 2023-10-31 13:16:37 +00:00
Nicholas Nethercote
bb3e09f144 Streamline gate_feature_* macros.
The debug probably isn't useful, and assigning all the `$foo`
metavariables to `foo` variables is verbose and weird. Also, `$x:expr`
usually doesn't have a space after the `:`.
2023-10-31 08:00:53 +11:00
Nicholas Nethercote
28e60de487 Remove memoffset dependency from rustc_query_impl.
The comment explains it's for `unstable_offset_of`, but `offset_of` is
now stable.
2023-10-30 08:25:51 +11:00
Jubilee
48a3865218
Rollup merge of #117268 - nnethercote:rustc_interface, r=oli-obk
`rustc_interface` cleanups

Particularly in and around `--cfg` and `--check-cfg` handling.

r? `@oli-obk`
2023-10-28 01:07:38 -07:00
bors
6f349cdbfa Auto merge of #116471 - notriddle:notriddle/js-trait-alias, r=GuillaumeGomez
rustdoc: use JS to inline target type impl docs into alias

Preview docs:

- https://notriddle.com/rustdoc-html-demo-5/js-trait-alias/std/io/type.Result.html

- https://notriddle.com/rustdoc-html-demo-5/js-trait-alias-compiler/rustc_middle/ty/type.PolyTraitRef.html

This pull request also includes a bug fix for trait alias inlining across crates. This means more documentation is generated, and is why ripgrep runs slower (it's a thin wrapper on top of the `grep` crate, so 5% of its docs are now the Result type).

- Before, built with rustdoc 1.75.0-nightly (aa1a71e9e 2023-10-26), Result type alias method docs are missing: http://notriddle.com/rustdoc-html-demo-5/ripgrep-js-nightly/rg/type.Result.html
- After, built with this branch, all the methods on Result are shown: http://notriddle.com/rustdoc-html-demo-5/ripgrep-js-trait-alias/rg/type.Result.html

*Review note: This is mostly just reverting https://github.com/rust-lang/rust/pull/115201. The last commit has the new work in it.*

Fixes #115718

This is an attempt to balance three problems, each of which would
be violated by a simpler implementation:

- A type alias should show all the `impl` blocks for the target
  type, and vice versa, if they're applicable. If nothing was
  done, and rustdoc continues to match them up in HIR, this
  would not work.

- Copying the target type's docs into its aliases' HTML pages
  directly causes far too much redundant HTML text to be generated
  when a crate has large numbers of methods and large numbers
  of type aliases.

- Using JavaScript exclusively for type alias impl docs would
  be a functional regression, and could make some docs very hard
  to find for non-JS readers.

- Making sure that only applicable docs are show in the
  resulting page requires a type checkers. Do not reimplement
  the type checker in JavaScript.

So, to make it work, rustdoc stashes these type-alias-inlined docs
in a JSONP "database-lite". The file is generated in `write_shared.rs`,
included in a `<script>` tag added in `print_item.rs`, and `main.js`
takes care of patching the additional docs into the DOM.

The format of `trait.impl` and `type.impl` JS files are superficially
similar. Each line, except the JSONP wrapper itself, belongs to a crate,
and they are otherwise separate (rustdoc should be idempotent). The
"meat" of the file is HTML strings, so the frontend code is very simple.
Links are relative to the doc root, though, so the frontend needs to fix
that up, and inlined docs can reuse these files.

However, there are a few differences, caused by the sophisticated
features that type aliases have. Consider this crate graph:

```text
 ---------------------------------
 | crate A: struct Foo<T>        |
 |          type Bar = Foo<i32>  |
 |          impl X for Foo<i8>   |
 |          impl Y for Foo<i32>  |
 ---------------------------------
     |
 ----------------------------------
 | crate B: type Baz = A::Foo<i8> |
 |          type Xyy = A::Foo<i8> |
 |          impl Z for Xyy        |
 ----------------------------------
```

The type.impl/A/struct.Foo.js JS file has a structure kinda like this:

```js
JSONP({
"A": [["impl Y for Foo<i32>", "Y", "A::Bar"]],
"B": [["impl X for Foo<i8>", "X", "B::Baz", "B::Xyy"], ["impl Z for Xyy", "Z", "B::Baz"]],
});
```

When the type.impl file is loaded, only the current crate's docs are
actually used. The main reason to bundle them together is that there's
enough duplication in them for DEFLATE to remove the redundancy.

The contents of a crate are a list of impl blocks, themselves
represented as lists. The first item in the sublist is the HTML block,
the second item is the name of the trait (which goes in the sidebar),
and all others are the names of type aliases that successfully match.

This way:

- There's no need to generate these files for types that have no aliases
  in the current crate. If a dependent crate makes a type alias, it'll
  take care of generating its own docs.
- There's no need to reimplement parts of the type checker in
  JavaScript. The Rust backend does the checking, and includes its
  results in the file.
- Docs defined directly on the type alias are dropped directly in the
  HTML by `render_assoc_items`, and are accessible without JavaScript.
  The JSONP file will not list impl items that are known to be part
  of the main HTML file already.

[JSONP]: https://en.wikipedia.org/wiki/JSONP
2023-10-27 23:08:24 +00:00