rustdoc: heavily simplify the synthesis of auto trait impls
`gd --numstat HEAD~2 HEAD src/librustdoc/clean/auto_trait.rs`
**+315 -705** 🟩🟥🟥🟥⬛
---
As outlined in issue #113015, there are currently 3[^1] large separate routines that “clean” `rustc_middle::ty` data types related to generics & predicates to rustdoc data types. Every single one has their own kinds of bugs. While I've patched a lot of bugs in each of the routines in the past, it's about time to unify them. This PR is only the first in a series. It completely **yanks** the custom “bounds cleaning” of mod `auto_trait` and reuses the routines found in mod `simplify`. As alluded to, `simplify` is also flawed but it's still more complete than `auto_trait`'s routines. [See also my review comment over at `tests/rustdoc/synthetic_auto/bounds.rs`](https://github.com/rust-lang/rust/pull/123340#discussion_r1546900539).
This is preparatory work for rewriting “bounds cleaning” from scratch in follow-up PRs in order to finally [fix] #113015.
Apart from that, I've eliminated all potential sources of *instability* in the rendered output.
See also #119597. I'm pretty sure this fixes#119597.
This PR does not attempt to fix [any other issues related to synthetic auto trait impls](https://github.com/rust-lang/rust/issues?q=is%3Aissue+is%3Aopen+label%3AA-synthetic-impls%20label%3AA-auto-traits).
However, it's definitely meant to be a *stepping stone* by making `auto_trait` more contributor-friendly.
---
* Replace `FxHash{Map,Set}` with `FxIndex{Map,Set}` to guarantee a stable iteration order
* Or as a perf opt, `UnordSet` (a thin wrapper around `FxHashSet`) in cases where we never iterate over the set.
* Yes, we do make use of `swap_remove` but that shouldn't matter since all the callers are deterministic. It does make the output less “predictable” but it's still better than before. Ofc, I rely on `rustc_infer` being deterministic. I hope that holds.
* Utilizing `clean::simplify` over the custom “bounds cleaning” routines wipes out the last reference to `collect_referenced_late_bound_regions` in rustdoc (`simplify` uses `bound_vars`) which was a source of instability / unpredictability (cc #116388)
* Remove the types `RegionTarget` and `RegionDeps` from `librustdoc`. They were duplicates of the identical types found in `rustc`. Just import them from `rustc`. For some reason, they were duplicated when splitting `auto_trait` in two in #49711.
* Get rid of the useless “type namespace” `AutoTraitFinder` in `librustdoc`
* The struct only held a `DocContext`, it was over-engineered
* Turn the associated functions into free ones
* Eliminates rightward drift; increases legibility
* `rustc` also contains a useless `AutoTraitFinder` struct but I plan on removing that in a follow-up PR
* Rename a bunch of methods to be way more descriptive
* Eliminate `use super::*;`
* Lead to `clean/mod.rs` accumulating a lot of unnecessary imports
* Made `auto_traits` less modular
* Eliminate a custom `TypeFolder`: We can just use the rustc helper `fold_regions` which does that for us
I plan on adding extensive documentation to `librustdoc`'s `auto_trait` in follow-up PRs.
I don't want to do that in this PR because further refactoring & bug fix PRs may alter the overall structure of `librustdoc`'s & `rustc`'s `auto_trait` modules to a great degree. I'm slowly digging into the dark details of `rustc`'s `auto_trait` module again and once I have the full picture I will be able to provide proper docs.
---
While this PR does indeed touch `rustc`'s `auto_trait` — mostly tiny refactorings — I argue this PR doesn't need any compiler reviewers next to rustdoc ones since that module falls under the purview of rustdoc — it used to be part of `librustdoc` after all (#49711).
Sorry for not having split this into more commits. If you'd like me to I can try to split it into more atomic commits retroactively. However, I don't know if that would actually make reviewing easier. I think the best way to review this might just be to place the master version of `auto_trait` on the left of your screen and the patched one on the right, not joking.
r? `@GuillaumeGomez`
[^1]: Or even 4 depending on the way you're counting.
Note impact of `-Cstrip` on backtraces
It is not always clear to people what the impact of `-Cstrip` options are. They are a common question on sites like StackOverflow, and sometimes people even report bugs with "no backtrace" after deliberately mangling the symbol table. We cannot exhaustively document every permutation, but we should warn people about common effects.
It is not always clear to people what the impact of `-Cstrip` options are.
They are a common question on sites like StackOverflow, and sometimes
people even report bugs with "no backtrace" after deliberately mangling
the symbol table. We cannot exhaustively document every permutation, but
we should warn people about common effects.
Refactor the way bootstrap invokes `cargo miri`
Instead of basically doing `cargo run --manifest-path=<cargo-miri's manifest> -- miri`, let's invoke the `cargo-miri` binary directly. That means less indirections, and also makes it easier to e.g. run the libcore test suite in Miri. (But there are still other issues with that.)
Also also adjusted Miri's stage numbering so that it is consistent with rustc/rustdoc.
This also makes `./x.py test miri` honor `--no-doc`.
And this fixes https://github.com/rust-lang/rust/issues/123177 by moving where we handle parallel_compiler.
Rewrite `core-no-fp-fmt-parse` test in Rust
Claiming the simple "core-no-fp-fmt-parse" test from #121876. `run_make_support` was altered with `arg_path` written in #121918 by `@abhay-51,` with additional doc comment.
Preliminary GSoC contribution for the project proposal mentored by `@jieyouxu.`
Make source tarball generation more reproducible
This PR performs several changes to source tarball generation (`x dist rustc-src`) in order to make it more reproducible (in light of the recent "xz backdoor"...). I want to follow up on it with making a separate CI workflow for generating the tarball.
After this PR, running this locally produces identical checksums:
```bash
$ ./x dist rustc-src
$ sha256sum build/dist/rustc-1.79.0-src.tar.gz
$ ./x dist rustc-src
$ sha256sum build/dist/rustc-1.79.0-src.tar.gz
```
r? `@Mark-Simulacrum`
make some doc comments not doc tests
`./miri test --doc` will run doctests even if we have them disabled (that's a cargo quirk: https://github.com/rust-lang/cargo/issues/13668). This fixes that command to not fail.
compiletest: print reason for failing to read tests
Turns this
```
Could not read tests from /path/to/rust/tests/run-make
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Build completed unsuccessfully in 0:00:05
```
into this:
```
Could not read tests from /path/to/rust/tests/run-make: run-make tests cannot have both `Makefile` and `rmake.rs`
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Build completed unsuccessfully in 0:00:05
```
While first one is technically correct - it's not helpful at all, adding backtrace is not making it any better.
