rust/compiler
bors 5dbaafdb93 Auto merge of #123340 - fmease:rustdoc-simplify-auto-trait-impl-synth, r=GuillaumeGomez
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.
2024-04-02 12:13:44 +00:00
..
rustc
rustc_abi Use the Align type when parsing alignment attributes 2024-04-01 03:05:55 +01:00
rustc_arena rename ptr::invalid -> ptr::without_provenance 2024-02-21 20:15:52 +01:00
rustc_ast Implement mut ref/mut ref mut 2024-03-27 09:53:23 -04:00
rustc_ast_ir Fix typo in VisitorResult 2024-03-08 23:20:29 -05:00
rustc_ast_lowering Implement mut ref/mut ref mut 2024-03-27 09:53:23 -04:00
rustc_ast_passes Rollup merge of #123188 - klensy:clippy-me2, r=Nilstrieb 2024-03-29 15:17:11 +01:00
rustc_ast_pretty Auto merge of #123080 - Jules-Bertholet:mut-ref-mut, r=Nadrieril 2024-03-29 11:08:11 +00:00
rustc_attr Use the Align type when parsing alignment attributes 2024-04-01 03:05:55 +01:00
rustc_baked_icu_data
rustc_borrowck Stop calling visitors V 2024-03-30 11:13:33 -04:00
rustc_builtin_macros Fix error message for env! when env var is not valid Unicode 2024-04-01 05:44:45 +01:00
rustc_codegen_cranelift Auto merge of #122450 - Urgau:simplify-trim-paths-feature, r=michaelwoerister 2024-03-29 14:00:21 +00:00
rustc_codegen_gcc stabilize ptr.is_aligned, move ptr.is_aligned_to to a new feature gate 2024-03-29 19:59:46 -04:00
rustc_codegen_llvm Auto merge of #122972 - beetrees:use-align-type, r=fee1-dead 2024-04-01 03:16:45 +00:00
rustc_codegen_ssa Rollup merge of #123188 - klensy:clippy-me2, r=Nilstrieb 2024-03-29 15:17:11 +01:00
rustc_const_eval Don't inherit codegen attrs from parent static 2024-03-31 22:34:00 -04:00
rustc_data_structures Auto merge of #121851 - michaelwoerister:mcp-533-effective-vis, r=cjgillot 2024-03-31 16:22:38 +00:00
rustc_driver
rustc_driver_impl Auto merge of #111769 - saethlin:ctfe-backtrace-ctrlc, r=RalfJung 2024-03-26 00:04:03 +00:00
rustc_error_codes Auto merge of #122055 - compiler-errors:stabilize-atb, r=oli-obk 2024-03-19 00:04:09 +00:00
rustc_error_messages Rename SubdiagnosticMessage as SubdiagMessage. 2024-03-05 12:14:49 +11:00
rustc_errors Rollup merge of #122737 - ytmimi:conditionally_ignore_fatal_diagnostic, r=davidtwco 2024-03-24 17:08:15 +01:00
rustc_expand compiler: fix few needless_pass_by_ref_mut clippy lints 2024-03-28 11:37:52 +03:00
rustc_feature Auto merge of #123080 - Jules-Bertholet:mut-ref-mut, r=Nadrieril 2024-03-29 11:08:11 +00:00
rustc_fluent_macro Rename SubdiagnosticMessage as SubdiagMessage. 2024-03-05 12:14:49 +11:00
rustc_fs_util
rustc_graphviz
rustc_hir Auto merge of #123080 - Jules-Bertholet:mut-ref-mut, r=Nadrieril 2024-03-29 11:08:11 +00:00
rustc_hir_analysis Auto merge of #122972 - beetrees:use-align-type, r=fee1-dead 2024-04-01 03:16:45 +00:00
rustc_hir_pretty Implement mut ref/mut ref mut 2024-03-27 09:53:23 -04:00
rustc_hir_typeck Fixup parsing of rustc_never_type_options attribute 2024-04-01 10:56:33 +00:00
rustc_incremental Auto merge of #122721 - oli-obk:merge_queries, r=davidtwco 2024-03-25 01:33:46 +00:00
rustc_index doc: Add better explanation 2024-03-06 16:54:42 +01:00
rustc_index_macros Remove SpecOptionPartialEq 2024-03-19 16:32:01 +00:00
rustc_infer Rollup merge of #123188 - klensy:clippy-me2, r=Nilstrieb 2024-03-29 15:17:11 +01:00
rustc_interface Auto merge of #115220 - Zoxc:revive-gcx-ptr, r=oli-obk 2024-03-28 14:00:08 +00:00
rustc_lexer Silence redundant error on char literal that was meant to be a string in 2021 edition 2024-03-17 23:35:19 +00:00
rustc_lint Add support for NonNull in ambiguous_wide_ptr_comparisions 2024-03-29 22:02:07 +01:00
rustc_lint_defs Rollup merge of #121720 - tmandry:split-refining, r=compiler-errors 2024-03-16 23:28:47 +01:00
rustc_llvm RustWrapper: update call for llvm/llvm-project@44d037cc25 2024-03-26 14:10:25 -04:00
rustc_log bump tracing-tree to 0.3 2024-03-30 17:39:43 +03:00
rustc_macros Rename diagnostic derive things. 2024-03-11 10:06:34 +11:00
rustc_metadata Replace RemapFileNameExt::for_codegen with explicit calls 2024-03-28 18:47:26 +01:00
rustc_middle Auto merge of #123327 - BoxyUwU:param_env_docs_rewrite, r=compiler-errors 2024-04-01 23:02:17 +00:00
rustc_mir_build Auto merge of #122046 - Nadrieril:integrate-or-pats2, r=matthewjasper 2024-04-01 12:31:27 +00:00
rustc_mir_dataflow refactor check_{lang,library}_ub: use a single intrinsic, put policy into library 2024-03-23 18:45:05 +01:00
rustc_mir_transform Auto merge of #123194 - matthiaskrgr:rollup-vhdc8hw, r=matthiaskrgr 2024-03-29 16:02:04 +00:00
rustc_monomorphize Only allow upstream calls to LLVM intrinsics, not any link_name function 2024-04-01 20:31:19 -04:00
rustc_next_trait_solver Require foldability part of interner item bounds, remove redundant where clauses 2024-03-28 12:30:52 -04:00
rustc_parse Auto merge of #123080 - Jules-Bertholet:mut-ref-mut, r=Nadrieril 2024-03-29 11:08:11 +00:00
rustc_parse_format Extend format arg help for simple tuple index access expression 2024-03-16 22:33:02 +00:00
rustc_passes Auto merge of #122450 - Urgau:simplify-trim-paths-feature, r=michaelwoerister 2024-03-29 14:00:21 +00:00
rustc_pattern_analysis Rollup merge of #123242 - Nadrieril:require-contiguous-enum-indices, r=compiler-errors 2024-03-31 11:50:41 +02:00
rustc_privacy Rename hir::Local into hir::LetStmt 2024-03-22 20:36:21 +01:00
rustc_query_impl Verify that query keys result in unique dep nodes 2024-03-12 05:31:41 +01:00
rustc_query_system Remove CacheSelector trait now that we can use GATs 2024-03-26 11:03:23 +00:00
rustc_resolve remove def_id_to_node_id in ast lowering 2024-03-28 16:58:03 +08:00
rustc_serialize Stabilize associated type bounds 2024-03-08 20:56:25 +00:00
rustc_session Rollup merge of #123200 - maurer:kcfi-abort, r=compiler-errors 2024-03-30 14:30:50 +01:00
rustc_smir Normalize the result of Fields::ty_with_args 2024-03-28 13:22:10 -07:00
rustc_span Auto merge of #121268 - Urgau:improve_ambi_wide_ptr_cmps, r=Nadrieril 2024-03-29 18:23:57 +00:00
rustc_symbol_mangling CFI: Rewrite closure and coroutine instances to their trait method 2024-03-30 16:40:38 +00:00
rustc_target CFI: Enable KCFI testing of run-pass tests 2024-03-26 03:16:41 +00:00
rustc_trait_selection Auto merge of #123340 - fmease:rustdoc-simplify-auto-trait-impl-synth, r=GuillaumeGomez 2024-04-02 12:13:44 +00:00
rustc_traits Merge check_mod_impl_wf and check_mod_type_wf 2024-03-07 06:27:09 +00:00
rustc_transmute Remove unnecessary Partial/Ord derive 2024-03-27 14:02:15 +00:00
rustc_ty_utils Rollup merge of #123021 - compiler-errors:coroutine-layout-lol, r=oli-obk 2024-03-27 10:13:43 +01:00
rustc_type_ir Require foldability part of interner item bounds, remove redundant where clauses 2024-03-28 12:30:52 -04:00
stable_mir Normalize the result of Fields::ty_with_args 2024-03-28 13:22:10 -07:00