src/librustdoc/core.rs

   1 use rustc_ast::NodeId;
   2 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
   3 use rustc_data_structures::sync::{self, Lrc};
   4 use rustc_errors::emitter::{Emitter, EmitterWriter};
   5 use rustc_errors::json::JsonEmitter;
   6 use rustc_feature::UnstableFeatures;
   7 use rustc_hir::def::{Namespace, Res};
   8 use rustc_hir::def_id::{DefId, DefIdMap, LocalDefId};
   9 use rustc_hir::intravisit::{self, Visitor};
  10 use rustc_hir::{HirId, Path, TraitCandidate};
  11 use rustc_interface::interface;
  12 use rustc_middle::hir::nested_filter;
  13 use rustc_middle::middle::privacy::AccessLevels;
  14 use rustc_middle::ty::{ParamEnv, Ty, TyCtxt};
  15 use rustc_resolve as resolve;
  16 use rustc_session::config::{self, CrateType, ErrorOutputType};
  17 use rustc_session::lint;
  18 use rustc_session::DiagnosticOutput;
  19 use rustc_session::Session;
  20 use rustc_span::symbol::sym;
  21 use rustc_span::{source_map, Span, Symbol};
  22
  23 use std::cell::RefCell;
  24 use std::mem;
  25 use std::rc::Rc;
  26 use std::sync::LazyLock;
  27
  28 use crate::clean::inline::build_external_trait;
  29 use crate::clean::{self, ItemId, TraitWithExtraInfo};
  30 use crate::config::{Options as RustdocOptions, OutputFormat, RenderOptions};
  31 use crate::formats::cache::Cache;
  32 use crate::passes::collect_intra_doc_links::PreprocessedMarkdownLink;
  33 use crate::passes::{self, Condition::*};
  34
  35 pub(crate) use rustc_session::config::{Input, Options, UnstableOptions};
  36
  37 pub(crate) struct ResolverCaches {
  38     pub(crate) markdown_links: Option<FxHashMap<String, Vec<PreprocessedMarkdownLink>>>,
  39     pub(crate) doc_link_resolutions: FxHashMap<(Symbol, Namespace, DefId), Option<Res<NodeId>>>,
  40     /// Traits in scope for a given module.
  41     /// See `collect_intra_doc_links::traits_implemented_by` for more details.
  42     pub(crate) traits_in_scope: DefIdMap<Vec<TraitCandidate>>,
  43     pub(crate) all_traits: Option<Vec<DefId>>,
  44     pub(crate) all_trait_impls: Option<Vec<DefId>>,
  45     pub(crate) all_macro_rules: FxHashMap<Symbol, Res<NodeId>>,
  46 }
  47
  48 pub(crate) struct DocContext<'tcx> {
  49     pub(crate) tcx: TyCtxt<'tcx>,
  50     /// Name resolver. Used for intra-doc links.
  51     ///
  52     /// The `Rc<RefCell<...>>` wrapping is needed because that is what's returned by
  53     /// [`rustc_interface::Queries::expansion()`].
  54     // FIXME: see if we can get rid of this RefCell somehow
  55     pub(crate) resolver: Rc<RefCell<interface::BoxedResolver>>,
  56     pub(crate) resolver_caches: ResolverCaches,
  57     /// Used for normalization.
  58     ///
  59     /// Most of this logic is copied from rustc_lint::late.
  60     pub(crate) param_env: ParamEnv<'tcx>,
  61     /// Later on moved through `clean::Crate` into `cache`
  62     pub(crate) external_traits: Rc<RefCell<FxHashMap<DefId, clean::TraitWithExtraInfo>>>,
  63     /// Used while populating `external_traits` to ensure we don't process the same trait twice at
  64     /// the same time.
  65     pub(crate) active_extern_traits: FxHashSet<DefId>,
  66     // The current set of parameter substitutions,
  67     // for expanding type aliases at the HIR level:
  68     /// Table `DefId` of type, lifetime, or const parameter -> substituted type, lifetime, or const
  69     pub(crate) substs: FxHashMap<DefId, clean::SubstParam>,
  70     /// Table synthetic type parameter for `impl Trait` in argument position -> bounds
  71     pub(crate) impl_trait_bounds: FxHashMap<ImplTraitParam, Vec<clean::GenericBound>>,
  72     /// Auto-trait or blanket impls processed so far, as `(self_ty, trait_def_id)`.
  73     // FIXME(eddyb) make this a `ty::TraitRef<'tcx>` set.
  74     pub(crate) generated_synthetics: FxHashSet<(Ty<'tcx>, DefId)>,
  75     pub(crate) auto_traits: Vec<DefId>,
  76     /// The options given to rustdoc that could be relevant to a pass.
  77     pub(crate) render_options: RenderOptions,
  78     /// This same cache is used throughout rustdoc, including in [`crate::html::render`].
  79     pub(crate) cache: Cache,
  80     /// Used by [`clean::inline`] to tell if an item has already been inlined.
  81     pub(crate) inlined: FxHashSet<ItemId>,
  82     /// Used by `calculate_doc_coverage`.
  83     pub(crate) output_format: OutputFormat,
  84     /// Used by `strip_private`.
  85     pub(crate) show_coverage: bool,
  86 }
  87
  88 impl<'tcx> DocContext<'tcx> {
  89     pub(crate) fn sess(&self) -> &'tcx Session {
  90         self.tcx.sess
  91     }
  92
  93     pub(crate) fn with_param_env<T, F: FnOnce(&mut Self) -> T>(
  94         &mut self,
  95         def_id: DefId,
  96         f: F,
  97     ) -> T {
  98         let old_param_env = mem::replace(&mut self.param_env, self.tcx.param_env(def_id));
  99         let ret = f(self);
 100         self.param_env = old_param_env;
 101         ret
 102     }
 103
 104     pub(crate) fn enter_resolver<F, R>(&self, f: F) -> R
 105     where
 106         F: FnOnce(&mut resolve::Resolver<'_>) -> R,
 107     {
 108         self.resolver.borrow_mut().access(f)
 109     }
 110
 111     /// Call the closure with the given parameters set as
 112     /// the substitutions for a type alias' RHS.
 113     pub(crate) fn enter_alias<F, R>(
 114         &mut self,
 115         substs: FxHashMap<DefId, clean::SubstParam>,
 116         f: F,
 117     ) -> R
 118     where
 119         F: FnOnce(&mut Self) -> R,
 120     {
 121         let old_substs = mem::replace(&mut self.substs, substs);
 122         let r = f(self);
 123         self.substs = old_substs;
 124         r
 125     }
 126
 127     /// Like `hir().local_def_id_to_hir_id()`, but skips calling it on fake DefIds.
 128     /// (This avoids a slice-index-out-of-bounds panic.)
 129     pub(crate) fn as_local_hir_id(tcx: TyCtxt<'_>, item_id: ItemId) -> Option<HirId> {
 130         match item_id {
 131             ItemId::DefId(real_id) => {
 132                 real_id.as_local().map(|def_id| tcx.hir().local_def_id_to_hir_id(def_id))
 133             }
 134             // FIXME: Can this be `Some` for `Auto` or `Blanket`?
 135             _ => None,
 136         }
 137     }
 138
 139     pub(crate) fn with_all_traits(&mut self, f: impl FnOnce(&mut Self, &[DefId])) {
 140         let all_traits = self.resolver_caches.all_traits.take();
 141         f(self, all_traits.as_ref().expect("`all_traits` are already borrowed"));
 142         self.resolver_caches.all_traits = all_traits;
 143     }
 144
 145     pub(crate) fn with_all_trait_impls(&mut self, f: impl FnOnce(&mut Self, &[DefId])) {
 146         let all_trait_impls = self.resolver_caches.all_trait_impls.take();
 147         f(self, all_trait_impls.as_ref().expect("`all_trait_impls` are already borrowed"));
 148         self.resolver_caches.all_trait_impls = all_trait_impls;
 149     }
 150 }
 151
 152 /// Creates a new diagnostic `Handler` that can be used to emit warnings and errors.
 153 ///
 154 /// If the given `error_format` is `ErrorOutputType::Json` and no `SourceMap` is given, a new one
 155 /// will be created for the handler.
 156 pub(crate) fn new_handler(
 157     error_format: ErrorOutputType,
 158     source_map: Option<Lrc<source_map::SourceMap>>,
 159     diagnostic_width: Option<usize>,
 160     unstable_opts: &UnstableOptions,
 161 ) -> rustc_errors::Handler {
 162     let fallback_bundle =
 163         rustc_errors::fallback_fluent_bundle(rustc_errors::DEFAULT_LOCALE_RESOURCES, false);
 164     let emitter: Box<dyn Emitter + sync::Send> = match error_format {
 165         ErrorOutputType::HumanReadable(kind) => {
 166             let (short, color_config) = kind.unzip();
 167             Box::new(
 168                 EmitterWriter::stderr(
 169                     color_config,
 170                     source_map.map(|sm| sm as _),
 171                     None,
 172                     fallback_bundle,
 173                     short,
 174                     unstable_opts.teach,
 175                     diagnostic_width,
 176                     false,
 177                 )
 178                 .ui_testing(unstable_opts.ui_testing),
 179             )
 180         }
 181         ErrorOutputType::Json { pretty, json_rendered } => {
 182             let source_map = source_map.unwrap_or_else(|| {
 183                 Lrc::new(source_map::SourceMap::new(source_map::FilePathMapping::empty()))
 184             });
 185             Box::new(
 186                 JsonEmitter::stderr(
 187                     None,
 188                     source_map,
 189                     None,
 190                     fallback_bundle,
 191                     pretty,
 192                     json_rendered,
 193                     diagnostic_width,
 194                     false,
 195                 )
 196                 .ui_testing(unstable_opts.ui_testing),
 197             )
 198         }
 199     };
 200
 201     rustc_errors::Handler::with_emitter_and_flags(
 202         emitter,
 203         unstable_opts.diagnostic_handler_flags(true),
 204     )
 205 }
 206
 207 /// Parse, resolve, and typecheck the given crate.
 208 pub(crate) fn create_config(
 209     RustdocOptions {
 210         input,
 211         crate_name,
 212         proc_macro_crate,
 213         error_format,
 214         diagnostic_width,
 215         libs,
 216         externs,
 217         mut cfgs,
 218         check_cfgs,
 219         codegen_options,
 220         unstable_opts,
 221         target,
 222         edition,
 223         maybe_sysroot,
 224         lint_opts,
 225         describe_lints,
 226         lint_cap,
 227         scrape_examples_options,
 228         ..
 229     }: RustdocOptions,
 230 ) -> rustc_interface::Config {
 231     // Add the doc cfg into the doc build.
 232     cfgs.push("doc".to_string());
 233
 234     let cpath = Some(input.clone());
 235     let input = Input::File(input);
 236
 237     // By default, rustdoc ignores all lints.
 238     // Specifically unblock lints relevant to documentation or the lint machinery itself.
 239     let mut lints_to_show = vec![
 240         // it's unclear whether these should be part of rustdoc directly (#77364)
 241         rustc_lint::builtin::MISSING_DOCS.name.to_string(),
 242         rustc_lint::builtin::INVALID_DOC_ATTRIBUTES.name.to_string(),
 243         // these are definitely not part of rustdoc, but we want to warn on them anyway.
 244         rustc_lint::builtin::RENAMED_AND_REMOVED_LINTS.name.to_string(),
 245         rustc_lint::builtin::UNKNOWN_LINTS.name.to_string(),
 246         rustc_lint::builtin::UNEXPECTED_CFGS.name.to_string(),
 247         // this lint is needed to support `#[expect]` attributes
 248         rustc_lint::builtin::UNFULFILLED_LINT_EXPECTATIONS.name.to_string(),
 249     ];
 250     lints_to_show.extend(crate::lint::RUSTDOC_LINTS.iter().map(|lint| lint.name.to_string()));
 251
 252     let (lint_opts, lint_caps) = crate::lint::init_lints(lints_to_show, lint_opts, |lint| {
 253         Some((lint.name_lower(), lint::Allow))
 254     });
 255
 256     let crate_types =
 257         if proc_macro_crate { vec![CrateType::ProcMacro] } else { vec![CrateType::Rlib] };
 258     let test = scrape_examples_options.map(|opts| opts.scrape_tests).unwrap_or(false);
 259     // plays with error output here!
 260     let sessopts = config::Options {
 261         maybe_sysroot,
 262         search_paths: libs,
 263         crate_types,
 264         lint_opts,
 265         lint_cap,
 266         cg: codegen_options,
 267         externs,
 268         target_triple: target,
 269         unstable_features: UnstableFeatures::from_environment(crate_name.as_deref()),
 270         actually_rustdoc: true,
 271         unstable_opts,
 272         error_format,
 273         diagnostic_width,
 274         edition,
 275         describe_lints,
 276         crate_name,
 277         test,
 278         ..Options::default()
 279     };
 280
 281     interface::Config {
 282         opts: sessopts,
 283         crate_cfg: interface::parse_cfgspecs(cfgs),
 284         crate_check_cfg: interface::parse_check_cfg(check_cfgs),
 285         input,
 286         input_path: cpath,
 287         output_file: None,
 288         output_dir: None,
 289         file_loader: None,
 290         diagnostic_output: DiagnosticOutput::Default,
 291         lint_caps,
 292         parse_sess_created: None,
 293         register_lints: Some(Box::new(crate::lint::register_lints)),
 294         override_queries: Some(|_sess, providers, _external_providers| {
 295             // Most lints will require typechecking, so just don't run them.
 296             providers.lint_mod = |_, _| {};
 297             // Prevent `rustc_typeck::check_crate` from calling `typeck` on all bodies.
 298             providers.typeck_item_bodies = |_, _| {};
 299             // hack so that `used_trait_imports` won't try to call typeck
 300             providers.used_trait_imports = |_, _| {
 301                 static EMPTY_SET: LazyLock<FxHashSet<LocalDefId>> =
 302                     LazyLock::new(FxHashSet::default);
 303                 &EMPTY_SET
 304             };
 305             // In case typeck does end up being called, don't ICE in case there were name resolution errors
 306             providers.typeck = move |tcx, def_id| {
 307                 // Closures' tables come from their outermost function,
 308                 // as they are part of the same "inference environment".
 309                 // This avoids emitting errors for the parent twice (see similar code in `typeck_with_fallback`)
 310                 let typeck_root_def_id = tcx.typeck_root_def_id(def_id.to_def_id()).expect_local();
 311                 if typeck_root_def_id != def_id {
 312                     return tcx.typeck(typeck_root_def_id);
 313                 }
 314
 315                 let hir = tcx.hir();
 316                 let body = hir.body(hir.body_owned_by(def_id));
 317                 debug!("visiting body for {:?}", def_id);
 318                 EmitIgnoredResolutionErrors::new(tcx).visit_body(body);
 319                 (rustc_interface::DEFAULT_QUERY_PROVIDERS.typeck)(tcx, def_id)
 320             };
 321         }),
 322         make_codegen_backend: None,
 323         registry: rustc_driver::diagnostics_registry(),
 324     }
 325 }
 326
 327 pub(crate) fn run_global_ctxt(
 328     tcx: TyCtxt<'_>,
 329     resolver: Rc<RefCell<interface::BoxedResolver>>,
 330     resolver_caches: ResolverCaches,
 331     show_coverage: bool,
 332     render_options: RenderOptions,
 333     output_format: OutputFormat,
 334 ) -> (clean::Crate, RenderOptions, Cache) {
 335     // Certain queries assume that some checks were run elsewhere
 336     // (see https://github.com/rust-lang/rust/pull/73566#issuecomment-656954425),
 337     // so type-check everything other than function bodies in this crate before running lints.
 338
 339     // NOTE: this does not call `tcx.analysis()` so that we won't
 340     // typeck function bodies or run the default rustc lints.
 341     // (see `override_queries` in the `config`)
 342
 343     // HACK(jynelson) this calls an _extremely_ limited subset of `typeck`
 344     // and might break if queries change their assumptions in the future.
 345
 346     // NOTE: This is copy/pasted from typeck/lib.rs and should be kept in sync with those changes.
 347     tcx.sess.time("item_types_checking", || {
 348         tcx.hir().for_each_module(|module| tcx.ensure().check_mod_item_types(module))
 349     });
 350     tcx.sess.abort_if_errors();
 351     tcx.sess.time("missing_docs", || {
 352         rustc_lint::check_crate(tcx, rustc_lint::builtin::MissingDoc::new);
 353     });
 354     tcx.sess.time("check_mod_attrs", || {
 355         tcx.hir().for_each_module(|module| tcx.ensure().check_mod_attrs(module))
 356     });
 357     rustc_passes::stability::check_unused_or_stable_features(tcx);
 358
 359     let auto_traits = resolver_caches
 360         .all_traits
 361         .as_ref()
 362         .expect("`all_traits` are already borrowed")
 363         .iter()
 364         .copied()
 365         .filter(|&trait_def_id| tcx.trait_is_auto(trait_def_id))
 366         .collect();
 367     let access_levels = AccessLevels {
 368         map: tcx.privacy_access_levels(()).map.iter().map(|(k, v)| (k.to_def_id(), *v)).collect(),
 369     };
 370
 371     let mut ctxt = DocContext {
 372         tcx,
 373         resolver,
 374         resolver_caches,
 375         param_env: ParamEnv::empty(),
 376         external_traits: Default::default(),
 377         active_extern_traits: Default::default(),
 378         substs: Default::default(),
 379         impl_trait_bounds: Default::default(),
 380         generated_synthetics: Default::default(),
 381         auto_traits,
 382         cache: Cache::new(access_levels, render_options.document_private),
 383         inlined: FxHashSet::default(),
 384         output_format,
 385         render_options,
 386         show_coverage,
 387     };
 388
 389     // Small hack to force the Sized trait to be present.
 390     //
 391     // Note that in case of `#![no_core]`, the trait is not available.
 392     if let Some(sized_trait_did) = ctxt.tcx.lang_items().sized_trait() {
 393         let sized_trait = build_external_trait(&mut ctxt, sized_trait_did);
 394         ctxt.external_traits
 395             .borrow_mut()
 396             .insert(sized_trait_did, TraitWithExtraInfo { trait_: sized_trait, is_notable: false });
 397     }
 398
 399     debug!("crate: {:?}", tcx.hir().krate());
 400
 401     let mut krate = tcx.sess.time("clean_crate", || clean::krate(&mut ctxt));
 402
 403     if krate.module.doc_value().map(|d| d.is_empty()).unwrap_or(true) {
 404         let help = format!(
 405             "The following guide may be of use:\n\
 406             {}/rustdoc/how-to-write-documentation.html",
 407             crate::DOC_RUST_LANG_ORG_CHANNEL
 408         );
 409         tcx.struct_lint_node(
 410             crate::lint::MISSING_CRATE_LEVEL_DOCS,
 411             DocContext::as_local_hir_id(tcx, krate.module.item_id).unwrap(),
 412             |lint| {
 413                 let mut diag =
 414                     lint.build("no documentation found for this crate's top-level module");
 415                 diag.help(&help);
 416                 diag.emit();
 417             },
 418         );
 419     }
 420
 421     fn report_deprecated_attr(name: &str, diag: &rustc_errors::Handler, sp: Span) {
 422         let mut msg =
 423             diag.struct_span_warn(sp, &format!("the `#![doc({})]` attribute is deprecated", name));
 424         msg.note(
 425             "see issue #44136 <https://github.com/rust-lang/rust/issues/44136> \
 426             for more information",
 427         );
 428
 429         if name == "no_default_passes" {
 430             msg.help("`#![doc(no_default_passes)]` no longer functions; you may want to use `#![doc(document_private_items)]`");
 431         } else if name.starts_with("passes") {
 432             msg.help("`#![doc(passes = \"...\")]` no longer functions; you may want to use `#![doc(document_private_items)]`");
 433         } else if name.starts_with("plugins") {
 434             msg.warn("`#![doc(plugins = \"...\")]` no longer functions; see CVE-2018-1000622 <https://nvd.nist.gov/vuln/detail/CVE-2018-1000622>");
 435         }
 436
 437         msg.emit();
 438     }
 439
 440     // Process all of the crate attributes, extracting plugin metadata along
 441     // with the passes which we are supposed to run.
 442     for attr in krate.module.attrs.lists(sym::doc) {
 443         let diag = ctxt.sess().diagnostic();
 444
 445         let name = attr.name_or_empty();
 446         // `plugins = "..."`, `no_default_passes`, and `passes = "..."` have no effect
 447         if attr.is_word() && name == sym::no_default_passes {
 448             report_deprecated_attr("no_default_passes", diag, attr.span());
 449         } else if attr.value_str().is_some() {
 450             match name {
 451                 sym::passes => {
 452                     report_deprecated_attr("passes = \"...\"", diag, attr.span());
 453                 }
 454                 sym::plugins => {
 455                     report_deprecated_attr("plugins = \"...\"", diag, attr.span());
 456                 }
 457                 _ => (),
 458             }
 459         }
 460
 461         if attr.is_word() && name == sym::document_private_items {
 462             ctxt.render_options.document_private = true;
 463         }
 464     }
 465
 466     info!("Executing passes");
 467
 468     for p in passes::defaults(show_coverage) {
 469         let run = match p.condition {
 470             Always => true,
 471             WhenDocumentPrivate => ctxt.render_options.document_private,
 472             WhenNotDocumentPrivate => !ctxt.render_options.document_private,
 473             WhenNotDocumentHidden => !ctxt.render_options.document_hidden,
 474         };
 475         if run {
 476             debug!("running pass {}", p.pass.name);
 477             krate = tcx.sess.time(p.pass.name, || (p.pass.run)(krate, &mut ctxt));
 478         }
 479     }
 480
 481     tcx.sess.time("check_lint_expectations", || tcx.check_expectations(Some(sym::rustdoc)));
 482
 483     if tcx.sess.diagnostic().has_errors_or_lint_errors().is_some() {
 484         rustc_errors::FatalError.raise();
 485     }
 486
 487     krate = tcx.sess.time("create_format_cache", || Cache::populate(&mut ctxt, krate));
 488
 489     (krate, ctxt.render_options, ctxt.cache)
 490 }
 491
 492 /// Due to <https://github.com/rust-lang/rust/pull/73566>,
 493 /// the name resolution pass may find errors that are never emitted.
 494 /// If typeck is called after this happens, then we'll get an ICE:
 495 /// 'Res::Error found but not reported'. To avoid this, emit the errors now.
 496 struct EmitIgnoredResolutionErrors<'tcx> {
 497     tcx: TyCtxt<'tcx>,
 498 }
 499
 500 impl<'tcx> EmitIgnoredResolutionErrors<'tcx> {
 501     fn new(tcx: TyCtxt<'tcx>) -> Self {
 502         Self { tcx }
 503     }
 504 }
 505
 506 impl<'tcx> Visitor<'tcx> for EmitIgnoredResolutionErrors<'tcx> {
 507     type NestedFilter = nested_filter::OnlyBodies;
 508
 509     fn nested_visit_map(&mut self) -> Self::Map {
 510         // We need to recurse into nested closures,
 511         // since those will fallback to the parent for type checking.
 512         self.tcx.hir()
 513     }
 514
 515     fn visit_path(&mut self, path: &'tcx Path<'_>, _id: HirId) {
 516         debug!("visiting path {:?}", path);
 517         if path.res == Res::Err {
 518             // We have less context here than in rustc_resolve,
 519             // so we can only emit the name and span.
 520             // However we can give a hint that rustc_resolve will have more info.
 521             let label = format!(
 522                 "could not resolve path `{}`",
 523                 path.segments
 524                     .iter()
 525                     .map(|segment| segment.ident.as_str())
 526                     .intersperse("::")
 527                     .collect::<String>()
 528             );
 529             let mut err = rustc_errors::struct_span_err!(
 530                 self.tcx.sess,
 531                 path.span,
 532                 E0433,
 533                 "failed to resolve: {}",
 534                 label
 535             );
 536             err.span_label(path.span, label);
 537             err.note("this error was originally ignored because you are running `rustdoc`");
 538             err.note("try running again with `rustc` or `cargo check` and you may get a more detailed error");
 539             err.emit();
 540         }
 541         // We could have an outer resolution that succeeded,
 542         // but with generic parameters that failed.
 543         // Recurse into the segments so we catch those too.
 544         intravisit::walk_path(self, path);
 545     }
 546 }
 547
 548 /// `DefId` or parameter index (`ty::ParamTy.index`) of a synthetic type parameter
 549 /// for `impl Trait` in argument position.
 550 #[derive(Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
 551 pub(crate) enum ImplTraitParam {
 552     DefId(DefId),
 553     ParamIndex(u32),
 554 }
 555
 556 impl From<DefId> for ImplTraitParam {
 557     fn from(did: DefId) -> Self {
 558         ImplTraitParam::DefId(did)
 559     }
 560 }
 561
 562 impl From<u32> for ImplTraitParam {
 563     fn from(idx: u32) -> Self {
 564         ImplTraitParam::ParamIndex(idx)
 565     }
 566 }