rustdoc/
core.rs

1use std::sync::{Arc, LazyLock};
2use std::{io, mem};
3
4use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
5use rustc_data_structures::unord::UnordSet;
6use rustc_driver::USING_INTERNAL_FEATURES;
7use rustc_errors::TerminalUrl;
8use rustc_errors::annotate_snippet_emitter_writer::AnnotateSnippetEmitter;
9use rustc_errors::codes::*;
10use rustc_errors::emitter::{DynEmitter, HumanReadableErrorType, OutputTheme, stderr_destination};
11use rustc_errors::json::JsonEmitter;
12use rustc_feature::UnstableFeatures;
13use rustc_hir::def::Res;
14use rustc_hir::def_id::{DefId, DefIdMap, DefIdSet, LocalDefId};
15use rustc_hir::intravisit::{self, Visitor};
16use rustc_hir::{HirId, Path};
17use rustc_lint::{MissingDoc, late_lint_mod};
18use rustc_middle::hir::nested_filter;
19use rustc_middle::ty::{self, ParamEnv, Ty, TyCtxt};
20use rustc_session::config::{
21    self, CrateType, ErrorOutputType, Input, OutputType, OutputTypes, ResolveDocLinks,
22};
23pub(crate) use rustc_session::config::{Options, UnstableOptions};
24use rustc_session::{Session, lint};
25use rustc_span::source_map;
26use rustc_span::symbol::sym;
27use tracing::{debug, info};
28
29use crate::clean::inline::build_trait;
30use crate::clean::{self, ItemId};
31use crate::config::{Options as RustdocOptions, OutputFormat, RenderOptions};
32use crate::formats::cache::Cache;
33use crate::html::macro_expansion::{ExpandedCode, source_macro_expansion};
34use crate::passes;
35use crate::passes::Condition::*;
36use crate::passes::collect_intra_doc_links::LinkCollector;
37
38pub(crate) struct DocContext<'tcx> {
39    pub(crate) tcx: TyCtxt<'tcx>,
40    /// Used for normalization.
41    ///
42    /// Most of this logic is copied from rustc_lint::late.
43    pub(crate) param_env: ParamEnv<'tcx>,
44    /// Later on moved through `clean::Crate` into `cache`
45    pub(crate) external_traits: FxIndexMap<DefId, clean::Trait>,
46    /// Used while populating `external_traits` to ensure we don't process the same trait twice at
47    /// the same time.
48    pub(crate) active_extern_traits: DefIdSet,
49    /// The current set of parameter instantiations for expanding type aliases at the HIR level.
50    ///
51    /// Maps from the `DefId` of a lifetime or type parameter to the
52    /// generic argument it's currently instantiated to in this context.
53    // FIXME(#82852): We don't record const params since we don't visit const exprs at all and
54    // therefore wouldn't use the corresp. generic arg anyway. Add support for them.
55    pub(crate) args: DefIdMap<clean::GenericArg>,
56    pub(crate) current_type_aliases: DefIdMap<usize>,
57    /// Table synthetic type parameter for `impl Trait` in argument position -> bounds
58    pub(crate) impl_trait_bounds: FxHashMap<ImplTraitParam, Vec<clean::GenericBound>>,
59
60    // FIXME: I'm pretty that the only reason we "need" these caches is because we also invoke
61    //        `synthesize_auto_trait_and_blanket_impls` on all impls(!) for primitive types
62    //        instead of calling it only once per primitive type (see also #97129).
63    //        Get rid of that jank and remove both caches!
64    //
65    /// The set of auto-trait impls generated so far; identified by `(self_ty, trait_def_id)`.
66    pub(crate) synthetic_auto_trait_impls: FxHashSet<(Ty<'tcx>, DefId)>,
67    /// The set of blanket impls generated so far; identified by `(self_ty, trait_def_id)`.
68    pub(crate) synthetic_blanket_impls: FxHashSet<(Ty<'tcx>, DefId)>,
69
70    /// All auto traits in the (visible) crate graph.
71    pub(crate) auto_traits: Vec<DefId>,
72    /// This same cache is used throughout rustdoc, including in [`crate::html::render`].
73    pub(crate) cache: Cache,
74    /// Used by [`clean::inline`] to tell if an item has already been inlined.
75    pub(crate) inlined: FxHashSet<ItemId>,
76    /// Used by `calculate_doc_coverage`.
77    pub(crate) output_format: OutputFormat,
78}
79
80impl<'tcx> DocContext<'tcx> {
81    pub(crate) fn sess(&self) -> &'tcx Session {
82        self.tcx.sess
83    }
84
85    pub(crate) fn with_param_env<T, F: FnOnce(&mut Self) -> T>(
86        &mut self,
87        def_id: DefId,
88        f: F,
89    ) -> T {
90        self.with_exact_param_env(self.tcx.param_env(def_id), f)
91    }
92
93    pub(crate) fn with_exact_param_env<T, F: FnOnce(&mut Self) -> T>(
94        &mut self,
95        param_env: ParamEnv<'tcx>,
96        f: F,
97    ) -> T {
98        let old_param_env = mem::replace(&mut self.param_env, param_env);
99        let ret = f(self);
100        self.param_env = old_param_env;
101        ret
102    }
103
104    pub(crate) fn typing_env(&self) -> ty::TypingEnv<'tcx> {
105        ty::TypingEnv::new(self.param_env, ty::TypingMode::non_body_analysis())
106    }
107
108    /// Call the closure with the given parameters set as
109    /// the generic parameters for a type alias' RHS.
110    pub(crate) fn enter_alias<F, R>(
111        &mut self,
112        args: DefIdMap<clean::GenericArg>,
113        def_id: DefId,
114        f: F,
115    ) -> R
116    where
117        F: FnOnce(&mut Self) -> R,
118    {
119        let old_args = mem::replace(&mut self.args, args);
120        *self.current_type_aliases.entry(def_id).or_insert(0) += 1;
121        let r = f(self);
122        self.args = old_args;
123        if let Some(count) = self.current_type_aliases.get_mut(&def_id) {
124            *count -= 1;
125            if *count == 0 {
126                self.current_type_aliases.remove(&def_id);
127            }
128        }
129        r
130    }
131
132    /// Like `tcx.local_def_id_to_hir_id()`, but skips calling it on fake DefIds.
133    /// (This avoids a slice-index-out-of-bounds panic.)
134    pub(crate) fn as_local_hir_id(tcx: TyCtxt<'_>, item_id: ItemId) -> Option<HirId> {
135        match item_id {
136            ItemId::DefId(real_id) => {
137                real_id.as_local().map(|def_id| tcx.local_def_id_to_hir_id(def_id))
138            }
139            // FIXME: Can this be `Some` for `Auto` or `Blanket`?
140            _ => None,
141        }
142    }
143
144    /// Returns `true` if the JSON output format is enabled for generating the crate content.
145    ///
146    /// If another option like `--show-coverage` is enabled, it will return `false`.
147    pub(crate) fn is_json_output(&self) -> bool {
148        self.output_format == OutputFormat::IrJson
149    }
150
151    /// If `--document-private-items` was passed to rustdoc.
152    pub(crate) fn document_private(&self) -> bool {
153        self.cache.document_private
154    }
155
156    /// If `--document-hidden-items` was passed to rustdoc.
157    pub(crate) fn document_hidden(&self) -> bool {
158        self.cache.document_hidden
159    }
160}
161
162/// Creates a new `DiagCtxt` that can be used to emit warnings and errors.
163///
164/// If the given `error_format` is `ErrorOutputType::Json` and no `SourceMap` is given, a new one
165/// will be created for the `DiagCtxt`.
166pub(crate) fn new_dcx(
167    error_format: ErrorOutputType,
168    source_map: Option<Arc<source_map::SourceMap>>,
169    diagnostic_width: Option<usize>,
170    unstable_opts: &UnstableOptions,
171) -> rustc_errors::DiagCtxt {
172    let emitter: Box<DynEmitter> = match error_format {
173        ErrorOutputType::HumanReadable { kind, color_config } => match kind {
174            HumanReadableErrorType { short, unicode } => Box::new(
175                AnnotateSnippetEmitter::new(stderr_destination(color_config))
176                    .sm(source_map.map(|sm| sm as _))
177                    .short_message(short)
178                    .diagnostic_width(diagnostic_width)
179                    .track_diagnostics(unstable_opts.track_diagnostics)
180                    .theme(if unicode { OutputTheme::Unicode } else { OutputTheme::Ascii })
181                    .ui_testing(unstable_opts.ui_testing),
182            ),
183        },
184        ErrorOutputType::Json { pretty, json_rendered, color_config } => {
185            let source_map = source_map.unwrap_or_else(|| {
186                Arc::new(source_map::SourceMap::new(source_map::FilePathMapping::empty()))
187            });
188            Box::new(
189                JsonEmitter::new(
190                    Box::new(io::BufWriter::new(io::stderr())),
191                    Some(source_map),
192                    pretty,
193                    json_rendered,
194                    color_config,
195                )
196                .ui_testing(unstable_opts.ui_testing)
197                .diagnostic_width(diagnostic_width)
198                .track_diagnostics(unstable_opts.track_diagnostics)
199                .terminal_url(TerminalUrl::No),
200            )
201        }
202    };
203
204    rustc_errors::DiagCtxt::new(emitter).with_flags(unstable_opts.dcx_flags(true))
205}
206
207/// Parse, resolve, and typecheck the given crate.
208pub(crate) fn create_config(
209    input: Input,
210    RustdocOptions {
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        sysroot,
224        lint_opts,
225        describe_lints,
226        lint_cap,
227        scrape_examples_options,
228        remap_path_prefix,
229        remap_path_scope,
230        target_modifiers,
231        ..
232    }: RustdocOptions,
233    render_options: &RenderOptions,
234) -> rustc_interface::Config {
235    // Add the doc cfg into the doc build.
236    cfgs.push("doc".to_string());
237
238    // By default, rustdoc ignores all lints.
239    // Specifically unblock lints relevant to documentation or the lint machinery itself.
240    let mut lints_to_show = vec![
241        // it's unclear whether these should be part of rustdoc directly (#77364)
242        rustc_lint::builtin::MISSING_DOCS.name.to_string(),
243        rustc_lint::builtin::INVALID_DOC_ATTRIBUTES.name.to_string(),
244        rustc_lint::builtin::UNUSED_DOC_COMMENTS.name.to_string(),
245        // these are definitely not part of rustdoc, but we want to warn on them anyway.
246        rustc_lint::builtin::RENAMED_AND_REMOVED_LINTS.name.to_string(),
247        rustc_lint::builtin::UNKNOWN_LINTS.name.to_string(),
248        rustc_lint::builtin::UNEXPECTED_CFGS.name.to_string(),
249        rustc_lint::builtin::DUPLICATE_FEATURES.name.to_string(),
250        rustc_lint::builtin::UNUSED_FEATURES.name.to_string(),
251        rustc_lint::builtin::STABLE_FEATURES.name.to_string(),
252        // this lint is needed to support `#[expect]` attributes
253        rustc_lint::builtin::UNFULFILLED_LINT_EXPECTATIONS.name.to_string(),
254    ];
255    lints_to_show.extend(crate::lint::RUSTDOC_LINTS.iter().map(|lint| lint.name.to_string()));
256
257    let (lint_opts, lint_caps) = crate::lint::init_lints(lints_to_show, lint_opts, |lint| {
258        Some((lint.name_lower(), lint::Allow))
259    });
260
261    let crate_types =
262        if proc_macro_crate { vec![CrateType::ProcMacro] } else { vec![CrateType::Rlib] };
263    let resolve_doc_links = if render_options.document_private {
264        ResolveDocLinks::All
265    } else {
266        ResolveDocLinks::Exported
267    };
268    let test = scrape_examples_options.map(|opts| opts.scrape_tests).unwrap_or(false);
269    // plays with error output here!
270    let sessopts = config::Options {
271        sysroot,
272        search_paths: libs,
273        crate_types,
274        lint_opts,
275        lint_cap,
276        cg: codegen_options,
277        externs,
278        target_triple: target,
279        unstable_features: UnstableFeatures::from_environment(crate_name.as_deref()),
280        actually_rustdoc: true,
281        resolve_doc_links,
282        unstable_opts,
283        error_format,
284        diagnostic_width,
285        edition,
286        describe_lints,
287        crate_name,
288        test,
289        remap_path_prefix,
290        remap_path_scope,
291        output_types: if let Some(file) = render_options.dep_info() {
292            OutputTypes::new(&[(OutputType::DepInfo, file.cloned())])
293        } else {
294            OutputTypes::new(&[])
295        },
296        target_modifiers,
297        ..Options::default()
298    };
299
300    rustc_interface::Config {
301        opts: sessopts,
302        crate_cfg: cfgs,
303        crate_check_cfg: check_cfgs,
304        input,
305        output_file: None,
306        output_dir: if render_options.output_to_stdout {
307            None
308        } else {
309            Some(render_options.output.clone())
310        },
311        file_loader: None,
312        lint_caps,
313        psess_created: None,
314        track_state: None,
315        register_lints: Some(Box::new(crate::lint::register_lints)),
316        override_queries: Some(|_sess, providers| {
317            // We do not register late module lints, so this only runs `MissingDoc`.
318            // Most lints will require typechecking, so just don't run them.
319            providers.queries.lint_mod =
320                |tcx, module_def_id| late_lint_mod(tcx, module_def_id, MissingDoc);
321            // hack so that `used_trait_imports` won't try to call typeck
322            providers.queries.used_trait_imports = |_, _| {
323                static EMPTY_SET: LazyLock<UnordSet<LocalDefId>> = LazyLock::new(UnordSet::default);
324                &EMPTY_SET
325            };
326            // In case typeck does end up being called, don't ICE in case there were name resolution errors
327            providers.queries.typeck_root = move |tcx, def_id| {
328                // Panic before code below breaks in case of someone calls typeck_root directly
329                assert!(!tcx.is_typeck_child(def_id.to_def_id()));
330
331                let body = tcx.hir_body_owned_by(def_id);
332                debug!("visiting body for {def_id:?}");
333                EmitIgnoredResolutionErrors::new(tcx).visit_body(body);
334                (rustc_interface::DEFAULT_QUERY_PROVIDERS.queries.typeck_root)(tcx, def_id)
335            };
336        }),
337        extra_symbols: Vec::new(),
338        make_codegen_backend: None,
339        ice_file: None,
340        using_internal_features: &USING_INTERNAL_FEATURES,
341    }
342}
343
344pub(crate) fn run_global_ctxt(
345    tcx: TyCtxt<'_>,
346    show_coverage: bool,
347    render_options: RenderOptions,
348    output_format: OutputFormat,
349) -> (clean::Crate, RenderOptions, Cache, FxHashMap<rustc_span::BytePos, Vec<ExpandedCode>>) {
350    // Certain queries assume that some checks were run elsewhere
351    // (see https://github.com/rust-lang/rust/pull/73566#issuecomment-656954425),
352    // so type-check everything other than function bodies in this crate before running lints.
353
354    let expanded_macros = {
355        // We need for these variables to be removed to ensure that the `Crate` won't be "stolen"
356        // anymore.
357        let krate = &*tcx.resolver_for_lowering().1.borrow();
358
359        source_macro_expansion(&krate, &render_options, output_format, tcx.sess.source_map())
360    };
361
362    // NOTE: this does not call `tcx.analysis()` so that we won't
363    // typeck function bodies or run the default rustc lints.
364    // (see `override_queries` in the `config`)
365
366    // NOTE: These are copy/pasted from typeck/lib.rs and should be kept in sync with those changes.
367    tcx.sess.time("wf_checking", || tcx.ensure_ok().check_type_wf(()));
368
369    tcx.dcx().abort_if_errors();
370
371    tcx.sess.time("missing_docs", || rustc_lint::check_crate(tcx));
372    tcx.sess.time("check_mod_attrs", || {
373        tcx.hir_for_each_module(|module| tcx.ensure_ok().check_mod_attrs(module))
374    });
375    rustc_passes::stability::check_unused_or_stable_features(tcx);
376
377    let auto_traits =
378        tcx.visible_traits().filter(|&trait_def_id| tcx.trait_is_auto(trait_def_id)).collect();
379
380    let mut ctxt = DocContext {
381        tcx,
382        param_env: ParamEnv::empty(),
383        external_traits: Default::default(),
384        active_extern_traits: Default::default(),
385        args: Default::default(),
386        current_type_aliases: Default::default(),
387        impl_trait_bounds: Default::default(),
388        synthetic_auto_trait_impls: Default::default(),
389        synthetic_blanket_impls: Default::default(),
390        auto_traits,
391        cache: Cache::new(render_options.document_private, render_options.document_hidden),
392        inlined: FxHashSet::default(),
393        output_format,
394    };
395
396    for cnum in tcx.crates(()) {
397        crate::visit_lib::lib_embargo_visit_item(&mut ctxt, cnum.as_def_id());
398    }
399
400    // Small hack to force the Sized trait to be present.
401    //
402    // Note that in case of `#![no_core]`, the trait is not available.
403    if let Some(sized_trait_did) = ctxt.tcx.lang_items().sized_trait() {
404        let sized_trait = build_trait(&mut ctxt, sized_trait_did);
405        ctxt.external_traits.insert(sized_trait_did, sized_trait);
406    }
407
408    let mut krate = tcx.sess.time("clean_crate", || clean::krate(&mut ctxt));
409
410    if krate.module.doc_value().is_empty() {
411        let help = format!(
412            "The following guide may be of use:\n\
413            {}/rustdoc/how-to-write-documentation.html",
414            crate::DOC_RUST_LANG_ORG_VERSION
415        );
416        tcx.emit_node_lint(
417            crate::lint::MISSING_CRATE_LEVEL_DOCS,
418            DocContext::as_local_hir_id(tcx, krate.module.item_id).unwrap(),
419            rustc_errors::DiagDecorator(|lint| {
420                if let Some(local_def_id) = krate.module.item_id.as_local_def_id() {
421                    lint.span(tcx.def_span(local_def_id));
422                }
423                lint.primary_message("no documentation found for this crate's top-level module");
424                lint.help(help);
425            }),
426        );
427    }
428
429    info!("Executing passes");
430
431    let mut visited = FxHashMap::default();
432    let mut ambiguous = FxIndexMap::default();
433
434    for p in passes::defaults(show_coverage) {
435        let run = match p.condition {
436            Always => true,
437            WhenDocumentPrivate => ctxt.document_private(),
438            WhenNotDocumentPrivate => !ctxt.document_private(),
439            WhenNotDocumentHidden => !ctxt.document_hidden(),
440        };
441        if run {
442            debug!("running pass {}", p.pass.name);
443            if let Some(run_fn) = p.pass.run {
444                krate = tcx.sess.time(p.pass.name, || run_fn(krate, &mut ctxt));
445            } else {
446                let (k, LinkCollector { visited_links, ambiguous_links, .. }) =
447                    passes::collect_intra_doc_links::collect_intra_doc_links(krate, &mut ctxt);
448                krate = k;
449                visited = visited_links;
450                ambiguous = ambiguous_links;
451            }
452        }
453    }
454
455    tcx.sess.time("check_lint_expectations", || tcx.check_expectations(Some(sym::rustdoc)));
456
457    krate =
458        tcx.sess.time("create_format_cache", || Cache::populate(&mut ctxt, krate, &render_options));
459
460    let mut collector =
461        LinkCollector { cx: &mut ctxt, visited_links: visited, ambiguous_links: ambiguous };
462    collector.resolve_ambiguities();
463
464    tcx.dcx().abort_if_errors();
465
466    (krate, render_options, ctxt.cache, expanded_macros)
467}
468
469/// Due to <https://github.com/rust-lang/rust/pull/73566>,
470/// the name resolution pass may find errors that are never emitted.
471/// If typeck is called after this happens, then we'll get an ICE:
472/// 'Res::Error found but not reported'. To avoid this, emit the errors now.
473struct EmitIgnoredResolutionErrors<'tcx> {
474    tcx: TyCtxt<'tcx>,
475}
476
477impl<'tcx> EmitIgnoredResolutionErrors<'tcx> {
478    fn new(tcx: TyCtxt<'tcx>) -> Self {
479        Self { tcx }
480    }
481}
482
483impl<'tcx> Visitor<'tcx> for EmitIgnoredResolutionErrors<'tcx> {
484    type NestedFilter = nested_filter::OnlyBodies;
485
486    fn maybe_tcx(&mut self) -> Self::MaybeTyCtxt {
487        // We need to recurse into nested closures,
488        // since those will fallback to the parent for type checking.
489        self.tcx
490    }
491
492    fn visit_path(&mut self, path: &Path<'tcx>, _id: HirId) {
493        debug!("visiting path {path:?}");
494        if path.res == Res::Err {
495            // We have less context here than in rustc_resolve,
496            // so we can only emit the name and span.
497            // However we can give a hint that rustc_resolve will have more info.
498            let label = format!(
499                "could not resolve path `{}`",
500                path.segments
501                    .iter()
502                    .map(|segment| segment.ident.as_str())
503                    .intersperse("::")
504                    .collect::<String>()
505            );
506            rustc_errors::struct_span_code_err!(
507                self.tcx.dcx(),
508                path.span,
509                E0433,
510                "failed to resolve: {label}",
511            )
512            .with_span_label(path.span, label)
513            .with_note("this error was originally ignored because you are running `rustdoc`")
514            .with_note("try running again with `rustc` or `cargo check` and you may get a more detailed error")
515            .emit();
516        }
517        // We could have an outer resolution that succeeded,
518        // but with generic parameters that failed.
519        // Recurse into the segments so we catch those too.
520        intravisit::walk_path(self, path);
521    }
522}
523
524/// `DefId` or parameter index (`ty::ParamTy.index`) of a synthetic type parameter
525/// for `impl Trait` in argument position.
526#[derive(Clone, Copy, PartialEq, Eq, Hash)]
527pub(crate) enum ImplTraitParam {
528    DefId(DefId),
529    ParamIndex(u32),
530}
531
532impl From<DefId> for ImplTraitParam {
533    fn from(did: DefId) -> Self {
534        ImplTraitParam::DefId(did)
535    }
536}
537
538impl From<u32> for ImplTraitParam {
539    fn from(idx: u32) -> Self {
540        ImplTraitParam::ParamIndex(idx)
541    }
542}
rustdoc/core.rs

rustdoc/
core.rs
