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 as lint;
18use rustc_lint::{MissingDoc, late_lint_mod};
19use rustc_middle::hir::nested_filter;
20use rustc_middle::ty::{self, ParamEnv, Ty, TyCtxt};
21use rustc_session::Session;
22use rustc_session::config::{
23    self, ErrorOutputType, Input, OutputType, OutputTypes, ResolveDocLinks,
24};
25pub(crate) use rustc_session::config::{Options, UnstableOptions};
26use rustc_span::source_map;
27use rustc_span::symbol::sym;
28use rustc_structures::CrateType;
29use tracing::debug;
30
31use crate::clean::inline::build_trait;
32use crate::clean::{self, ItemId};
33use crate::config::{Options as RustdocOptions, OutputFormat, RenderOptions};
34use crate::formats::cache::Cache;
35use crate::html::macro_expansion::{ExpandedCode, source_macro_expansion};
36use crate::passes;
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        prints,
228        scrape_examples_options,
229        remap_path_prefix,
230        remap_path_scope,
231        target_modifiers,
232        ..
233    }: RustdocOptions,
234    render_options: &RenderOptions,
235) -> rustc_interface::Config {
236    // Add the doc cfg into the doc build.
237    cfgs.push("doc".to_string());
238
239    // By default, rustdoc ignores all lints.
240    // Specifically unblock lints relevant to documentation or the lint machinery itself.
241    let mut lints_to_show = vec![
242        // it's unclear whether these should be part of rustdoc directly (#77364)
243        rustc_lint::builtin::MISSING_DOCS.name.to_string(),
244        rustc_lint::builtin::INVALID_DOC_ATTRIBUTES.name.to_string(),
245        rustc_lint::builtin::UNUSED_DOC_COMMENTS.name.to_string(),
246        // these are definitely not part of rustdoc, but we want to warn on them anyway.
247        rustc_lint::builtin::RENAMED_AND_REMOVED_LINTS.name.to_string(),
248        rustc_lint::builtin::UNKNOWN_LINTS.name.to_string(),
249        rustc_lint::builtin::UNEXPECTED_CFGS.name.to_string(),
250        rustc_lint::builtin::DUPLICATE_FEATURES.name.to_string(),
251        rustc_lint::builtin::UNUSED_FEATURES.name.to_string(),
252        rustc_lint::builtin::STABLE_FEATURES.name.to_string(),
253        // this lint is needed to support `#[expect]` attributes
254        rustc_lint::builtin::UNFULFILLED_LINT_EXPECTATIONS.name.to_string(),
255    ];
256    lints_to_show.extend(crate::lint::RUSTDOC_LINTS.iter().map(|lint| lint.name.to_string()));
257
258    let (lint_opts, lint_caps) = crate::lint::init_lints(lints_to_show, lint_opts, |lint| {
259        Some((lint.name_lower(), lint::Allow))
260    });
261
262    let crate_types =
263        if proc_macro_crate { vec![CrateType::ProcMacro] } else { vec![CrateType::Rlib] };
264    let resolve_doc_links = if render_options.document_private {
265        ResolveDocLinks::All
266    } else {
267        ResolveDocLinks::Exported
268    };
269    let test = scrape_examples_options.map(|opts| opts.scrape_tests).unwrap_or(false);
270    // plays with error output here!
271    let sessopts = config::Options {
272        sysroot,
273        search_paths: libs,
274        crate_types,
275        lint_opts,
276        lint_cap,
277        cg: codegen_options,
278        externs,
279        target_triple: target,
280        unstable_features: UnstableFeatures::from_environment(crate_name.as_deref()),
281        actually_rustdoc: true,
282        resolve_doc_links,
283        unstable_opts,
284        error_format,
285        diagnostic_width,
286        edition,
287        describe_lints,
288        prints,
289        crate_name,
290        test,
291        remap_path_prefix,
292        remap_path_scope,
293        output_types: if let Some(file) = render_options.dep_info() {
294            OutputTypes::new(&[(OutputType::DepInfo, file.cloned())])
295        } else {
296            OutputTypes::new(&[])
297        },
298        target_modifiers,
299        ..Options::default()
300    };
301
302    rustc_interface::Config {
303        opts: sessopts,
304        crate_cfg: cfgs,
305        crate_check_cfg: check_cfgs,
306        input,
307        output_file: None,
308        output_dir: if render_options.output_to_stdout {
309            None
310        } else {
311            Some(render_options.output.clone())
312        },
313        file_loader: None,
314        lint_caps,
315        psess_created: None,
316        track_state: None,
317        register_lints: Some(Box::new(crate::lint::register_lints)),
318        override_queries: Some(|_sess, providers| {
319            // We do not register late module lints, so this only runs `MissingDoc`.
320            // Most lints will require typechecking, so just don't run them.
321            providers.queries.lint_mod =
322                |tcx, module_def_id| late_lint_mod(tcx, module_def_id, MissingDoc);
323            // hack so that `used_trait_imports` won't try to call typeck
324            providers.queries.used_trait_imports = |_, _| {
325                static EMPTY_SET: LazyLock<UnordSet<LocalDefId>> = LazyLock::new(UnordSet::default);
326                &EMPTY_SET
327            };
328            // In case typeck does end up being called, don't ICE in case there were name resolution errors
329            providers.queries.typeck_root = move |tcx, def_id| {
330                // Panic before code below breaks in case of someone calls typeck_root directly
331                assert!(!tcx.is_typeck_child(def_id.to_def_id()));
332
333                let body = tcx.hir_body_owned_by(def_id);
334                debug!("visiting body for {def_id:?}");
335                EmitIgnoredResolutionErrors::new(tcx).visit_body(body);
336                (rustc_interface::DEFAULT_QUERY_PROVIDERS.queries.typeck_root)(tcx, def_id)
337            };
338        }),
339        extra_symbols: Vec::new(),
340        make_codegen_backend: None,
341        ice_file: None,
342        using_internal_features: &USING_INTERNAL_FEATURES,
343    }
344}
345
346pub(crate) fn run_global_ctxt(
347    tcx: TyCtxt<'_>,
348    show_coverage: bool,
349    render_options: RenderOptions,
350    output_format: OutputFormat,
351) -> (clean::Crate, RenderOptions, Cache, FxHashMap<rustc_span::BytePos, Vec<ExpandedCode>>) {
352    // Certain queries assume that some checks were run elsewhere
353    // (see https://github.com/rust-lang/rust/pull/73566#issuecomment-656954425),
354    // so type-check everything other than function bodies in this crate before running lints.
355
356    let expanded_macros = {
357        // We need for these variables to be removed to ensure that the `Crate` won't be "stolen"
358        // anymore.
359        let krate = &*tcx.resolver_for_lowering().1.borrow();
360
361        source_macro_expansion(&krate, &render_options, output_format, tcx.sess.source_map())
362    };
363
364    // NOTE: this does not call `tcx.analysis()` so that we won't
365    // typeck function bodies or run the default rustc lints.
366    // (see `override_queries` in the `config`)
367
368    // NOTE: These are copy/pasted from typeck/lib.rs and should be kept in sync with those changes.
369    tcx.sess.time("wf_checking", || tcx.ensure_ok().check_type_wf(()));
370
371    tcx.dcx().abort_if_errors();
372
373    tcx.sess.time("missing_docs", || rustc_lint::check_crate(tcx));
374    tcx.sess.time("check_mod_attrs", || {
375        tcx.hir_for_each_module(|module| tcx.ensure_ok().check_mod_attrs(module))
376    });
377    rustc_passes::stability::check_unused_or_stable_features(tcx);
378
379    let auto_traits =
380        tcx.visible_traits().filter(|&trait_def_id| tcx.trait_is_auto(trait_def_id)).collect();
381
382    let mut ctxt = DocContext {
383        tcx,
384        param_env: ParamEnv::empty(),
385        external_traits: Default::default(),
386        active_extern_traits: Default::default(),
387        args: Default::default(),
388        current_type_aliases: Default::default(),
389        impl_trait_bounds: Default::default(),
390        synthetic_auto_trait_impls: Default::default(),
391        synthetic_blanket_impls: Default::default(),
392        auto_traits,
393        cache: Cache::new(render_options.document_private, render_options.document_hidden),
394        inlined: FxHashSet::default(),
395        output_format,
396    };
397
398    for cnum in tcx.crates(()) {
399        crate::visit_lib::lib_embargo_visit_item(&mut ctxt, cnum.as_def_id());
400    }
401
402    // Small hack to force the Sized trait to be present.
403    //
404    // Note that in case of `#![no_core]`, the trait is not available.
405    if let Some(sized_trait_did) = ctxt.tcx.lang_items().sized_trait() {
406        let sized_trait = build_trait(&mut ctxt, sized_trait_did);
407        ctxt.external_traits.insert(sized_trait_did, sized_trait);
408    }
409
410    let mut krate = tcx.sess.time("clean_crate", || clean::krate(&mut ctxt));
411
412    if krate.module.doc_value().is_empty() {
413        let help = format!(
414            "The following guide may be of use:\n\
415            {}/rustdoc/how-to-write-documentation.html",
416            crate::DOC_RUST_LANG_ORG_VERSION
417        );
418        tcx.emit_node_lint(
419            crate::lint::MISSING_CRATE_LEVEL_DOCS,
420            DocContext::as_local_hir_id(tcx, krate.module.item_id).unwrap(),
421            rustc_errors::DiagDecorator(|lint| {
422                if let Some(local_def_id) = krate.module.item_id.as_local_def_id() {
423                    lint.span(tcx.def_span(local_def_id));
424                }
425                lint.primary_message("no documentation found for this crate's top-level module");
426                lint.help(help);
427            }),
428        );
429    }
430
431    let store;
432    (krate, store) = passes::run(krate, &mut ctxt, show_coverage);
433
434    if show_coverage
435        && let Err(error) = crate::calculate_doc_coverage::run(&krate, &mut ctxt, &render_options)
436    {
437        eprintln!("{error}");
438        std::process::exit(1);
439    }
440
441    tcx.sess.time("check_lint_expectations", || tcx.check_expectations(Some(sym::rustdoc)));
442
443    krate =
444        tcx.sess.time("create_format_cache", || Cache::populate(&mut ctxt, krate, &render_options));
445
446    passes::finalize(&mut ctxt, store);
447
448    tcx.dcx().abort_if_errors();
449
450    (krate, render_options, ctxt.cache, expanded_macros)
451}
452
453/// Due to <https://github.com/rust-lang/rust/pull/73566>,
454/// the name resolution pass may find errors that are never emitted.
455/// If typeck is called after this happens, then we'll get an ICE:
456/// 'Res::Error found but not reported'. To avoid this, emit the errors now.
457struct EmitIgnoredResolutionErrors<'tcx> {
458    tcx: TyCtxt<'tcx>,
459}
460
461impl<'tcx> EmitIgnoredResolutionErrors<'tcx> {
462    fn new(tcx: TyCtxt<'tcx>) -> Self {
463        Self { tcx }
464    }
465}
466
467impl<'tcx> Visitor<'tcx> for EmitIgnoredResolutionErrors<'tcx> {
468    type NestedFilter = nested_filter::OnlyBodies;
469
470    fn maybe_tcx(&mut self) -> Self::MaybeTyCtxt {
471        // We need to recurse into nested closures,
472        // since those will fallback to the parent for type checking.
473        self.tcx
474    }
475
476    fn visit_path(&mut self, path: &Path<'tcx>, _id: HirId) {
477        debug!("visiting path {path:?}");
478        if path.res == Res::Err {
479            // We have less context here than in rustc_resolve,
480            // so we can only emit the name and span.
481            // However we can give a hint that rustc_resolve will have more info.
482            let label = format!(
483                "could not resolve path `{}`",
484                path.segments
485                    .iter()
486                    .map(|segment| segment.ident.as_str())
487                    .intersperse("::")
488                    .collect::<String>()
489            );
490            rustc_errors::struct_span_code_err!(
491                self.tcx.dcx(),
492                path.span,
493                E0433,
494                "failed to resolve: {label}",
495            )
496            .with_span_label(path.span, label)
497            .with_note("this error was originally ignored because you are running `rustdoc`")
498            .with_note("try running again with `rustc` or `cargo check` and you may get a more detailed error")
499            .emit();
500        }
501        // We could have an outer resolution that succeeded,
502        // but with generic parameters that failed.
503        // Recurse into the segments so we catch those too.
504        intravisit::walk_path(self, path);
505    }
506}
507
508/// `DefId` or parameter index (`ty::ParamTy.index`) of a synthetic type parameter
509/// for `impl Trait` in argument position.
510#[derive(Clone, Copy, PartialEq, Eq, Hash)]
511pub(crate) enum ImplTraitParam {
512    DefId(DefId),
513    ParamIndex(u32),
514}
515
516impl From<DefId> for ImplTraitParam {
517    fn from(did: DefId) -> Self {
518        ImplTraitParam::DefId(did)
519    }
520}
521
522impl From<u32> for ImplTraitParam {
523    fn from(idx: u32) -> Self {
524        ImplTraitParam::ParamIndex(idx)
525    }
526}
rustdoc/core.rs

rustdoc/
core.rs
