1 //! The Rust AST Visitor. Extracts useful information and massages it into a form
2 //! usable for `clean`.
4 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
6 use rustc_hir::def::{DefKind, Res};
7 use rustc_hir::def_id::DefId;
8 use rustc_hir::intravisit::{walk_item, Visitor};
10 use rustc_hir::CRATE_HIR_ID;
11 use rustc_middle::hir::nested_filter;
12 use rustc_middle::ty::TyCtxt;
13 use rustc_span::def_id::{CRATE_DEF_ID, LOCAL_CRATE};
14 use rustc_span::symbol::{kw, sym, Symbol};
19 use crate::clean::{cfg::Cfg, AttributesExt, NestedAttributesExt};
22 /// This module is used to store stuff from Rust's AST in a more convenient
23 /// manner (and with prettier names) before cleaning.
25 pub(crate) struct Module<'hir> {
26 pub(crate) name: Symbol,
27 pub(crate) where_inner: Span,
28 pub(crate) mods: Vec<Module<'hir>>,
29 pub(crate) id: hir::HirId,
30 // (item, renamed, import_id)
31 pub(crate) items: Vec<(&'hir hir::Item<'hir>, Option<Symbol>, Option<hir::HirId>)>,
32 pub(crate) foreigns: Vec<(&'hir hir::ForeignItem<'hir>, Option<Symbol>)>,
36 pub(crate) fn new(name: Symbol, id: hir::HirId, where_inner: Span) -> Self {
37 Module { name, id, where_inner, mods: Vec::new(), items: Vec::new(), foreigns: Vec::new() }
40 pub(crate) fn where_outer(&self, tcx: TyCtxt<'_>) -> Span {
41 tcx.hir().span(self.id)
45 // FIXME: Should this be replaced with tcx.def_path_str?
46 fn def_id_to_path(tcx: TyCtxt<'_>, did: DefId) -> Vec<Symbol> {
47 let crate_name = tcx.crate_name(did.krate);
48 let relative = tcx.def_path(did).data.into_iter().filter_map(|elem| elem.data.get_opt_name());
49 std::iter::once(crate_name).chain(relative).collect()
52 pub(crate) fn inherits_doc_hidden(tcx: TyCtxt<'_>, mut node: hir::HirId) -> bool {
53 while let Some(id) = tcx.hir().get_enclosing_scope(node) {
55 if tcx.hir().attrs(node).lists(sym::doc).has_word(sym::hidden) {
62 pub(crate) struct RustdocVisitor<'a, 'tcx> {
63 cx: &'a mut core::DocContext<'tcx>,
64 view_item_stack: FxHashSet<hir::HirId>,
66 /// Are the current module and all of its parents public?
67 inside_public_path: bool,
68 exact_paths: FxHashMap<DefId, Vec<Symbol>>,
69 modules: Vec<Module<'tcx>>,
72 impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
73 pub(crate) fn new(cx: &'a mut core::DocContext<'tcx>) -> RustdocVisitor<'a, 'tcx> {
74 // If the root is re-exported, terminate all recursion.
75 let mut stack = FxHashSet::default();
76 stack.insert(hir::CRATE_HIR_ID);
78 cx.tcx.crate_name(LOCAL_CRATE),
80 cx.tcx.hir().root_module().spans.inner_span,
85 view_item_stack: stack,
87 inside_public_path: true,
88 exact_paths: FxHashMap::default(),
93 fn store_path(&mut self, did: DefId) {
94 let tcx = self.cx.tcx;
95 self.exact_paths.entry(did).or_insert_with(|| def_id_to_path(tcx, did));
98 pub(crate) fn visit(mut self) -> Module<'tcx> {
99 let root_module = self.cx.tcx.hir().root_module();
100 self.visit_mod_contents(CRATE_HIR_ID, root_module);
102 let mut top_level_module = self.modules.pop().unwrap();
104 // `#[macro_export] macro_rules!` items are reexported at the top level of the
105 // crate, regardless of where they're defined. We want to document the
106 // top level rexport of the macro, not its original definition, since
107 // the rexport defines the path that a user will actually see. Accordingly,
108 // we add the rexport as an item here, and then skip over the original
109 // definition in `visit_item()` below.
111 // We also skip `#[macro_export] macro_rules!` that have already been inserted,
112 // it can happen if within the same module a `#[macro_export] macro_rules!`
113 // is declared but also a reexport of itself producing two exports of the same
114 // macro in the same module.
115 let mut inserted = FxHashSet::default();
116 for export in self.cx.tcx.module_reexports(CRATE_DEF_ID).unwrap_or(&[]) {
117 if let Res::Def(DefKind::Macro(_), def_id) = export.res &&
118 let Some(local_def_id) = def_id.as_local() &&
119 self.cx.tcx.has_attr(def_id, sym::macro_export) &&
120 inserted.insert(def_id)
122 let item = self.cx.tcx.hir().expect_item(local_def_id);
123 top_level_module.items.push((item, None, None));
127 self.cx.cache.hidden_cfg = self
133 .filter(|attr| attr.has_name(sym::doc))
134 .flat_map(|attr| attr.meta_item_list().into_iter().flatten())
135 .filter(|attr| attr.has_name(sym::cfg_hide))
137 attr.meta_item_list()
141 Cfg::parse(attr.meta_item()?)
142 .map_err(|e| self.cx.sess().diagnostic().span_err(e.span, e.msg))
148 [Cfg::Cfg(sym::test, None), Cfg::Cfg(sym::doc, None), Cfg::Cfg(sym::doctest, None)]
153 self.cx.cache.exact_paths = self.exact_paths;
157 /// This method will go through the given module items in two passes:
158 /// 1. The items which are not glob imports/reexports.
159 /// 2. The glob imports/reexports.
160 fn visit_mod_contents(&mut self, id: hir::HirId, m: &'tcx hir::Mod<'tcx>) {
161 debug!("Going through module {:?}", m);
162 let def_id = self.cx.tcx.hir().local_def_id(id).to_def_id();
163 // Keep track of if there were any private modules in the path.
164 let orig_inside_public_path = self.inside_public_path;
165 self.inside_public_path &= self.cx.tcx.visibility(def_id).is_public();
167 // Reimplementation of `walk_mod` because we need to do it in two passes (explanations in
169 for &i in m.item_ids {
170 let item = self.cx.tcx.hir().item(i);
171 if !matches!(item.kind, hir::ItemKind::Use(_, hir::UseKind::Glob)) {
172 self.visit_item(item);
175 for &i in m.item_ids {
176 let item = self.cx.tcx.hir().item(i);
177 // To match the way import precedence works, visit glob imports last.
178 // Later passes in rustdoc will de-duplicate by name and kind, so if glob-
179 // imported items appear last, then they'll be the ones that get discarded.
180 if matches!(item.kind, hir::ItemKind::Use(_, hir::UseKind::Glob)) {
181 self.visit_item(item);
184 self.inside_public_path = orig_inside_public_path;
187 /// Tries to resolve the target of a `pub use` statement and inlines the
188 /// target if it is defined locally and would not be documented otherwise,
189 /// or when it is specifically requested with `please_inline`.
190 /// (the latter is the case when the import is marked `doc(inline)`)
192 /// Cross-crate inlining occurs later on during crate cleaning
193 /// and follows different rules.
195 /// Returns `true` if the target has been inlined.
196 fn maybe_inline_local(
200 renamed: Option<Symbol>,
204 debug!("maybe_inline_local res: {:?}", res);
206 if self.cx.output_format.is_json() {
210 let tcx = self.cx.tcx;
211 let Some(res_did) = res.opt_def_id() else {
215 let use_attrs = tcx.hir().attrs(id);
216 // Don't inline `doc(hidden)` imports so they can be stripped at a later stage.
217 let is_no_inline = use_attrs.lists(sym::doc).has_word(sym::no_inline)
218 || use_attrs.lists(sym::doc).has_word(sym::hidden);
220 // For cross-crate impl inlining we need to know whether items are
221 // reachable in documentation -- a previously unreachable item can be
222 // made reachable by cross-crate inlining which we're checking here.
223 // (this is done here because we need to know this upfront).
224 if !res_did.is_local() && !is_no_inline {
225 crate::visit_lib::lib_embargo_visit_item(self.cx, res_did);
229 let res_hir_id = match res_did.as_local() {
230 Some(n) => tcx.hir().local_def_id_to_hir_id(n),
231 None => return false,
235 !self.cx.cache.effective_visibilities.is_directly_public(self.cx.tcx, res_did);
236 let is_hidden = inherits_doc_hidden(self.cx.tcx, res_hir_id);
238 // Only inline if requested or if the item would otherwise be stripped.
239 if (!please_inline && !is_private && !is_hidden) || is_no_inline {
243 if !self.view_item_stack.insert(res_hir_id) {
247 let ret = match tcx.hir().get(res_hir_id) {
248 Node::Item(&hir::Item { kind: hir::ItemKind::Mod(ref m), .. }) if glob => {
249 let prev = mem::replace(&mut self.inlining, true);
250 for &i in m.item_ids {
251 let i = self.cx.tcx.hir().item(i);
252 self.visit_item_inner(i, None, Some(id));
254 self.inlining = prev;
257 Node::Item(it) if !glob => {
258 let prev = mem::replace(&mut self.inlining, true);
259 self.visit_item_inner(it, renamed, Some(id));
260 self.inlining = prev;
263 Node::ForeignItem(it) if !glob => {
264 let prev = mem::replace(&mut self.inlining, true);
265 self.visit_foreign_item_inner(it, renamed);
266 self.inlining = prev;
271 self.view_item_stack.remove(&res_hir_id);
276 fn add_to_current_mod(
278 item: &'tcx hir::Item<'_>,
279 renamed: Option<Symbol>,
280 parent_id: Option<hir::HirId>,
282 self.modules.last_mut().unwrap().items.push((item, renamed, parent_id))
287 item: &'tcx hir::Item<'_>,
288 renamed: Option<Symbol>,
289 parent_id: Option<hir::HirId>,
291 debug!("visiting item {:?}", item);
292 let name = renamed.unwrap_or(item.ident.name);
294 let def_id = item.owner_id.to_def_id();
295 let is_pub = self.cx.tcx.visibility(def_id).is_public();
298 self.store_path(item.owner_id.to_def_id());
302 hir::ItemKind::ForeignMod { items, .. } => {
304 let item = self.cx.tcx.hir().foreign_item(item.id);
305 self.visit_foreign_item_inner(item, None);
308 // If we're inlining, skip private items or item reexported as "_".
309 _ if self.inlining && (!is_pub || renamed == Some(kw::Underscore)) => {}
310 hir::ItemKind::GlobalAsm(..) => {}
311 hir::ItemKind::Use(_, hir::UseKind::ListStem) => {}
312 hir::ItemKind::Use(path, kind) => {
313 for &res in &path.res {
314 // Struct and variant constructors and proc macro stubs always show up alongside
315 // their definitions, we've already processed them so just discard these.
316 if let Res::Def(DefKind::Ctor(..), _) | Res::SelfCtor(..) = res {
320 let attrs = self.cx.tcx.hir().attrs(item.hir_id());
322 // If there was a private module in the current path then don't bother inlining
323 // anything as it will probably be stripped anyway.
324 if is_pub && self.inside_public_path {
325 let please_inline = attrs.iter().any(|item| match item.meta_item_list() {
326 Some(ref list) if item.has_name(sym::doc) => {
327 list.iter().any(|i| i.has_name(sym::inline))
331 let is_glob = kind == hir::UseKind::Glob;
332 let ident = if is_glob { None } else { Some(name) };
333 if self.maybe_inline_local(
344 self.add_to_current_mod(item, renamed, parent_id);
347 hir::ItemKind::Macro(ref macro_def, _) => {
348 // `#[macro_export] macro_rules!` items are handled separately in `visit()`,
349 // above, since they need to be documented at the module top level. Accordingly,
350 // we only want to handle macros if one of three conditions holds:
352 // 1. This macro was defined by `macro`, and thus isn't covered by the case
354 // 2. This macro isn't marked with `#[macro_export]`, and thus isn't covered
355 // by the case above.
356 // 3. We're inlining, since a reexport where inlining has been requested
357 // should be inlined even if it is also documented at the top level.
359 let def_id = item.owner_id.to_def_id();
360 let is_macro_2_0 = !macro_def.macro_rules;
361 let nonexported = !self.cx.tcx.has_attr(def_id, sym::macro_export);
363 if is_macro_2_0 || nonexported || self.inlining {
364 self.add_to_current_mod(item, renamed, None);
367 hir::ItemKind::Mod(ref m) => {
368 self.enter_mod(item.hir_id(), m, name);
370 hir::ItemKind::Fn(..)
371 | hir::ItemKind::ExternCrate(..)
372 | hir::ItemKind::Enum(..)
373 | hir::ItemKind::Struct(..)
374 | hir::ItemKind::Union(..)
375 | hir::ItemKind::TyAlias(..)
376 | hir::ItemKind::OpaqueTy(..)
377 | hir::ItemKind::Static(..)
378 | hir::ItemKind::Trait(..)
379 | hir::ItemKind::TraitAlias(..) => {
380 self.add_to_current_mod(item, renamed, parent_id);
382 hir::ItemKind::Const(..) => {
383 // Underscore constants do not correspond to a nameable item and
384 // so are never useful in documentation.
385 if name != kw::Underscore {
386 self.add_to_current_mod(item, renamed, parent_id);
389 hir::ItemKind::Impl(impl_) => {
390 // Don't duplicate impls when inlining or if it's implementing a trait, we'll pick
391 // them up regardless of where they're located.
392 if !self.inlining && impl_.of_trait.is_none() {
393 self.add_to_current_mod(item, None, None);
400 fn visit_foreign_item_inner(
402 item: &'tcx hir::ForeignItem<'_>,
403 renamed: Option<Symbol>,
405 // If inlining we only want to include public functions.
406 if !self.inlining || self.cx.tcx.visibility(item.owner_id).is_public() {
407 self.modules.last_mut().unwrap().foreigns.push((item, renamed));
411 /// This method will create a new module and push it onto the "modules stack" then call
412 /// `visit_mod_contents`. Once done, it'll remove it from the "modules stack" and instead
413 /// add into into the list of modules of the current module.
414 fn enter_mod(&mut self, id: hir::HirId, m: &'tcx hir::Mod<'tcx>, name: Symbol) {
415 self.modules.push(Module::new(name, id, m.spans.inner_span));
417 self.visit_mod_contents(id, m);
419 let last = self.modules.pop().unwrap();
420 self.modules.last_mut().unwrap().mods.push(last);
424 // We need to implement this visitor so it'll go everywhere and retrieve items we're interested in
425 // such as impl blocks in const blocks.
426 impl<'a, 'tcx> Visitor<'tcx> for RustdocVisitor<'a, 'tcx> {
427 type NestedFilter = nested_filter::All;
429 fn nested_visit_map(&mut self) -> Self::Map {
433 fn visit_item(&mut self, i: &'tcx hir::Item<'tcx>) {
434 let parent_id = if self.modules.len() > 1 {
435 Some(self.modules[self.modules.len() - 2].id)
439 if self.visit_item_inner(i, None, parent_id) {
444 fn visit_mod(&mut self, _: &hir::Mod<'tcx>, _: Span, _: hir::HirId) {
445 // Handled in `visit_item_inner`
448 fn visit_use(&mut self, _: &hir::UsePath<'tcx>, _: hir::HirId) {
449 // Handled in `visit_item_inner`
452 fn visit_path(&mut self, _: &hir::Path<'tcx>, _: hir::HirId) {
453 // Handled in `visit_item_inner`
456 fn visit_label(&mut self, _: &rustc_ast::Label) {
460 fn visit_infer(&mut self, _: &hir::InferArg) {
464 fn visit_lifetime(&mut self, _: &hir::Lifetime) {