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::map::Map;
12 use rustc_middle::hir::nested_filter;
13 use rustc_middle::ty::TyCtxt;
14 use rustc_span::def_id::{CRATE_DEF_ID, LOCAL_CRATE};
15 use rustc_span::symbol::{kw, sym, Symbol};
20 use crate::clean::{cfg::Cfg, AttributesExt, NestedAttributesExt};
23 /// This module is used to store stuff from Rust's AST in a more convenient
24 /// manner (and with prettier names) before cleaning.
26 pub(crate) struct Module<'hir> {
27 pub(crate) name: Symbol,
28 pub(crate) where_inner: Span,
29 pub(crate) mods: Vec<Module<'hir>>,
30 pub(crate) id: hir::HirId,
31 // (item, renamed, import_id)
32 pub(crate) items: Vec<(&'hir hir::Item<'hir>, Option<Symbol>, Option<hir::HirId>)>,
33 pub(crate) foreigns: Vec<(&'hir hir::ForeignItem<'hir>, Option<Symbol>)>,
37 pub(crate) fn new(name: Symbol, id: hir::HirId, where_inner: Span) -> Self {
38 Module { name, id, where_inner, mods: Vec::new(), items: Vec::new(), foreigns: Vec::new() }
41 pub(crate) fn where_outer(&self, tcx: TyCtxt<'_>) -> Span {
42 tcx.hir().span(self.id)
46 // FIXME: Should this be replaced with tcx.def_path_str?
47 fn def_id_to_path(tcx: TyCtxt<'_>, did: DefId) -> Vec<Symbol> {
48 let crate_name = tcx.crate_name(did.krate);
49 let relative = tcx.def_path(did).data.into_iter().filter_map(|elem| elem.data.get_opt_name());
50 std::iter::once(crate_name).chain(relative).collect()
53 pub(crate) fn inherits_doc_hidden(tcx: TyCtxt<'_>, mut node: hir::HirId) -> bool {
54 while let Some(id) = tcx.hir().get_enclosing_scope(node) {
56 if tcx.hir().attrs(node).lists(sym::doc).has_word(sym::hidden) {
63 pub(crate) struct RustdocVisitor<'a, 'tcx> {
64 cx: &'a mut core::DocContext<'tcx>,
65 view_item_stack: FxHashSet<hir::HirId>,
67 /// Are the current module and all of its parents public?
68 inside_public_path: bool,
69 exact_paths: FxHashMap<DefId, Vec<Symbol>>,
70 modules: Vec<Module<'tcx>>,
74 impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
75 pub(crate) fn new(cx: &'a mut core::DocContext<'tcx>) -> RustdocVisitor<'a, 'tcx> {
76 // If the root is re-exported, terminate all recursion.
77 let mut stack = FxHashSet::default();
78 stack.insert(hir::CRATE_HIR_ID);
80 cx.tcx.crate_name(LOCAL_CRATE),
82 cx.tcx.hir().root_module().spans.inner_span,
84 let map = cx.tcx.hir();
88 view_item_stack: stack,
90 inside_public_path: true,
91 exact_paths: FxHashMap::default(),
97 fn store_path(&mut self, did: DefId) {
98 let tcx = self.cx.tcx;
99 self.exact_paths.entry(did).or_insert_with(|| def_id_to_path(tcx, did));
102 /// Tries to resolve the target of a `pub use` statement and inlines the
103 /// target if it is defined locally and would not be documented otherwise,
104 /// or when it is specifically requested with `please_inline`.
105 /// (the latter is the case when the import is marked `doc(inline)`)
107 /// Cross-crate inlining occurs later on during crate cleaning
108 /// and follows different rules.
110 /// Returns `true` if the target has been inlined.
111 fn maybe_inline_local(
115 renamed: Option<Symbol>,
119 debug!("maybe_inline_local res: {:?}", res);
121 if self.cx.output_format.is_json() {
125 let tcx = self.cx.tcx;
126 let Some(res_did) = res.opt_def_id() else {
130 let use_attrs = tcx.hir().attrs(id);
131 // Don't inline `doc(hidden)` imports so they can be stripped at a later stage.
132 let is_no_inline = use_attrs.lists(sym::doc).has_word(sym::no_inline)
133 || use_attrs.lists(sym::doc).has_word(sym::hidden);
135 // For cross-crate impl inlining we need to know whether items are
136 // reachable in documentation -- a previously unreachable item can be
137 // made reachable by cross-crate inlining which we're checking here.
138 // (this is done here because we need to know this upfront).
139 if !res_did.is_local() && !is_no_inline {
140 crate::visit_lib::lib_embargo_visit_item(self.cx, res_did);
144 let res_hir_id = match res_did.as_local() {
145 Some(n) => tcx.hir().local_def_id_to_hir_id(n),
146 None => return false,
150 !self.cx.cache.effective_visibilities.is_directly_public(self.cx.tcx, res_did);
151 let is_hidden = inherits_doc_hidden(self.cx.tcx, res_hir_id);
153 // Only inline if requested or if the item would otherwise be stripped.
154 if (!please_inline && !is_private && !is_hidden) || is_no_inline {
158 if !self.view_item_stack.insert(res_hir_id) {
162 let ret = match tcx.hir().get(res_hir_id) {
163 Node::Item(&hir::Item { kind: hir::ItemKind::Mod(ref m), .. }) if glob => {
164 let prev = mem::replace(&mut self.inlining, true);
165 for &i in m.item_ids {
166 let i = self.cx.tcx.hir().item(i);
167 self.visit_item_inner(i, None, Some(id));
169 self.inlining = prev;
172 Node::Item(it) if !glob => {
173 let prev = mem::replace(&mut self.inlining, true);
174 self.visit_item_inner(it, renamed, Some(id));
175 self.inlining = prev;
178 Node::ForeignItem(it) if !glob => {
179 let prev = mem::replace(&mut self.inlining, true);
180 self.visit_foreign_item_inner(it, renamed);
181 self.inlining = prev;
186 self.view_item_stack.remove(&res_hir_id);
192 item: &'tcx hir::Item<'_>,
193 renamed: Option<Symbol>,
194 parent_id: Option<hir::HirId>,
196 debug!("visiting item {:?}", item);
197 let name = renamed.unwrap_or(item.ident.name);
199 let def_id = item.owner_id.to_def_id();
200 let is_pub = self.cx.tcx.visibility(def_id).is_public();
203 self.store_path(item.owner_id.to_def_id());
207 hir::ItemKind::ForeignMod { items, .. } => {
209 let item = self.cx.tcx.hir().foreign_item(item.id);
210 self.visit_foreign_item_inner(item, None);
213 // If we're inlining, skip private items or item reexported as "_".
214 _ if self.inlining && (!is_pub || renamed == Some(kw::Underscore)) => {}
215 hir::ItemKind::GlobalAsm(..) => {}
216 hir::ItemKind::Use(_, hir::UseKind::ListStem) => {}
217 hir::ItemKind::Use(path, kind) => {
218 for &res in &path.res {
219 // Struct and variant constructors and proc macro stubs always show up alongside
220 // their definitions, we've already processed them so just discard these.
221 if let Res::Def(DefKind::Ctor(..), _) | Res::SelfCtor(..) = res {
225 let attrs = self.cx.tcx.hir().attrs(item.hir_id());
227 // If there was a private module in the current path then don't bother inlining
228 // anything as it will probably be stripped anyway.
229 if is_pub && self.inside_public_path {
230 let please_inline = attrs.iter().any(|item| match item.meta_item_list() {
231 Some(ref list) if item.has_name(sym::doc) => {
232 list.iter().any(|i| i.has_name(sym::inline))
236 let is_glob = kind == hir::UseKind::Glob;
237 let ident = if is_glob { None } else { Some(name) };
238 if self.maybe_inline_local(
250 self.modules.last_mut().unwrap().items.push((item, renamed, parent_id));
253 hir::ItemKind::Macro(ref macro_def, _) => {
254 // `#[macro_export] macro_rules!` items are handled separately in `visit()`,
255 // above, since they need to be documented at the module top level. Accordingly,
256 // we only want to handle macros if one of three conditions holds:
258 // 1. This macro was defined by `macro`, and thus isn't covered by the case
260 // 2. This macro isn't marked with `#[macro_export]`, and thus isn't covered
261 // by the case above.
262 // 3. We're inlining, since a reexport where inlining has been requested
263 // should be inlined even if it is also documented at the top level.
265 let def_id = item.owner_id.to_def_id();
266 let is_macro_2_0 = !macro_def.macro_rules;
267 let nonexported = !self.cx.tcx.has_attr(def_id, sym::macro_export);
269 if is_macro_2_0 || nonexported || self.inlining {
270 self.modules.last_mut().unwrap().items.push((item, renamed, None));
273 hir::ItemKind::Mod(ref m) => {
274 self.enter_mod(item.hir_id(), m, name);
276 hir::ItemKind::Fn(..)
277 | hir::ItemKind::ExternCrate(..)
278 | hir::ItemKind::Enum(..)
279 | hir::ItemKind::Struct(..)
280 | hir::ItemKind::Union(..)
281 | hir::ItemKind::TyAlias(..)
282 | hir::ItemKind::OpaqueTy(..)
283 | hir::ItemKind::Static(..)
284 | hir::ItemKind::Trait(..)
285 | hir::ItemKind::TraitAlias(..) => {
286 self.modules.last_mut().unwrap().items.push((item, renamed, parent_id))
288 hir::ItemKind::Const(..) => {
289 // Underscore constants do not correspond to a nameable item and
290 // so are never useful in documentation.
291 if name != kw::Underscore {
292 self.modules.last_mut().unwrap().items.push((item, renamed, parent_id));
295 hir::ItemKind::Impl(impl_) => {
296 // Don't duplicate impls when inlining or if it's implementing a trait, we'll pick
297 // them up regardless of where they're located.
298 if !self.inlining && impl_.of_trait.is_none() {
299 self.modules.last_mut().unwrap().items.push((item, None, None));
306 fn visit_foreign_item_inner(
308 item: &'tcx hir::ForeignItem<'_>,
309 renamed: Option<Symbol>,
311 // If inlining we only want to include public functions.
312 if !self.inlining || self.cx.tcx.visibility(item.owner_id).is_public() {
313 self.modules.last_mut().unwrap().foreigns.push((item, renamed));
317 pub(crate) fn visit(mut self) -> Module<'tcx> {
318 let root_module = self.cx.tcx.hir().root_module();
319 self.visit_mod_contents(CRATE_HIR_ID, root_module);
321 let mut top_level_module = self.modules.pop().unwrap();
323 // `#[macro_export] macro_rules!` items are reexported at the top level of the
324 // crate, regardless of where they're defined. We want to document the
325 // top level rexport of the macro, not its original definition, since
326 // the rexport defines the path that a user will actually see. Accordingly,
327 // we add the rexport as an item here, and then skip over the original
328 // definition in `visit_item()` below.
330 // We also skip `#[macro_export] macro_rules!` that have already been inserted,
331 // it can happen if within the same module a `#[macro_export] macro_rules!`
332 // is declared but also a reexport of itself producing two exports of the same
333 // macro in the same module.
334 let mut inserted = FxHashSet::default();
335 for export in self.cx.tcx.module_reexports(CRATE_DEF_ID).unwrap_or(&[]) {
336 if let Res::Def(DefKind::Macro(_), def_id) = export.res {
337 if let Some(local_def_id) = def_id.as_local() {
338 if self.cx.tcx.has_attr(def_id, sym::macro_export) {
339 if inserted.insert(def_id) {
340 let item = self.cx.tcx.hir().expect_item(local_def_id);
341 top_level_module.items.push((item, None, None));
348 self.cx.cache.hidden_cfg = self
354 .filter(|attr| attr.has_name(sym::doc))
355 .flat_map(|attr| attr.meta_item_list().into_iter().flatten())
356 .filter(|attr| attr.has_name(sym::cfg_hide))
358 attr.meta_item_list()
362 Cfg::parse(attr.meta_item()?)
363 .map_err(|e| self.cx.sess().diagnostic().span_err(e.span, e.msg))
369 [Cfg::Cfg(sym::test, None), Cfg::Cfg(sym::doc, None), Cfg::Cfg(sym::doctest, None)]
374 self.cx.cache.exact_paths = self.exact_paths;
378 /// This method will create a new module and push it onto the "modules stack" then call
379 /// `visit_mod_contents`. Once done, it'll remove it from the "modules stack" and instead
380 /// add into into the list of modules of the current module.
381 fn enter_mod(&mut self, id: hir::HirId, m: &'tcx hir::Mod<'tcx>, name: Symbol) {
382 self.modules.push(Module::new(name, id, m.spans.inner_span));
384 self.visit_mod_contents(id, m);
386 let last = self.modules.pop().unwrap();
387 self.modules.last_mut().unwrap().mods.push(last);
390 /// This method will go through the given module items in two passes:
391 /// 1. The items which are not glob imports/reexports.
392 /// 2. The glob imports/reexports.
393 fn visit_mod_contents(&mut self, id: hir::HirId, m: &'tcx hir::Mod<'tcx>) {
394 debug!("Going through module {:?}", m);
395 let def_id = self.cx.tcx.hir().local_def_id(id).to_def_id();
396 // Keep track of if there were any private modules in the path.
397 let orig_inside_public_path = self.inside_public_path;
398 self.inside_public_path &= self.cx.tcx.visibility(def_id).is_public();
400 // Reimplementation of `walk_mod`:
401 for &i in m.item_ids {
402 let item = self.cx.tcx.hir().item(i);
403 if !matches!(item.kind, hir::ItemKind::Use(_, hir::UseKind::Glob)) {
404 self.visit_item(item);
407 for &i in m.item_ids {
408 let item = self.cx.tcx.hir().item(i);
409 // To match the way import precedence works, visit glob imports last.
410 // Later passes in rustdoc will de-duplicate by name and kind, so if glob-
411 // imported items appear last, then they'll be the ones that get discarded.
412 if matches!(item.kind, hir::ItemKind::Use(_, hir::UseKind::Glob)) {
413 self.visit_item(item);
416 self.inside_public_path = orig_inside_public_path;
420 // We need to implement this visitor so it'll go everywhere and retrieve items we're interested in
421 // such as impl blocks in const blocks.
422 impl<'a, 'tcx> Visitor<'tcx> for RustdocVisitor<'a, 'tcx> {
423 type NestedFilter = nested_filter::All;
425 fn nested_visit_map(&mut self) -> Self::Map {
429 fn visit_item(&mut self, i: &'tcx hir::Item<'tcx>) {
430 let parent_id = if self.modules.len() > 1 {
431 Some(self.modules[self.modules.len() - 2].id)
435 if self.visit_item_inner(i, None, parent_id) {
440 fn visit_mod(&mut self, _: &hir::Mod<'tcx>, _: Span, _: hir::HirId) {
441 // handled in `visit_item_inner`