src/librustdoc/passes/collect_intra_doc_links.rs

   1 use rustc_ast::ast;
   2 use rustc_errors::Applicability;
   3 use rustc_expand::base::SyntaxExtensionKind;
   4 use rustc_feature::UnstableFeatures;
   5 use rustc_hir as hir;
   6 use rustc_hir::def::{
   7     DefKind,
   8     Namespace::{self, *},
   9     PerNS, Res,
  10 };
  11 use rustc_hir::def_id::DefId;
  12 use rustc_middle::ty;
  13 use rustc_resolve::ParentScope;
  14 use rustc_session::lint;
  15 use rustc_span::hygiene::MacroKind;
  16 use rustc_span::symbol::Ident;
  17 use rustc_span::symbol::Symbol;
  18 use rustc_span::DUMMY_SP;
  19
  20 use std::ops::Range;
  21
  22 use crate::clean::*;
  23 use crate::core::DocContext;
  24 use crate::fold::DocFolder;
  25 use crate::html::markdown::markdown_links;
  26 use crate::passes::{look_for_tests, Pass};
  27
  28 use super::span_of_attrs;
  29
  30 pub const COLLECT_INTRA_DOC_LINKS: Pass = Pass {
  31     name: "collect-intra-doc-links",
  32     run: collect_intra_doc_links,
  33     description: "reads a crate's documentation to resolve intra-doc-links",
  34 };
  35
  36 pub fn collect_intra_doc_links(krate: Crate, cx: &DocContext<'_>) -> Crate {
  37     if !UnstableFeatures::from_environment().is_nightly_build() {
  38         krate
  39     } else {
  40         let mut coll = LinkCollector::new(cx);
  41
  42         coll.fold_crate(krate)
  43     }
  44 }
  45
  46 enum ErrorKind {
  47     ResolutionFailure,
  48     AnchorFailure(&'static str),
  49 }
  50
  51 struct LinkCollector<'a, 'tcx> {
  52     cx: &'a DocContext<'tcx>,
  53     // NOTE: this may not necessarily be a module in the current crate
  54     mod_ids: Vec<DefId>,
  55 }
  56
  57 impl<'a, 'tcx> LinkCollector<'a, 'tcx> {
  58     fn new(cx: &'a DocContext<'tcx>) -> Self {
  59         LinkCollector { cx, mod_ids: Vec::new() }
  60     }
  61
  62     fn variant_field(
  63         &self,
  64         path_str: &str,
  65         current_item: &Option<String>,
  66         module_id: DefId,
  67     ) -> Result<(Res, Option<String>), ErrorKind> {
  68         let cx = self.cx;
  69
  70         let mut split = path_str.rsplitn(3, "::");
  71         let variant_field_name =
  72             split.next().map(|f| Symbol::intern(f)).ok_or(ErrorKind::ResolutionFailure)?;
  73         let variant_name =
  74             split.next().map(|f| Symbol::intern(f)).ok_or(ErrorKind::ResolutionFailure)?;
  75         let path = split
  76             .next()
  77             .map(|f| {
  78                 if f == "self" || f == "Self" {
  79                     if let Some(name) = current_item.as_ref() {
  80                         return name.clone();
  81                     }
  82                 }
  83                 f.to_owned()
  84             })
  85             .ok_or(ErrorKind::ResolutionFailure)?;
  86         let (_, ty_res) = cx
  87             .enter_resolver(|resolver| {
  88                 resolver.resolve_str_path_error(DUMMY_SP, &path, TypeNS, module_id)
  89             })
  90             .map_err(|_| ErrorKind::ResolutionFailure)?;
  91         if let Res::Err = ty_res {
  92             return Err(ErrorKind::ResolutionFailure);
  93         }
  94         let ty_res = ty_res.map_id(|_| panic!("unexpected node_id"));
  95         match ty_res {
  96             Res::Def(DefKind::Enum, did) => {
  97                 if cx
  98                     .tcx
  99                     .inherent_impls(did)
 100                     .iter()
 101                     .flat_map(|imp| cx.tcx.associated_items(*imp).in_definition_order())
 102                     .any(|item| item.ident.name == variant_name)
 103                 {
 104                     return Err(ErrorKind::ResolutionFailure);
 105                 }
 106                 match cx.tcx.type_of(did).kind {
 107                     ty::Adt(def, _) if def.is_enum() => {
 108                         if def.all_fields().any(|item| item.ident.name == variant_field_name) {
 109                             Ok((
 110                                 ty_res,
 111                                 Some(format!(
 112                                     "variant.{}.field.{}",
 113                                     variant_name, variant_field_name
 114                                 )),
 115                             ))
 116                         } else {
 117                             Err(ErrorKind::ResolutionFailure)
 118                         }
 119                     }
 120                     _ => Err(ErrorKind::ResolutionFailure),
 121                 }
 122             }
 123             _ => Err(ErrorKind::ResolutionFailure),
 124         }
 125     }
 126
 127     /// Resolves a string as a macro.
 128     fn macro_resolve(&self, path_str: &str, parent_id: Option<DefId>) -> Option<Res> {
 129         let cx = self.cx;
 130         let path = ast::Path::from_ident(Ident::from_str(path_str));
 131         cx.enter_resolver(|resolver| {
 132             if let Ok((Some(ext), res)) = resolver.resolve_macro_path(
 133                 &path,
 134                 None,
 135                 &ParentScope::module(resolver.graph_root()),
 136                 false,
 137                 false,
 138             ) {
 139                 if let SyntaxExtensionKind::LegacyBang { .. } = ext.kind {
 140                     return Some(res.map_id(|_| panic!("unexpected id")));
 141                 }
 142             }
 143             if let Some(res) = resolver.all_macros().get(&Symbol::intern(path_str)) {
 144                 return Some(res.map_id(|_| panic!("unexpected id")));
 145             }
 146             if let Some(module_id) = parent_id {
 147                 if let Ok((_, res)) =
 148                     resolver.resolve_str_path_error(DUMMY_SP, path_str, MacroNS, module_id)
 149                 {
 150                     // don't resolve builtins like `#[derive]`
 151                     if let Res::Def(..) = res {
 152                         let res = res.map_id(|_| panic!("unexpected node_id"));
 153                         return Some(res);
 154                     }
 155                 }
 156             } else {
 157                 debug!("attempting to resolve item without parent module: {}", path_str);
 158             }
 159             None
 160         })
 161     }
 162     /// Resolves a string as a path within a particular namespace. Also returns an optional
 163     /// URL fragment in the case of variants and methods.
 164     fn resolve(
 165         &self,
 166         path_str: &str,
 167         disambiguator: Option<&str>,
 168         ns: Namespace,
 169         current_item: &Option<String>,
 170         parent_id: Option<DefId>,
 171         extra_fragment: &Option<String>,
 172         item_opt: Option<&Item>,
 173     ) -> Result<(Res, Option<String>), ErrorKind> {
 174         let cx = self.cx;
 175
 176         // In case we're in a module, try to resolve the relative path.
 177         if let Some(module_id) = parent_id {
 178             let result = cx.enter_resolver(|resolver| {
 179                 resolver.resolve_str_path_error(DUMMY_SP, &path_str, ns, module_id)
 180             });
 181             debug!("{} resolved to {:?} in namespace {:?}", path_str, result, ns);
 182             let result = match result {
 183                 Ok((_, Res::Err)) => Err(ErrorKind::ResolutionFailure),
 184                 _ => result.map_err(|_| ErrorKind::ResolutionFailure),
 185             };
 186
 187             if let Ok((_, res)) = result {
 188                 let res = res.map_id(|_| panic!("unexpected node_id"));
 189                 // In case this is a trait item, skip the
 190                 // early return and try looking for the trait.
 191                 let value = match res {
 192                     Res::Def(DefKind::AssocFn | DefKind::AssocConst, _) => true,
 193                     Res::Def(DefKind::AssocTy, _) => false,
 194                     Res::Def(DefKind::Variant, _) => {
 195                         return handle_variant(cx, res, extra_fragment);
 196                     }
 197                     // Not a trait item; just return what we found.
 198                     Res::PrimTy(..) => {
 199                         if extra_fragment.is_some() {
 200                             return Err(ErrorKind::AnchorFailure(
 201                                 "primitive types cannot be followed by anchors",
 202                             ));
 203                         }
 204                         return Ok((res, Some(path_str.to_owned())));
 205                     }
 206                     Res::Def(DefKind::Mod, _) => {
 207                         // This resolved to a module, but if we were passed `type@`,
 208                         // we want primitive types to take precedence instead.
 209                         if disambiguator == Some("type") {
 210                             if let Some(prim) = is_primitive(path_str, ns) {
 211                                 if extra_fragment.is_some() {
 212                                     return Err(ErrorKind::AnchorFailure(
 213                                         "primitive types cannot be followed by anchors",
 214                                     ));
 215                                 }
 216                                 return Ok((prim, Some(path_str.to_owned())));
 217                             }
 218                         }
 219                         return Ok((res, extra_fragment.clone()));
 220                     }
 221                     _ => {
 222                         return Ok((res, extra_fragment.clone()));
 223                     }
 224                 };
 225
 226                 if value != (ns == ValueNS) {
 227                     return Err(ErrorKind::ResolutionFailure);
 228                 }
 229             } else if let Some(prim) = is_primitive(path_str, ns) {
 230                 if extra_fragment.is_some() {
 231                     return Err(ErrorKind::AnchorFailure(
 232                         "primitive types cannot be followed by anchors",
 233                     ));
 234                 }
 235                 return Ok((prim, Some(path_str.to_owned())));
 236             } else {
 237                 // If resolution failed, it may still be a method
 238                 // because methods are not handled by the resolver
 239                 // If so, bail when we're not looking for a value.
 240                 if ns != ValueNS {
 241                     return Err(ErrorKind::ResolutionFailure);
 242                 }
 243             }
 244
 245             // Try looking for methods and associated items.
 246             let mut split = path_str.rsplitn(2, "::");
 247             let item_name =
 248                 split.next().map(|f| Symbol::intern(f)).ok_or(ErrorKind::ResolutionFailure)?;
 249             let path = split
 250                 .next()
 251                 .map(|f| {
 252                     if f == "self" || f == "Self" {
 253                         if let Some(name) = current_item.as_ref() {
 254                             return name.clone();
 255                         }
 256                     }
 257                     f.to_owned()
 258                 })
 259                 .ok_or(ErrorKind::ResolutionFailure)?;
 260
 261             if let Some(prim) = is_primitive(&path, TypeNS) {
 262                 let did = primitive_impl(cx, &path).ok_or(ErrorKind::ResolutionFailure)?;
 263                 return cx
 264                     .tcx
 265                     .associated_items(did)
 266                     .filter_by_name_unhygienic(item_name)
 267                     .next()
 268                     .and_then(|item| match item.kind {
 269                         ty::AssocKind::Fn => Some("method"),
 270                         _ => None,
 271                     })
 272                     .map(|out| (prim, Some(format!("{}#{}.{}", path, out, item_name))))
 273                     .ok_or(ErrorKind::ResolutionFailure);
 274             }
 275
 276             let (_, ty_res) = cx
 277                 .enter_resolver(|resolver| {
 278                     resolver.resolve_str_path_error(DUMMY_SP, &path, TypeNS, module_id)
 279                 })
 280                 .map_err(|_| ErrorKind::ResolutionFailure)?;
 281             if let Res::Err = ty_res {
 282                 return self.variant_field(path_str, current_item, module_id);
 283             }
 284             let ty_res = ty_res.map_id(|_| panic!("unexpected node_id"));
 285             match ty_res {
 286                 Res::Def(
 287                     DefKind::Struct | DefKind::Union | DefKind::Enum | DefKind::TyAlias,
 288                     did,
 289                 ) => {
 290                     // Checks if item_name belongs to `impl SomeItem`
 291                     let impl_item = cx
 292                         .tcx
 293                         .inherent_impls(did)
 294                         .iter()
 295                         .flat_map(|imp| cx.tcx.associated_items(*imp).in_definition_order())
 296                         .find(|item| item.ident.name == item_name);
 297                     let trait_item = item_opt
 298                         .and_then(|item| self.cx.as_local_hir_id(item.def_id))
 299                         .and_then(|item_hir| {
 300                             // Checks if item_name belongs to `impl SomeTrait for SomeItem`
 301                             let parent_hir = self.cx.tcx.hir().get_parent_item(item_hir);
 302                             let item_parent = self.cx.tcx.hir().find(parent_hir);
 303                             match item_parent {
 304                                 Some(hir::Node::Item(hir::Item {
 305                                     kind: hir::ItemKind::Impl { of_trait: Some(_), self_ty, .. },
 306                                     ..
 307                                 })) => cx
 308                                     .tcx
 309                                     .associated_item_def_ids(self_ty.hir_id.owner)
 310                                     .iter()
 311                                     .map(|child| {
 312                                         let associated_item = cx.tcx.associated_item(*child);
 313                                         associated_item
 314                                     })
 315                                     .find(|child| child.ident.name == item_name),
 316                                 _ => None,
 317                             }
 318                         });
 319                     let item = match (impl_item, trait_item) {
 320                         (Some(from_impl), Some(_)) => {
 321                             // Although it's ambiguous, return impl version for compat. sake.
 322                             // To handle that properly resolve() would have to support
 323                             // something like
 324                             // [`ambi_fn`](<SomeStruct as SomeTrait>::ambi_fn)
 325                             Some(from_impl)
 326                         }
 327                         (None, Some(from_trait)) => Some(from_trait),
 328                         (Some(from_impl), None) => Some(from_impl),
 329                         _ => None,
 330                     };
 331
 332                     if let Some(item) = item {
 333                         let out = match item.kind {
 334                             ty::AssocKind::Fn if ns == ValueNS => "method",
 335                             ty::AssocKind::Const if ns == ValueNS => "associatedconstant",
 336                             ty::AssocKind::Type if ns == ValueNS => "associatedtype",
 337                             _ => return self.variant_field(path_str, current_item, module_id),
 338                         };
 339                         if extra_fragment.is_some() {
 340                             Err(ErrorKind::AnchorFailure(if item.kind == ty::AssocKind::Fn {
 341                                 "methods cannot be followed by anchors"
 342                             } else {
 343                                 "associated constants cannot be followed by anchors"
 344                             }))
 345                         } else {
 346                             Ok((ty_res, Some(format!("{}.{}", out, item_name))))
 347                         }
 348                     } else {
 349                         match cx.tcx.type_of(did).kind {
 350                             ty::Adt(def, _) => {
 351                                 if let Some(item) = if def.is_enum() {
 352                                     def.all_fields().find(|item| item.ident.name == item_name)
 353                                 } else {
 354                                     def.non_enum_variant()
 355                                         .fields
 356                                         .iter()
 357                                         .find(|item| item.ident.name == item_name)
 358                                 } {
 359                                     if extra_fragment.is_some() {
 360                                         Err(ErrorKind::AnchorFailure(if def.is_enum() {
 361                                             "enum variants cannot be followed by anchors"
 362                                         } else {
 363                                             "struct fields cannot be followed by anchors"
 364                                         }))
 365                                     } else {
 366                                         Ok((
 367                                             ty_res,
 368                                             Some(format!(
 369                                                 "{}.{}",
 370                                                 if def.is_enum() {
 371                                                     "variant"
 372                                                 } else {
 373                                                     "structfield"
 374                                                 },
 375                                                 item.ident
 376                                             )),
 377                                         ))
 378                                     }
 379                                 } else {
 380                                     self.variant_field(path_str, current_item, module_id)
 381                                 }
 382                             }
 383                             _ => self.variant_field(path_str, current_item, module_id),
 384                         }
 385                     }
 386                 }
 387                 Res::Def(DefKind::Trait, did) => {
 388                     let item = cx
 389                         .tcx
 390                         .associated_item_def_ids(did)
 391                         .iter()
 392                         .map(|item| cx.tcx.associated_item(*item))
 393                         .find(|item| item.ident.name == item_name);
 394                     if let Some(item) = item {
 395                         let kind =
 396                             match item.kind {
 397                                 ty::AssocKind::Const if ns == ValueNS => "associatedconstant",
 398                                 ty::AssocKind::Type if ns == TypeNS => "associatedtype",
 399                                 ty::AssocKind::Fn if ns == ValueNS => {
 400                                     if item.defaultness.has_value() { "method" } else { "tymethod" }
 401                                 }
 402                                 _ => return self.variant_field(path_str, current_item, module_id),
 403                             };
 404
 405                         if extra_fragment.is_some() {
 406                             Err(ErrorKind::AnchorFailure(if item.kind == ty::AssocKind::Const {
 407                                 "associated constants cannot be followed by anchors"
 408                             } else if item.kind == ty::AssocKind::Type {
 409                                 "associated types cannot be followed by anchors"
 410                             } else {
 411                                 "methods cannot be followed by anchors"
 412                             }))
 413                         } else {
 414                             Ok((ty_res, Some(format!("{}.{}", kind, item_name))))
 415                         }
 416                     } else {
 417                         self.variant_field(path_str, current_item, module_id)
 418                     }
 419                 }
 420                 _ => self.variant_field(path_str, current_item, module_id),
 421             }
 422         } else {
 423             debug!("attempting to resolve item without parent module: {}", path_str);
 424             Err(ErrorKind::ResolutionFailure)
 425         }
 426     }
 427 }
 428
 429 /// Check for resolve collisions between a trait and its derive
 430 ///
 431 /// These are common and we should just resolve to the trait in that case
 432 fn is_derive_trait_collision<T>(ns: &PerNS<Option<(Res, T)>>) -> bool {
 433     if let PerNS {
 434         type_ns: Some((Res::Def(DefKind::Trait, _), _)),
 435         macro_ns: Some((Res::Def(DefKind::Macro(MacroKind::Derive), _), _)),
 436         ..
 437     } = *ns
 438     {
 439         true
 440     } else {
 441         false
 442     }
 443 }
 444
 445 impl<'a, 'tcx> DocFolder for LinkCollector<'a, 'tcx> {
 446     fn fold_item(&mut self, mut item: Item) -> Option<Item> {
 447         use rustc_middle::ty::DefIdTree;
 448
 449         let parent_node = if item.is_fake() {
 450             // FIXME: is this correct?
 451             None
 452         } else {
 453             let mut current = item.def_id;
 454             // The immediate parent might not always be a module.
 455             // Find the first parent which is.
 456             loop {
 457                 if let Some(parent) = self.cx.tcx.parent(current) {
 458                     if self.cx.tcx.def_kind(parent) == DefKind::Mod {
 459                         break Some(parent);
 460                     }
 461                     current = parent;
 462                 } else {
 463                     break None;
 464                 }
 465             }
 466         };
 467
 468         if parent_node.is_some() {
 469             trace!("got parent node for {:?} {:?}, id {:?}", item.type_(), item.name, item.def_id);
 470         }
 471
 472         let current_item = match item.inner {
 473             ModuleItem(..) => {
 474                 if item.attrs.inner_docs {
 475                     if item.def_id.is_top_level_module() { item.name.clone() } else { None }
 476                 } else {
 477                     match parent_node.or(self.mod_ids.last().copied()) {
 478                         Some(parent) if !parent.is_top_level_module() => {
 479                             // FIXME: can we pull the parent module's name from elsewhere?
 480                             Some(self.cx.tcx.item_name(parent).to_string())
 481                         }
 482                         _ => None,
 483                     }
 484                 }
 485             }
 486             ImplItem(Impl { ref for_, .. }) => {
 487                 for_.def_id().map(|did| self.cx.tcx.item_name(did).to_string())
 488             }
 489             // we don't display docs on `extern crate` items anyway, so don't process them.
 490             ExternCrateItem(..) => {
 491                 debug!("ignoring extern crate item {:?}", item.def_id);
 492                 return self.fold_item_recur(item);
 493             }
 494             ImportItem(Import::Simple(ref name, ..)) => Some(name.clone()),
 495             MacroItem(..) => None,
 496             _ => item.name.clone(),
 497         };
 498
 499         if item.is_mod() && item.attrs.inner_docs {
 500             self.mod_ids.push(item.def_id);
 501         }
 502
 503         let cx = self.cx;
 504         let dox = item.attrs.collapsed_doc_value().unwrap_or_else(String::new);
 505         trace!("got documentation '{}'", dox);
 506
 507         look_for_tests(&cx, &dox, &item, true);
 508
 509         // find item's parent to resolve `Self` in item's docs below
 510         let parent_name = self.cx.as_local_hir_id(item.def_id).and_then(|item_hir| {
 511             let parent_hir = self.cx.tcx.hir().get_parent_item(item_hir);
 512             let item_parent = self.cx.tcx.hir().find(parent_hir);
 513             match item_parent {
 514                 Some(hir::Node::Item(hir::Item {
 515                     kind:
 516                         hir::ItemKind::Impl {
 517                             self_ty:
 518                                 hir::Ty {
 519                                     kind:
 520                                         hir::TyKind::Path(hir::QPath::Resolved(
 521                                             _,
 522                                             hir::Path { segments, .. },
 523                                         )),
 524                                     ..
 525                                 },
 526                             ..
 527                         },
 528                     ..
 529                 })) => segments.first().map(|seg| seg.ident.to_string()),
 530                 Some(hir::Node::Item(hir::Item {
 531                     ident, kind: hir::ItemKind::Enum(..), ..
 532                 }))
 533                 | Some(hir::Node::Item(hir::Item {
 534                     ident, kind: hir::ItemKind::Struct(..), ..
 535                 }))
 536                 | Some(hir::Node::Item(hir::Item {
 537                     ident, kind: hir::ItemKind::Union(..), ..
 538                 }))
 539                 | Some(hir::Node::Item(hir::Item {
 540                     ident, kind: hir::ItemKind::Trait(..), ..
 541                 })) => Some(ident.to_string()),
 542                 _ => None,
 543             }
 544         });
 545
 546         for (ori_link, link_range) in markdown_links(&dox) {
 547             trace!("considering link '{}'", ori_link);
 548
 549             // Bail early for real links.
 550             if ori_link.contains('/') {
 551                 continue;
 552             }
 553
 554             // [] is mostly likely not supposed to be a link
 555             if ori_link.is_empty() {
 556                 continue;
 557             }
 558
 559             let link = ori_link.replace("`", "");
 560             let parts = link.split('#').collect::<Vec<_>>();
 561             let (link, extra_fragment) = if parts.len() > 2 {
 562                 build_diagnostic(
 563                     cx,
 564                     &item,
 565                     &link,
 566                     &dox,
 567                     link_range,
 568                     "has an issue with the link anchor.",
 569                     "only one `#` is allowed in a link",
 570                     None,
 571                 );
 572                 continue;
 573             } else if parts.len() == 2 {
 574                 if parts[0].trim().is_empty() {
 575                     // This is an anchor to an element of the current page, nothing to do in here!
 576                     continue;
 577                 }
 578                 (parts[0].to_owned(), Some(parts[1].to_owned()))
 579             } else {
 580                 (parts[0].to_owned(), None)
 581             };
 582             let resolved_self;
 583             let mut path_str;
 584             let (res, fragment) = {
 585                 let mut kind = None;
 586                 let mut disambiguator = None;
 587                 path_str = if let Some(prefix) =
 588                     ["struct@", "enum@", "type@", "trait@", "union@", "module@", "mod@"]
 589                         .iter()
 590                         .find(|p| link.starts_with(**p))
 591                 {
 592                     kind = Some(TypeNS);
 593                     disambiguator = Some(&prefix[..prefix.len() - 1]);
 594                     link.trim_start_matches(prefix)
 595                 } else if let Some(prefix) =
 596                     ["const@", "static@", "value@", "function@", "fn@", "method@"]
 597                         .iter()
 598                         .find(|p| link.starts_with(**p))
 599                 {
 600                     kind = Some(ValueNS);
 601                     disambiguator = Some(&prefix[..prefix.len() - 1]);
 602                     link.trim_start_matches(prefix)
 603                 } else if link.ends_with("!()") {
 604                     kind = Some(MacroNS);
 605                     link.trim_end_matches("!()")
 606                 } else if link.ends_with("()") {
 607                     kind = Some(ValueNS);
 608                     disambiguator = Some("fn");
 609                     link.trim_end_matches("()")
 610                 } else if link.starts_with("macro@") {
 611                     kind = Some(MacroNS);
 612                     disambiguator = Some("macro");
 613                     link.trim_start_matches("macro@")
 614                 } else if link.starts_with("derive@") {
 615                     kind = Some(MacroNS);
 616                     disambiguator = Some("derive");
 617                     link.trim_start_matches("derive@")
 618                 } else if link.ends_with('!') {
 619                     kind = Some(MacroNS);
 620                     disambiguator = Some("macro");
 621                     link.trim_end_matches('!')
 622                 } else {
 623                     &link[..]
 624                 }
 625                 .trim();
 626
 627                 if path_str.contains(|ch: char| !(ch.is_alphanumeric() || ch == ':' || ch == '_')) {
 628                     continue;
 629                 }
 630
 631                 // In order to correctly resolve intra-doc-links we need to
 632                 // pick a base AST node to work from.  If the documentation for
 633                 // this module came from an inner comment (//!) then we anchor
 634                 // our name resolution *inside* the module.  If, on the other
 635                 // hand it was an outer comment (///) then we anchor the name
 636                 // resolution in the parent module on the basis that the names
 637                 // used are more likely to be intended to be parent names.  For
 638                 // this, we set base_node to None for inner comments since
 639                 // we've already pushed this node onto the resolution stack but
 640                 // for outer comments we explicitly try and resolve against the
 641                 // parent_node first.
 642                 let base_node = if item.is_mod() && item.attrs.inner_docs {
 643                     self.mod_ids.last().copied()
 644                 } else {
 645                     parent_node
 646                 };
 647
 648                 // replace `Self` with suitable item's parent name
 649                 if path_str.starts_with("Self::") {
 650                     if let Some(ref name) = parent_name {
 651                         resolved_self = format!("{}::{}", name, &path_str[6..]);
 652                         path_str = &resolved_self;
 653                     }
 654                 }
 655
 656                 match kind {
 657                     Some(ns @ ValueNS) => {
 658                         match self.resolve(
 659                             path_str,
 660                             disambiguator,
 661                             ns,
 662                             &current_item,
 663                             base_node,
 664                             &extra_fragment,
 665                             Some(&item),
 666                         ) {
 667                             Ok(res) => res,
 668                             Err(ErrorKind::ResolutionFailure) => {
 669                                 resolution_failure(cx, &item, path_str, &dox, link_range);
 670                                 // This could just be a normal link or a broken link
 671                                 // we could potentially check if something is
 672                                 // "intra-doc-link-like" and warn in that case.
 673                                 continue;
 674                             }
 675                             Err(ErrorKind::AnchorFailure(msg)) => {
 676                                 anchor_failure(cx, &item, &ori_link, &dox, link_range, msg);
 677                                 continue;
 678                             }
 679                         }
 680                     }
 681                     Some(ns @ TypeNS) => {
 682                         match self.resolve(
 683                             path_str,
 684                             disambiguator,
 685                             ns,
 686                             &current_item,
 687                             base_node,
 688                             &extra_fragment,
 689                             Some(&item),
 690                         ) {
 691                             Ok(res) => res,
 692                             Err(ErrorKind::ResolutionFailure) => {
 693                                 resolution_failure(cx, &item, path_str, &dox, link_range);
 694                                 // This could just be a normal link.
 695                                 continue;
 696                             }
 697                             Err(ErrorKind::AnchorFailure(msg)) => {
 698                                 anchor_failure(cx, &item, &ori_link, &dox, link_range, msg);
 699                                 continue;
 700                             }
 701                         }
 702                     }
 703                     None => {
 704                         // Try everything!
 705                         let mut candidates = PerNS {
 706                             macro_ns: self
 707                                 .macro_resolve(path_str, base_node)
 708                                 .map(|res| (res, extra_fragment.clone())),
 709                             type_ns: match self.resolve(
 710                                 path_str,
 711                                 disambiguator,
 712                                 TypeNS,
 713                                 &current_item,
 714                                 base_node,
 715                                 &extra_fragment,
 716                                 Some(&item),
 717                             ) {
 718                                 Err(ErrorKind::AnchorFailure(msg)) => {
 719                                     anchor_failure(cx, &item, &ori_link, &dox, link_range, msg);
 720                                     continue;
 721                                 }
 722                                 x => x.ok(),
 723                             },
 724                             value_ns: match self.resolve(
 725                                 path_str,
 726                                 disambiguator,
 727                                 ValueNS,
 728                                 &current_item,
 729                                 base_node,
 730                                 &extra_fragment,
 731                                 Some(&item),
 732                             ) {
 733                                 Err(ErrorKind::AnchorFailure(msg)) => {
 734                                     anchor_failure(cx, &item, &ori_link, &dox, link_range, msg);
 735                                     continue;
 736                                 }
 737                                 x => x.ok(),
 738                             }
 739                             .and_then(|(res, fragment)| {
 740                                 // Constructors are picked up in the type namespace.
 741                                 match res {
 742                                     Res::Def(DefKind::Ctor(..), _) | Res::SelfCtor(..) => None,
 743                                     _ => match (fragment, extra_fragment) {
 744                                         (Some(fragment), Some(_)) => {
 745                                             // Shouldn't happen but who knows?
 746                                             Some((res, Some(fragment)))
 747                                         }
 748                                         (fragment, None) | (None, fragment) => {
 749                                             Some((res, fragment))
 750                                         }
 751                                     },
 752                                 }
 753                             }),
 754                         };
 755
 756                         if candidates.is_empty() {
 757                             resolution_failure(cx, &item, path_str, &dox, link_range);
 758                             // this could just be a normal link
 759                             continue;
 760                         }
 761
 762                         let len = candidates.clone().present_items().count();
 763
 764                         if len == 1 {
 765                             candidates.present_items().next().unwrap()
 766                         } else if len == 2 && is_derive_trait_collision(&candidates) {
 767                             candidates.type_ns.unwrap()
 768                         } else {
 769                             if is_derive_trait_collision(&candidates) {
 770                                 candidates.macro_ns = None;
 771                             }
 772                             ambiguity_error(
 773                                 cx,
 774                                 &item,
 775                                 path_str,
 776                                 &dox,
 777                                 link_range,
 778                                 candidates.map(|candidate| candidate.map(|(res, _)| res)),
 779                             );
 780                             continue;
 781                         }
 782                     }
 783                     Some(MacroNS) => {
 784                         if let Some(res) = self.macro_resolve(path_str, base_node) {
 785                             (res, extra_fragment)
 786                         } else {
 787                             resolution_failure(cx, &item, path_str, &dox, link_range);
 788                             continue;
 789                         }
 790                     }
 791                 }
 792             };
 793
 794             if let Res::PrimTy(_) = res {
 795                 item.attrs.links.push((ori_link, None, fragment));
 796             } else {
 797                 debug!("intra-doc link to {} resolved to {:?}", path_str, res);
 798                 if let Some(local) = res.opt_def_id().and_then(|def_id| def_id.as_local()) {
 799                     use rustc_hir::def_id::LOCAL_CRATE;
 800
 801                     let hir_id = self.cx.tcx.hir().as_local_hir_id(local);
 802                     if !self.cx.tcx.privacy_access_levels(LOCAL_CRATE).is_exported(hir_id)
 803                         && (item.visibility == Visibility::Public)
 804                         && !self.cx.render_options.document_private
 805                     {
 806                         let item_name = item.name.as_deref().unwrap_or("<unknown>");
 807                         let err_msg = format!(
 808                             "public documentation for `{}` links to a private item",
 809                             item_name
 810                         );
 811                         build_diagnostic(
 812                             cx,
 813                             &item,
 814                             path_str,
 815                             &dox,
 816                             link_range,
 817                             &err_msg,
 818                             "this item is private",
 819                             None,
 820                         );
 821                         continue;
 822                     }
 823                 }
 824                 let id = register_res(cx, res);
 825                 item.attrs.links.push((ori_link, Some(id), fragment));
 826             }
 827         }
 828
 829         if item.is_mod() && !item.attrs.inner_docs {
 830             self.mod_ids.push(item.def_id);
 831         }
 832
 833         if item.is_mod() {
 834             let ret = self.fold_item_recur(item);
 835
 836             self.mod_ids.pop();
 837
 838             ret
 839         } else {
 840             self.fold_item_recur(item)
 841         }
 842     }
 843
 844     // FIXME: if we can resolve intra-doc links from other crates, we can use the stock
 845     // `fold_crate`, but until then we should avoid scanning `krate.external_traits` since those
 846     // will never resolve properly
 847     fn fold_crate(&mut self, mut c: Crate) -> Crate {
 848         c.module = c.module.take().and_then(|module| self.fold_item(module));
 849
 850         c
 851     }
 852 }
 853
 854 fn build_diagnostic(
 855     cx: &DocContext<'_>,
 856     item: &Item,
 857     path_str: &str,
 858     dox: &str,
 859     link_range: Option<Range<usize>>,
 860     err_msg: &str,
 861     short_err_msg: &str,
 862     help_msg: Option<&str>,
 863 ) {
 864     let hir_id = match cx.as_local_hir_id(item.def_id) {
 865         Some(hir_id) => hir_id,
 866         None => {
 867             // If non-local, no need to check anything.
 868             info!("ignoring warning from parent crate: {}", err_msg);
 869             return;
 870         }
 871     };
 872     let attrs = &item.attrs;
 873     let sp = span_of_attrs(attrs).unwrap_or(item.source.span());
 874
 875     cx.tcx.struct_span_lint_hir(
 876         lint::builtin::INTRA_DOC_LINK_RESOLUTION_FAILURE,
 877         hir_id,
 878         sp,
 879         |lint| {
 880             let mut diag = lint.build(&format!("`[{}]` {}", path_str, err_msg));
 881             if let Some(link_range) = link_range {
 882                 if let Some(sp) = super::source_span_for_markdown_range(cx, dox, &link_range, attrs)
 883                 {
 884                     diag.set_span(sp);
 885                     diag.span_label(sp, short_err_msg);
 886                 } else {
 887                     // blah blah blah\nblah\nblah [blah] blah blah\nblah blah
 888                     //                       ^     ~~~~
 889                     //                       |     link_range
 890                     //                       last_new_line_offset
 891                     let last_new_line_offset =
 892                         dox[..link_range.start].rfind('\n').map_or(0, |n| n + 1);
 893                     let line = dox[last_new_line_offset..].lines().next().unwrap_or("");
 894
 895                     // Print the line containing the `link_range` and manually mark it with '^'s.
 896                     diag.note(&format!(
 897                         "the link appears in this line:\n\n{line}\n\
 898                          {indicator: <before$}{indicator:^<found$}",
 899                         line = line,
 900                         indicator = "",
 901                         before = link_range.start - last_new_line_offset,
 902                         found = link_range.len(),
 903                     ));
 904                 }
 905             };
 906             if let Some(help_msg) = help_msg {
 907                 diag.help(help_msg);
 908             }
 909             diag.emit();
 910         },
 911     );
 912 }
 913
 914 /// Reports a resolution failure diagnostic.
 915 ///
 916 /// If we cannot find the exact source span of the resolution failure, we use the span of the
 917 /// documentation attributes themselves. This is a little heavy-handed, so we display the markdown
 918 /// line containing the failure as a note as well.
 919 fn resolution_failure(
 920     cx: &DocContext<'_>,
 921     item: &Item,
 922     path_str: &str,
 923     dox: &str,
 924     link_range: Option<Range<usize>>,
 925 ) {
 926     build_diagnostic(
 927         cx,
 928         item,
 929         path_str,
 930         dox,
 931         link_range,
 932         "cannot be resolved, ignoring it.",
 933         "cannot be resolved, ignoring",
 934         Some("to escape `[` and `]` characters, just add '\\' before them like `\\[` or `\\]`"),
 935     );
 936 }
 937
 938 fn anchor_failure(
 939     cx: &DocContext<'_>,
 940     item: &Item,
 941     path_str: &str,
 942     dox: &str,
 943     link_range: Option<Range<usize>>,
 944     msg: &str,
 945 ) {
 946     build_diagnostic(
 947         cx,
 948         item,
 949         path_str,
 950         dox,
 951         link_range,
 952         "has an issue with the link anchor.",
 953         msg,
 954         None,
 955     );
 956 }
 957
 958 fn ambiguity_error(
 959     cx: &DocContext<'_>,
 960     item: &Item,
 961     path_str: &str,
 962     dox: &str,
 963     link_range: Option<Range<usize>>,
 964     candidates: PerNS<Option<Res>>,
 965 ) {
 966     let hir_id = match cx.as_local_hir_id(item.def_id) {
 967         Some(hir_id) => hir_id,
 968         None => {
 969             // If non-local, no need to check anything.
 970             return;
 971         }
 972     };
 973     let attrs = &item.attrs;
 974     let sp = span_of_attrs(attrs).unwrap_or(item.source.span());
 975
 976     cx.tcx.struct_span_lint_hir(
 977         lint::builtin::INTRA_DOC_LINK_RESOLUTION_FAILURE,
 978         hir_id,
 979         sp,
 980         |lint| {
 981             let mut msg = format!("`{}` is ", path_str);
 982
 983             let candidates = [TypeNS, ValueNS, MacroNS]
 984                 .iter()
 985                 .filter_map(|&ns| candidates[ns].map(|res| (res, ns)))
 986                 .collect::<Vec<_>>();
 987             match candidates.as_slice() {
 988                 [(first_def, _), (second_def, _)] => {
 989                     msg += &format!(
 990                         "both {} {} and {} {}",
 991                         first_def.article(),
 992                         first_def.descr(),
 993                         second_def.article(),
 994                         second_def.descr(),
 995                     );
 996                 }
 997                 _ => {
 998                     let mut candidates = candidates.iter().peekable();
 999                     while let Some((res, _)) = candidates.next() {
1000                         if candidates.peek().is_some() {
1001                             msg += &format!("{} {}, ", res.article(), res.descr());
1002                         } else {
1003                             msg += &format!("and {} {}", res.article(), res.descr());
1004                         }
1005                     }
1006                 }
1007             }
1008
1009             let mut diag = lint.build(&msg);
1010
1011             if let Some(link_range) = link_range {
1012                 if let Some(sp) = super::source_span_for_markdown_range(cx, dox, &link_range, attrs)
1013                 {
1014                     diag.set_span(sp);
1015                     diag.span_label(sp, "ambiguous link");
1016
1017                     for (res, ns) in candidates {
1018                         let (action, mut suggestion) = match res {
1019                             Res::Def(DefKind::AssocFn | DefKind::Fn, _) => {
1020                                 ("add parentheses", format!("{}()", path_str))
1021                             }
1022                             Res::Def(DefKind::Macro(MacroKind::Bang), _) => {
1023                                 ("add an exclamation mark", format!("{}!", path_str))
1024                             }
1025                             _ => {
1026                                 let type_ = match (res, ns) {
1027                                     (Res::Def(DefKind::Const, _), _) => "const",
1028                                     (Res::Def(DefKind::Static, _), _) => "static",
1029                                     (Res::Def(DefKind::Struct, _), _) => "struct",
1030                                     (Res::Def(DefKind::Enum, _), _) => "enum",
1031                                     (Res::Def(DefKind::Union, _), _) => "union",
1032                                     (Res::Def(DefKind::Trait, _), _) => "trait",
1033                                     (Res::Def(DefKind::Mod, _), _) => "module",
1034                                     (_, TypeNS) => "type",
1035                                     (_, ValueNS) => "value",
1036                                     (Res::Def(DefKind::Macro(MacroKind::Derive), _), MacroNS) => {
1037                                         "derive"
1038                                     }
1039                                     (_, MacroNS) => "macro",
1040                                 };
1041
1042                                 // FIXME: if this is an implied shortcut link, it's bad style to suggest `@`
1043                                 ("prefix with the item type", format!("{}@{}", type_, path_str))
1044                             }
1045                         };
1046
1047                         if dox.bytes().nth(link_range.start) == Some(b'`') {
1048                             suggestion = format!("`{}`", suggestion);
1049                         }
1050
1051                         diag.span_suggestion(
1052                             sp,
1053                             &format!("to link to the {}, {}", res.descr(), action),
1054                             suggestion,
1055                             Applicability::MaybeIncorrect,
1056                         );
1057                     }
1058                 } else {
1059                     // blah blah blah\nblah\nblah [blah] blah blah\nblah blah
1060                     //                       ^     ~~~~
1061                     //                       |     link_range
1062                     //                       last_new_line_offset
1063                     let last_new_line_offset =
1064                         dox[..link_range.start].rfind('\n').map_or(0, |n| n + 1);
1065                     let line = dox[last_new_line_offset..].lines().next().unwrap_or("");
1066
1067                     // Print the line containing the `link_range` and manually mark it with '^'s.
1068                     diag.note(&format!(
1069                         "the link appears in this line:\n\n{line}\n\
1070                          {indicator: <before$}{indicator:^<found$}",
1071                         line = line,
1072                         indicator = "",
1073                         before = link_range.start - last_new_line_offset,
1074                         found = link_range.len(),
1075                     ));
1076                 }
1077             }
1078             diag.emit();
1079         },
1080     );
1081 }
1082
1083 /// Given an enum variant's res, return the res of its enum and the associated fragment.
1084 fn handle_variant(
1085     cx: &DocContext<'_>,
1086     res: Res,
1087     extra_fragment: &Option<String>,
1088 ) -> Result<(Res, Option<String>), ErrorKind> {
1089     use rustc_middle::ty::DefIdTree;
1090
1091     if extra_fragment.is_some() {
1092         return Err(ErrorKind::AnchorFailure("variants cannot be followed by anchors"));
1093     }
1094     let parent = if let Some(parent) = cx.tcx.parent(res.def_id()) {
1095         parent
1096     } else {
1097         return Err(ErrorKind::ResolutionFailure);
1098     };
1099     let parent_def = Res::Def(DefKind::Enum, parent);
1100     let variant = cx.tcx.expect_variant_res(res);
1101     Ok((parent_def, Some(format!("variant.{}", variant.ident.name))))
1102 }
1103
1104 const PRIMITIVES: &[(&str, Res)] = &[
1105     ("u8", Res::PrimTy(hir::PrimTy::Uint(rustc_ast::ast::UintTy::U8))),
1106     ("u16", Res::PrimTy(hir::PrimTy::Uint(rustc_ast::ast::UintTy::U16))),
1107     ("u32", Res::PrimTy(hir::PrimTy::Uint(rustc_ast::ast::UintTy::U32))),
1108     ("u64", Res::PrimTy(hir::PrimTy::Uint(rustc_ast::ast::UintTy::U64))),
1109     ("u128", Res::PrimTy(hir::PrimTy::Uint(rustc_ast::ast::UintTy::U128))),
1110     ("usize", Res::PrimTy(hir::PrimTy::Uint(rustc_ast::ast::UintTy::Usize))),
1111     ("i8", Res::PrimTy(hir::PrimTy::Int(rustc_ast::ast::IntTy::I8))),
1112     ("i16", Res::PrimTy(hir::PrimTy::Int(rustc_ast::ast::IntTy::I16))),
1113     ("i32", Res::PrimTy(hir::PrimTy::Int(rustc_ast::ast::IntTy::I32))),
1114     ("i64", Res::PrimTy(hir::PrimTy::Int(rustc_ast::ast::IntTy::I64))),
1115     ("i128", Res::PrimTy(hir::PrimTy::Int(rustc_ast::ast::IntTy::I128))),
1116     ("isize", Res::PrimTy(hir::PrimTy::Int(rustc_ast::ast::IntTy::Isize))),
1117     ("f32", Res::PrimTy(hir::PrimTy::Float(rustc_ast::ast::FloatTy::F32))),
1118     ("f64", Res::PrimTy(hir::PrimTy::Float(rustc_ast::ast::FloatTy::F64))),
1119     ("str", Res::PrimTy(hir::PrimTy::Str)),
1120     ("bool", Res::PrimTy(hir::PrimTy::Bool)),
1121     ("char", Res::PrimTy(hir::PrimTy::Char)),
1122 ];
1123
1124 fn is_primitive(path_str: &str, ns: Namespace) -> Option<Res> {
1125     if ns == TypeNS { PRIMITIVES.iter().find(|x| x.0 == path_str).map(|x| x.1) } else { None }
1126 }
1127
1128 fn primitive_impl(cx: &DocContext<'_>, path_str: &str) -> Option<DefId> {
1129     let tcx = cx.tcx;
1130     match path_str {
1131         "u8" => tcx.lang_items().u8_impl(),
1132         "u16" => tcx.lang_items().u16_impl(),
1133         "u32" => tcx.lang_items().u32_impl(),
1134         "u64" => tcx.lang_items().u64_impl(),
1135         "u128" => tcx.lang_items().u128_impl(),
1136         "usize" => tcx.lang_items().usize_impl(),
1137         "i8" => tcx.lang_items().i8_impl(),
1138         "i16" => tcx.lang_items().i16_impl(),
1139         "i32" => tcx.lang_items().i32_impl(),
1140         "i64" => tcx.lang_items().i64_impl(),
1141         "i128" => tcx.lang_items().i128_impl(),
1142         "isize" => tcx.lang_items().isize_impl(),
1143         "f32" => tcx.lang_items().f32_impl(),
1144         "f64" => tcx.lang_items().f64_impl(),
1145         "str" => tcx.lang_items().str_impl(),
1146         "bool" => tcx.lang_items().bool_impl(),
1147         "char" => tcx.lang_items().char_impl(),
1148         _ => None,
1149     }
1150 }