src/librustdoc/passes/collect_intra_doc_links.rs

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