src/librustdoc/passes/collect_intra_doc_links.rs

   1 use errors::Applicability;
   2 use rustc::hir::def::{Res, DefKind, Namespace::{self, *}, PerNS};
   3 use rustc::hir::def_id::DefId;
   4 use rustc::hir;
   5 use rustc::lint as lint;
   6 use rustc::ty;
   7 use rustc_resolve::ParentScope;
   8 use syntax;
   9 use syntax::ast::{self, Ident};
  10 use syntax::ext::base::SyntaxExtensionKind;
  11 use syntax::feature_gate::UnstableFeatures;
  12 use syntax::symbol::Symbol;
  13 use syntax_pos::DUMMY_SP;
  14
  15 use std::ops::Range;
  16
  17 use crate::core::DocContext;
  18 use crate::fold::DocFolder;
  19 use crate::html::markdown::markdown_links;
  20 use crate::clean::*;
  21 use crate::passes::{look_for_tests, Pass};
  22
  23 use super::span_of_attrs;
  24
  25 pub const COLLECT_INTRA_DOC_LINKS: Pass = Pass {
  26     name: "collect-intra-doc-links",
  27     pass: collect_intra_doc_links,
  28     description: "reads a crate's documentation to resolve intra-doc-links",
  29 };
  30
  31 pub fn collect_intra_doc_links(krate: Crate, cx: &DocContext<'_>) -> Crate {
  32     if !UnstableFeatures::from_environment().is_nightly_build() {
  33         krate
  34     } else {
  35         let mut coll = LinkCollector::new(cx);
  36
  37         coll.fold_crate(krate)
  38     }
  39 }
  40
  41 struct LinkCollector<'a, 'tcx> {
  42     cx: &'a DocContext<'tcx>,
  43     mod_ids: Vec<hir::HirId>,
  44 }
  45
  46 impl<'a, 'tcx> LinkCollector<'a, 'tcx> {
  47     fn new(cx: &'a DocContext<'tcx>) -> Self {
  48         LinkCollector {
  49             cx,
  50             mod_ids: Vec::new(),
  51         }
  52     }
  53
  54     /// Resolves a string as a path within a particular namespace. Also returns an optional
  55     /// URL fragment in the case of variants and methods.
  56     fn resolve(&self,
  57                path_str: &str,
  58                ns: Namespace,
  59                current_item: &Option<String>,
  60                parent_id: Option<hir::HirId>)
  61         -> Result<(Res, Option<String>), ()>
  62     {
  63         let cx = self.cx;
  64
  65         // In case we're in a module, try to resolve the relative path.
  66         if let Some(module_id) = parent_id.or(self.mod_ids.last().cloned()) {
  67             let module_id = cx.tcx.hir().hir_to_node_id(module_id);
  68             let result = cx.enter_resolver(|resolver| {
  69                 resolver.resolve_str_path_error(DUMMY_SP, &path_str, ns, module_id)
  70             });
  71             let result = match result {
  72                 Ok((_, Res::Err)) => Err(()),
  73                 _ => result,
  74             };
  75
  76             if let Ok((_, res)) = result {
  77                 let res = res.map_id(|_| panic!("unexpected node_id"));
  78                 // In case this is a trait item, skip the
  79                 // early return and try looking for the trait.
  80                 let value = match res {
  81                     Res::Def(DefKind::Method, _) | Res::Def(DefKind::AssocConst, _) => true,
  82                     Res::Def(DefKind::AssocTy, _) => false,
  83                     Res::Def(DefKind::Variant, _) => return handle_variant(cx, res),
  84                     // Not a trait item; just return what we found.
  85                     Res::PrimTy(..) => return Ok((res, Some(path_str.to_owned()))),
  86                     _ => return Ok((res, None))
  87                 };
  88
  89                 if value != (ns == ValueNS) {
  90                     return Err(())
  91                 }
  92             } else if let Some(prim) = is_primitive(path_str, ns) {
  93                 return Ok((prim, Some(path_str.to_owned())))
  94             } else {
  95                 // If resolution failed, it may still be a method
  96                 // because methods are not handled by the resolver
  97                 // If so, bail when we're not looking for a value.
  98                 if ns != ValueNS {
  99                     return Err(())
 100                 }
 101             }
 102
 103             // Try looking for methods and associated items.
 104             let mut split = path_str.rsplitn(2, "::");
 105             let item_name = if let Some(first) = split.next() {
 106                 Symbol::intern(first)
 107             } else {
 108                 return Err(())
 109             };
 110
 111             let mut path = if let Some(second) = split.next() {
 112                 second.to_owned()
 113             } else {
 114                 return Err(())
 115             };
 116
 117             if path == "self" || path == "Self" {
 118                 if let Some(name) = current_item.as_ref() {
 119                     path = name.clone();
 120                 }
 121             }
 122             if let Some(prim) = is_primitive(&path, TypeNS) {
 123                 let did = primitive_impl(cx, &path).ok_or(())?;
 124                 return cx.tcx.associated_items(did)
 125                     .find(|item| item.ident.name == item_name)
 126                     .and_then(|item| match item.kind {
 127                         ty::AssocKind::Method => Some("method"),
 128                         _ => None,
 129                     })
 130                     .map(|out| (prim, Some(format!("{}#{}.{}", path, out, item_name))))
 131                     .ok_or(());
 132             }
 133
 134             let (_, ty_res) = cx.enter_resolver(|resolver| {
 135                 resolver.resolve_str_path_error(DUMMY_SP, &path, TypeNS, module_id)
 136             })?;
 137             if let Res::Err = ty_res {
 138                 return Err(());
 139             }
 140             let ty_res = ty_res.map_id(|_| panic!("unexpected node_id"));
 141             match ty_res {
 142                 Res::Def(DefKind::Struct, did)
 143                 | Res::Def(DefKind::Union, did)
 144                 | Res::Def(DefKind::Enum, did)
 145                 | Res::Def(DefKind::TyAlias, did) => {
 146                     let item = cx.tcx.inherent_impls(did)
 147                                      .iter()
 148                                      .flat_map(|imp| cx.tcx.associated_items(*imp))
 149                                      .find(|item| item.ident.name == item_name);
 150                     if let Some(item) = item {
 151                         let out = match item.kind {
 152                             ty::AssocKind::Method if ns == ValueNS => "method",
 153                             ty::AssocKind::Const if ns == ValueNS => "associatedconstant",
 154                             _ => return Err(())
 155                         };
 156                         Ok((ty_res, Some(format!("{}.{}", out, item_name))))
 157                     } else {
 158                         match cx.tcx.type_of(did).kind {
 159                             ty::Adt(def, _) => {
 160                                 if let Some(item) = if def.is_enum() {
 161                                     def.all_fields().find(|item| item.ident.name == item_name)
 162                                 } else {
 163                                     def.non_enum_variant()
 164                                        .fields
 165                                        .iter()
 166                                        .find(|item| item.ident.name == item_name)
 167                                 } {
 168                                     Ok((ty_res,
 169                                         Some(format!("{}.{}",
 170                                                      if def.is_enum() {
 171                                                          "variant"
 172                                                      } else {
 173                                                          "structfield"
 174                                                      },
 175                                                      item.ident))))
 176                                 } else {
 177                                     Err(())
 178                                 }
 179                             }
 180                             _ => Err(()),
 181                         }
 182                     }
 183                 }
 184                 Res::Def(DefKind::Trait, did) => {
 185                     let item = cx.tcx.associated_item_def_ids(did).iter()
 186                                  .map(|item| cx.tcx.associated_item(*item))
 187                                  .find(|item| item.ident.name == item_name);
 188                     if let Some(item) = item {
 189                         let kind = match item.kind {
 190                             ty::AssocKind::Const if ns == ValueNS => "associatedconstant",
 191                             ty::AssocKind::Type if ns == TypeNS => "associatedtype",
 192                             ty::AssocKind::Method if ns == ValueNS => {
 193                                 if item.defaultness.has_value() {
 194                                     "method"
 195                                 } else {
 196                                     "tymethod"
 197                                 }
 198                             }
 199                             _ => return Err(())
 200                         };
 201
 202                         Ok((ty_res, Some(format!("{}.{}", kind, item_name))))
 203                     } else {
 204                         Err(())
 205                     }
 206                 }
 207                 _ => Err(())
 208             }
 209         } else {
 210             debug!("attempting to resolve item without parent module: {}", path_str);
 211             Err(())
 212         }
 213     }
 214 }
 215
 216 impl<'a, 'tcx> DocFolder for LinkCollector<'a, 'tcx> {
 217     fn fold_item(&mut self, mut item: Item) -> Option<Item> {
 218         let item_hir_id = if item.is_mod() {
 219             if let Some(id) = self.cx.tcx.hir().as_local_hir_id(item.def_id) {
 220                 Some(id)
 221             } else {
 222                 debug!("attempting to fold on a non-local item: {:?}", item);
 223                 return self.fold_item_recur(item);
 224             }
 225         } else {
 226             None
 227         };
 228
 229         // FIXME: get the resolver to work with non-local resolve scopes.
 230         let parent_node = self.cx.as_local_hir_id(item.def_id).and_then(|hir_id| {
 231             // FIXME: this fails hard for impls in non-module scope, but is necessary for the
 232             // current `resolve()` implementation.
 233             match self.cx.tcx.hir().get_module_parent_node(hir_id) {
 234                 id if id != hir_id => Some(id),
 235                 _ => None,
 236             }
 237         });
 238
 239         if parent_node.is_some() {
 240             debug!("got parent node for {:?} {:?}, id {:?}", item.type_(), item.name, item.def_id);
 241         }
 242
 243         let current_item = match item.inner {
 244             ModuleItem(..) => {
 245                 if item.attrs.inner_docs {
 246                     if item_hir_id.unwrap() != hir::CRATE_HIR_ID {
 247                         item.name.clone()
 248                     } else {
 249                         None
 250                     }
 251                 } else {
 252                     match parent_node.or(self.mod_ids.last().cloned()) {
 253                         Some(parent) if parent != hir::CRATE_HIR_ID => {
 254                             // FIXME: can we pull the parent module's name from elsewhere?
 255                             Some(self.cx.tcx.hir().name(parent).to_string())
 256                         }
 257                         _ => None,
 258                     }
 259                 }
 260             }
 261             ImplItem(Impl { ref for_, .. }) => {
 262                 for_.def_id().map(|did| self.cx.tcx.item_name(did).to_string())
 263             }
 264             // we don't display docs on `extern crate` items anyway, so don't process them.
 265             ExternCrateItem(..) => return self.fold_item_recur(item),
 266             ImportItem(Import::Simple(ref name, ..)) => Some(name.clone()),
 267             MacroItem(..) => None,
 268             _ => item.name.clone(),
 269         };
 270
 271         if item.is_mod() && item.attrs.inner_docs {
 272             self.mod_ids.push(item_hir_id.unwrap());
 273         }
 274
 275         let cx = self.cx;
 276         let dox = item.attrs.collapsed_doc_value().unwrap_or_else(String::new);
 277
 278         look_for_tests(&cx, &dox, &item, true);
 279
 280         for (ori_link, link_range) in markdown_links(&dox) {
 281             // Bail early for real links.
 282             if ori_link.contains('/') {
 283                 continue;
 284             }
 285
 286             // [] is mostly likely not supposed to be a link
 287             if ori_link.is_empty() {
 288                 continue;
 289             }
 290
 291             let link = ori_link.replace("`", "");
 292             let (res, fragment) = {
 293                 let mut kind = None;
 294                 let path_str = if let Some(prefix) =
 295                     ["struct@", "enum@", "type@",
 296                      "trait@", "union@"].iter()
 297                                       .find(|p| link.starts_with(**p)) {
 298                     kind = Some(TypeNS);
 299                     link.trim_start_matches(prefix)
 300                 } else if let Some(prefix) =
 301                     ["const@", "static@",
 302                      "value@", "function@", "mod@",
 303                      "fn@", "module@", "method@"]
 304                         .iter().find(|p| link.starts_with(**p)) {
 305                     kind = Some(ValueNS);
 306                     link.trim_start_matches(prefix)
 307                 } else if link.ends_with("()") {
 308                     kind = Some(ValueNS);
 309                     link.trim_end_matches("()")
 310                 } else if link.starts_with("macro@") {
 311                     kind = Some(MacroNS);
 312                     link.trim_start_matches("macro@")
 313                 } else if link.ends_with('!') {
 314                     kind = Some(MacroNS);
 315                     link.trim_end_matches('!')
 316                 } else {
 317                     &link[..]
 318                 }.trim();
 319
 320                 if path_str.contains(|ch: char| !(ch.is_alphanumeric() ||
 321                                                   ch == ':' || ch == '_')) {
 322                     continue;
 323                 }
 324
 325                 match kind {
 326                     Some(ns @ ValueNS) => {
 327                         if let Ok(res) = self.resolve(path_str, ns, &current_item, parent_node) {
 328                             res
 329                         } else {
 330                             resolution_failure(cx, &item, path_str, &dox, link_range);
 331                             // This could just be a normal link or a broken link
 332                             // we could potentially check if something is
 333                             // "intra-doc-link-like" and warn in that case.
 334                             continue;
 335                         }
 336                     }
 337                     Some(ns @ TypeNS) => {
 338                         if let Ok(res) = self.resolve(path_str, ns, &current_item, parent_node) {
 339                             res
 340                         } else {
 341                             resolution_failure(cx, &item, path_str, &dox, link_range);
 342                             // This could just be a normal link.
 343                             continue;
 344                         }
 345                     }
 346                     None => {
 347                         // Try everything!
 348                         let candidates = PerNS {
 349                             macro_ns: macro_resolve(cx, path_str).map(|res| (res, None)),
 350                             type_ns: self
 351                                 .resolve(path_str, TypeNS, &current_item, parent_node)
 352                                 .ok(),
 353                             value_ns: self
 354                                 .resolve(path_str, ValueNS, &current_item, parent_node)
 355                                 .ok()
 356                                 .and_then(|(res, fragment)| {
 357                                     // Constructors are picked up in the type namespace.
 358                                     match res {
 359                                         Res::Def(DefKind::Ctor(..), _) | Res::SelfCtor(..) => None,
 360                                         _ => Some((res, fragment))
 361                                     }
 362                                 }),
 363                         };
 364
 365                         if candidates.is_empty() {
 366                             resolution_failure(cx, &item, path_str, &dox, link_range);
 367                             // this could just be a normal link
 368                             continue;
 369                         }
 370
 371                         let is_unambiguous = candidates.clone().present_items().count() == 1;
 372                         if is_unambiguous {
 373                             candidates.present_items().next().unwrap()
 374                         } else {
 375                             ambiguity_error(
 376                                 cx,
 377                                 &item,
 378                                 path_str,
 379                                 &dox,
 380                                 link_range,
 381                                 candidates.map(|candidate| candidate.map(|(res, _)| res)),
 382                             );
 383                             continue;
 384                         }
 385                     }
 386                     Some(MacroNS) => {
 387                         if let Some(res) = macro_resolve(cx, path_str) {
 388                             (res, None)
 389                         } else {
 390                             resolution_failure(cx, &item, path_str, &dox, link_range);
 391                             continue
 392                         }
 393                     }
 394                 }
 395             };
 396
 397             if let Res::PrimTy(_) = res {
 398                 item.attrs.links.push((ori_link, None, fragment));
 399             } else {
 400                 let id = register_res(cx, res);
 401                 item.attrs.links.push((ori_link, Some(id), fragment));
 402             }
 403         }
 404
 405         if item.is_mod() && !item.attrs.inner_docs {
 406             self.mod_ids.push(item_hir_id.unwrap());
 407         }
 408
 409         if item.is_mod() {
 410             let ret = self.fold_item_recur(item);
 411
 412             self.mod_ids.pop();
 413
 414             ret
 415         } else {
 416             self.fold_item_recur(item)
 417         }
 418     }
 419
 420     // FIXME: if we can resolve intra-doc links from other crates, we can use the stock
 421     // `fold_crate`, but until then we should avoid scanning `krate.external_traits` since those
 422     // will never resolve properly
 423     fn fold_crate(&mut self, mut c: Crate) -> Crate {
 424         c.module = c.module.take().and_then(|module| self.fold_item(module));
 425
 426         c
 427     }
 428 }
 429
 430 /// Resolves a string as a macro.
 431 fn macro_resolve(cx: &DocContext<'_>, path_str: &str) -> Option<Res> {
 432     let path = ast::Path::from_ident(Ident::from_str(path_str));
 433     cx.enter_resolver(|resolver| {
 434         if let Ok((Some(ext), res)) = resolver.resolve_macro_path(
 435             &path, None, &ParentScope::module(resolver.graph_root), false, false
 436         ) {
 437             if let SyntaxExtensionKind::LegacyBang { .. } = ext.kind {
 438                 return Some(res.map_id(|_| panic!("unexpected id")));
 439             }
 440         }
 441         if let Some(res) = resolver.all_macros.get(&Symbol::intern(path_str)) {
 442             return Some(res.map_id(|_| panic!("unexpected id")));
 443         }
 444         None
 445     })
 446 }
 447
 448 /// Reports a resolution failure diagnostic.
 449 ///
 450 /// If we cannot find the exact source span of the resolution failure, we use the span of the
 451 /// documentation attributes themselves. This is a little heavy-handed, so we display the markdown
 452 /// line containing the failure as a note as well.
 453 fn resolution_failure(
 454     cx: &DocContext<'_>,
 455     item: &Item,
 456     path_str: &str,
 457     dox: &str,
 458     link_range: Option<Range<usize>>,
 459 ) {
 460     let hir_id = match cx.as_local_hir_id(item.def_id) {
 461         Some(hir_id) => hir_id,
 462         None => {
 463             // If non-local, no need to check anything.
 464             return;
 465         }
 466     };
 467     let attrs = &item.attrs;
 468     let sp = span_of_attrs(attrs).unwrap_or(item.source.span());
 469
 470     let mut diag = cx.tcx.struct_span_lint_hir(
 471         lint::builtin::INTRA_DOC_LINK_RESOLUTION_FAILURE,
 472         hir_id,
 473         sp,
 474         &format!("`[{}]` cannot be resolved, ignoring it...", path_str),
 475     );
 476     if let Some(link_range) = link_range {
 477         if let Some(sp) = super::source_span_for_markdown_range(cx, dox, &link_range, attrs) {
 478             diag.set_span(sp);
 479             diag.span_label(sp, "cannot be resolved, ignoring");
 480         } else {
 481             // blah blah blah\nblah\nblah [blah] blah blah\nblah blah
 482             //                       ^     ~~~~
 483             //                       |     link_range
 484             //                       last_new_line_offset
 485             let last_new_line_offset = dox[..link_range.start].rfind('\n').map_or(0, |n| n + 1);
 486             let line = dox[last_new_line_offset..].lines().next().unwrap_or("");
 487
 488             // Print the line containing the `link_range` and manually mark it with '^'s.
 489             diag.note(&format!(
 490                 "the link appears in this line:\n\n{line}\n\
 491                  {indicator: <before$}{indicator:^<found$}",
 492                 line=line,
 493                 indicator="",
 494                 before=link_range.start - last_new_line_offset,
 495                 found=link_range.len(),
 496             ));
 497         }
 498     };
 499     diag.help("to escape `[` and `]` characters, just add '\\' before them like \
 500                `\\[` or `\\]`");
 501     diag.emit();
 502 }
 503
 504 fn ambiguity_error(
 505     cx: &DocContext<'_>,
 506     item: &Item,
 507     path_str: &str,
 508     dox: &str,
 509     link_range: Option<Range<usize>>,
 510     candidates: PerNS<Option<Res>>,
 511 ) {
 512     let hir_id = match cx.as_local_hir_id(item.def_id) {
 513         Some(hir_id) => hir_id,
 514         None => {
 515             // If non-local, no need to check anything.
 516             return;
 517         }
 518     };
 519     let attrs = &item.attrs;
 520     let sp = span_of_attrs(attrs).unwrap_or(item.source.span());
 521
 522     let mut msg = format!("`{}` is ", path_str);
 523
 524     let candidates = [TypeNS, ValueNS, MacroNS].iter().filter_map(|&ns| {
 525         candidates[ns].map(|res| (res, ns))
 526     }).collect::<Vec<_>>();
 527     match candidates.as_slice() {
 528         [(first_def, _), (second_def, _)] => {
 529             msg += &format!(
 530                 "both {} {} and {} {}",
 531                 first_def.article(),
 532                 first_def.descr(),
 533                 second_def.article(),
 534                 second_def.descr(),
 535             );
 536         }
 537         _ => {
 538             let mut candidates = candidates.iter().peekable();
 539             while let Some((res, _)) = candidates.next() {
 540                 if candidates.peek().is_some() {
 541                     msg += &format!("{} {}, ", res.article(), res.descr());
 542                 } else {
 543                     msg += &format!("and {} {}", res.article(), res.descr());
 544                 }
 545             }
 546         }
 547     }
 548
 549     let mut diag = cx.tcx.struct_span_lint_hir(
 550         lint::builtin::INTRA_DOC_LINK_RESOLUTION_FAILURE,
 551         hir_id,
 552         sp,
 553         &msg,
 554     );
 555
 556     if let Some(link_range) = link_range {
 557         if let Some(sp) = super::source_span_for_markdown_range(cx, dox, &link_range, attrs) {
 558             diag.set_span(sp);
 559             diag.span_label(sp, "ambiguous link");
 560
 561             for (res, ns) in candidates {
 562                 let (action, mut suggestion) = match res {
 563                     Res::Def(DefKind::Method, _) | Res::Def(DefKind::Fn, _) => {
 564                         ("add parentheses", format!("{}()", path_str))
 565                     }
 566                     Res::Def(DefKind::Macro(..), _) => {
 567                         ("add an exclamation mark", format!("{}!", path_str))
 568                     }
 569                     _ => {
 570                         let type_ = match (res, ns) {
 571                             (Res::Def(DefKind::Const, _), _) => "const",
 572                             (Res::Def(DefKind::Static, _), _) => "static",
 573                             (Res::Def(DefKind::Struct, _), _) => "struct",
 574                             (Res::Def(DefKind::Enum, _), _) => "enum",
 575                             (Res::Def(DefKind::Union, _), _) => "union",
 576                             (Res::Def(DefKind::Trait, _), _) => "trait",
 577                             (Res::Def(DefKind::Mod, _), _) => "module",
 578                             (_, TypeNS) => "type",
 579                             (_, ValueNS) => "value",
 580                             (_, MacroNS) => "macro",
 581                         };
 582
 583                         // FIXME: if this is an implied shortcut link, it's bad style to suggest `@`
 584                         ("prefix with the item type", format!("{}@{}", type_, path_str))
 585                     }
 586                 };
 587
 588                 if dox.bytes().nth(link_range.start) == Some(b'`') {
 589                     suggestion = format!("`{}`", suggestion);
 590                 }
 591
 592                 diag.span_suggestion(
 593                     sp,
 594                     &format!("to link to the {}, {}", res.descr(), action),
 595                     suggestion,
 596                     Applicability::MaybeIncorrect,
 597                 );
 598             }
 599         } else {
 600             // blah blah blah\nblah\nblah [blah] blah blah\nblah blah
 601             //                       ^     ~~~~
 602             //                       |     link_range
 603             //                       last_new_line_offset
 604             let last_new_line_offset = dox[..link_range.start].rfind('\n').map_or(0, |n| n + 1);
 605             let line = dox[last_new_line_offset..].lines().next().unwrap_or("");
 606
 607             // Print the line containing the `link_range` and manually mark it with '^'s.
 608             diag.note(&format!(
 609                 "the link appears in this line:\n\n{line}\n\
 610                  {indicator: <before$}{indicator:^<found$}",
 611                 line=line,
 612                 indicator="",
 613                 before=link_range.start - last_new_line_offset,
 614                 found=link_range.len(),
 615             ));
 616         }
 617     }
 618
 619     diag.emit();
 620 }
 621
 622 /// Given an enum variant's res, return the res of its enum and the associated fragment.
 623 fn handle_variant(cx: &DocContext<'_>, res: Res) -> Result<(Res, Option<String>), ()> {
 624     use rustc::ty::DefIdTree;
 625
 626     let parent = if let Some(parent) = cx.tcx.parent(res.def_id()) {
 627         parent
 628     } else {
 629         return Err(())
 630     };
 631     let parent_def = Res::Def(DefKind::Enum, parent);
 632     let variant = cx.tcx.expect_variant_res(res);
 633     Ok((parent_def, Some(format!("{}.v", variant.ident.name))))
 634 }
 635
 636 const PRIMITIVES: &[(&str, Res)] = &[
 637     ("u8",    Res::PrimTy(hir::PrimTy::Uint(syntax::ast::UintTy::U8))),
 638     ("u16",   Res::PrimTy(hir::PrimTy::Uint(syntax::ast::UintTy::U16))),
 639     ("u32",   Res::PrimTy(hir::PrimTy::Uint(syntax::ast::UintTy::U32))),
 640     ("u64",   Res::PrimTy(hir::PrimTy::Uint(syntax::ast::UintTy::U64))),
 641     ("u128",  Res::PrimTy(hir::PrimTy::Uint(syntax::ast::UintTy::U128))),
 642     ("usize", Res::PrimTy(hir::PrimTy::Uint(syntax::ast::UintTy::Usize))),
 643     ("i8",    Res::PrimTy(hir::PrimTy::Int(syntax::ast::IntTy::I8))),
 644     ("i16",   Res::PrimTy(hir::PrimTy::Int(syntax::ast::IntTy::I16))),
 645     ("i32",   Res::PrimTy(hir::PrimTy::Int(syntax::ast::IntTy::I32))),
 646     ("i64",   Res::PrimTy(hir::PrimTy::Int(syntax::ast::IntTy::I64))),
 647     ("i128",  Res::PrimTy(hir::PrimTy::Int(syntax::ast::IntTy::I128))),
 648     ("isize", Res::PrimTy(hir::PrimTy::Int(syntax::ast::IntTy::Isize))),
 649     ("f32",   Res::PrimTy(hir::PrimTy::Float(syntax::ast::FloatTy::F32))),
 650     ("f64",   Res::PrimTy(hir::PrimTy::Float(syntax::ast::FloatTy::F64))),
 651     ("str",   Res::PrimTy(hir::PrimTy::Str)),
 652     ("bool",  Res::PrimTy(hir::PrimTy::Bool)),
 653     ("char",  Res::PrimTy(hir::PrimTy::Char)),
 654 ];
 655
 656 fn is_primitive(path_str: &str, ns: Namespace) -> Option<Res> {
 657     if ns == TypeNS {
 658         PRIMITIVES.iter().find(|x| x.0 == path_str).map(|x| x.1)
 659     } else {
 660         None
 661     }
 662 }
 663
 664 fn primitive_impl(cx: &DocContext<'_>, path_str: &str) -> Option<DefId> {
 665     let tcx = cx.tcx;
 666     match path_str {
 667         "u8" => tcx.lang_items().u8_impl(),
 668         "u16" => tcx.lang_items().u16_impl(),
 669         "u32" => tcx.lang_items().u32_impl(),
 670         "u64" => tcx.lang_items().u64_impl(),
 671         "u128" => tcx.lang_items().u128_impl(),
 672         "usize" => tcx.lang_items().usize_impl(),
 673         "i8" => tcx.lang_items().i8_impl(),
 674         "i16" => tcx.lang_items().i16_impl(),
 675         "i32" => tcx.lang_items().i32_impl(),
 676         "i64" => tcx.lang_items().i64_impl(),
 677         "i128" => tcx.lang_items().i128_impl(),
 678         "isize" => tcx.lang_items().isize_impl(),
 679         "f32" => tcx.lang_items().f32_impl(),
 680         "f64" => tcx.lang_items().f64_impl(),
 681         "str" => tcx.lang_items().str_impl(),
 682         "bool" => tcx.lang_items().bool_impl(),
 683         "char" => tcx.lang_items().char_impl(),
 684         _ => None,
 685     }
 686 }