src/librustdoc/clean/inline.rs

   1 //! Support for inlining external documentation into the current AST.
   2
   3 use std::iter::once;
   4 use std::sync::Arc;
   5
   6 use thin_vec::{thin_vec, ThinVec};
   7
   8 use rustc_ast as ast;
   9 use rustc_data_structures::fx::FxHashSet;
  10 use rustc_hir as hir;
  11 use rustc_hir::def::{DefKind, Res};
  12 use rustc_hir::def_id::{DefId, DefIdSet, LocalDefId};
  13 use rustc_hir::Mutability;
  14 use rustc_metadata::creader::{CStore, LoadedMacro};
  15 use rustc_middle::ty::{self, TyCtxt};
  16 use rustc_span::hygiene::MacroKind;
  17 use rustc_span::symbol::{kw, sym, Symbol};
  18
  19 use crate::clean::{
  20     self, clean_fn_decl_from_did_and_sig, clean_generics, clean_impl_item, clean_middle_assoc_item,
  21     clean_middle_field, clean_middle_ty, clean_trait_ref_with_bindings, clean_ty,
  22     clean_ty_generics, clean_variant_def, utils, Attributes, AttributesExt, ImplKind, ItemId, Type,
  23 };
  24 use crate::core::DocContext;
  25 use crate::formats::item_type::ItemType;
  26
  27 /// Attempt to inline a definition into this AST.
  28 ///
  29 /// This function will fetch the definition specified, and if it is
  30 /// from another crate it will attempt to inline the documentation
  31 /// from the other crate into this crate.
  32 ///
  33 /// This is primarily used for `pub use` statements which are, in general,
  34 /// implementation details. Inlining the documentation should help provide a
  35 /// better experience when reading the documentation in this use case.
  36 ///
  37 /// The returned value is `None` if the definition could not be inlined,
  38 /// and `Some` of a vector of items if it was successfully expanded.
  39 pub(crate) fn try_inline(
  40     cx: &mut DocContext<'_>,
  41     res: Res,
  42     name: Symbol,
  43     attrs: Option<(&[ast::Attribute], Option<DefId>)>,
  44     visited: &mut DefIdSet,
  45 ) -> Option<Vec<clean::Item>> {
  46     let did = res.opt_def_id()?;
  47     if did.is_local() {
  48         return None;
  49     }
  50     let mut ret = Vec::new();
  51
  52     debug!("attrs={:?}", attrs);
  53
  54     let attrs_without_docs = attrs.map(|(attrs, def_id)| {
  55         (attrs.into_iter().filter(|a| a.doc_str().is_none()).cloned().collect::<Vec<_>>(), def_id)
  56     });
  57     let attrs_without_docs =
  58         attrs_without_docs.as_ref().map(|(attrs, def_id)| (&attrs[..], *def_id));
  59
  60     let import_def_id = attrs.and_then(|(_, def_id)| def_id);
  61     let kind = match res {
  62         Res::Def(DefKind::Trait, did) => {
  63             record_extern_fqn(cx, did, ItemType::Trait);
  64             build_impls(cx, did, attrs_without_docs, &mut ret);
  65             clean::TraitItem(Box::new(build_external_trait(cx, did)))
  66         }
  67         Res::Def(DefKind::Fn, did) => {
  68             record_extern_fqn(cx, did, ItemType::Function);
  69             clean::FunctionItem(build_external_function(cx, did))
  70         }
  71         Res::Def(DefKind::Struct, did) => {
  72             record_extern_fqn(cx, did, ItemType::Struct);
  73             build_impls(cx, did, attrs_without_docs, &mut ret);
  74             clean::StructItem(build_struct(cx, did))
  75         }
  76         Res::Def(DefKind::Union, did) => {
  77             record_extern_fqn(cx, did, ItemType::Union);
  78             build_impls(cx, did, attrs_without_docs, &mut ret);
  79             clean::UnionItem(build_union(cx, did))
  80         }
  81         Res::Def(DefKind::TyAlias, did) => {
  82             record_extern_fqn(cx, did, ItemType::Typedef);
  83             build_impls(cx, did, attrs_without_docs, &mut ret);
  84             clean::TypedefItem(build_type_alias(cx, did))
  85         }
  86         Res::Def(DefKind::Enum, did) => {
  87             record_extern_fqn(cx, did, ItemType::Enum);
  88             build_impls(cx, did, attrs_without_docs, &mut ret);
  89             clean::EnumItem(build_enum(cx, did))
  90         }
  91         Res::Def(DefKind::ForeignTy, did) => {
  92             record_extern_fqn(cx, did, ItemType::ForeignType);
  93             build_impls(cx, did, attrs_without_docs, &mut ret);
  94             clean::ForeignTypeItem
  95         }
  96         // Never inline enum variants but leave them shown as re-exports.
  97         Res::Def(DefKind::Variant, _) => return None,
  98         // Assume that enum variants and struct types are re-exported next to
  99         // their constructors.
 100         Res::Def(DefKind::Ctor(..), _) | Res::SelfCtor(..) => return Some(Vec::new()),
 101         Res::Def(DefKind::Mod, did) => {
 102             record_extern_fqn(cx, did, ItemType::Module);
 103             clean::ModuleItem(build_module(cx, did, visited))
 104         }
 105         Res::Def(DefKind::Static(_), did) => {
 106             record_extern_fqn(cx, did, ItemType::Static);
 107             clean::StaticItem(build_static(cx, did, cx.tcx.is_mutable_static(did)))
 108         }
 109         Res::Def(DefKind::Const, did) => {
 110             record_extern_fqn(cx, did, ItemType::Constant);
 111             clean::ConstantItem(build_const(cx, did))
 112         }
 113         Res::Def(DefKind::Macro(kind), did) => {
 114             let mac = build_macro(cx, did, name, import_def_id, kind);
 115
 116             let type_kind = match kind {
 117                 MacroKind::Bang => ItemType::Macro,
 118                 MacroKind::Attr => ItemType::ProcAttribute,
 119                 MacroKind::Derive => ItemType::ProcDerive,
 120             };
 121             record_extern_fqn(cx, did, type_kind);
 122             mac
 123         }
 124         _ => return None,
 125     };
 126
 127     let (attrs, cfg) = merge_attrs(cx, load_attrs(cx, did), attrs);
 128     cx.inlined.insert(did.into());
 129     let mut item =
 130         clean::Item::from_def_id_and_attrs_and_parts(did, Some(name), kind, Box::new(attrs), cfg);
 131     // The visibility needs to reflect the one from the reexport and not from the "source" DefId.
 132     item.inline_stmt_id = import_def_id;
 133     ret.push(item);
 134     Some(ret)
 135 }
 136
 137 pub(crate) fn try_inline_glob(
 138     cx: &mut DocContext<'_>,
 139     res: Res,
 140     current_mod: LocalDefId,
 141     visited: &mut DefIdSet,
 142     inlined_names: &mut FxHashSet<(ItemType, Symbol)>,
 143 ) -> Option<Vec<clean::Item>> {
 144     let did = res.opt_def_id()?;
 145     if did.is_local() {
 146         return None;
 147     }
 148
 149     match res {
 150         Res::Def(DefKind::Mod, did) => {
 151             // Use the set of module reexports to filter away names that are not actually
 152             // reexported by the glob, e.g. because they are shadowed by something else.
 153             let reexports = cx
 154                 .tcx
 155                 .module_children_local(current_mod)
 156                 .iter()
 157                 .filter(|child| !child.reexport_chain.is_empty())
 158                 .filter_map(|child| child.res.opt_def_id())
 159                 .collect();
 160             let mut items = build_module_items(cx, did, visited, inlined_names, Some(&reexports));
 161             items.retain(|item| {
 162                 if let Some(name) = item.name {
 163                     // If an item with the same type and name already exists,
 164                     // it takes priority over the inlined stuff.
 165                     inlined_names.insert((item.type_(), name))
 166                 } else {
 167                     true
 168                 }
 169             });
 170             Some(items)
 171         }
 172         // glob imports on things like enums aren't inlined even for local exports, so just bail
 173         _ => None,
 174     }
 175 }
 176
 177 pub(crate) fn load_attrs<'hir>(cx: &DocContext<'hir>, did: DefId) -> &'hir [ast::Attribute] {
 178     cx.tcx.get_attrs_unchecked(did)
 179 }
 180
 181 /// Record an external fully qualified name in the external_paths cache.
 182 ///
 183 /// These names are used later on by HTML rendering to generate things like
 184 /// source links back to the original item.
 185 pub(crate) fn record_extern_fqn(cx: &mut DocContext<'_>, did: DefId, kind: ItemType) {
 186     let crate_name = cx.tcx.crate_name(did.krate);
 187
 188     let relative =
 189         cx.tcx.def_path(did).data.into_iter().filter_map(|elem| elem.data.get_opt_name());
 190     let fqn = if let ItemType::Macro = kind {
 191         // Check to see if it is a macro 2.0 or built-in macro
 192         if matches!(
 193             CStore::from_tcx(cx.tcx).load_macro_untracked(did, cx.sess()),
 194             LoadedMacro::MacroDef(def, _)
 195                 if matches!(&def.kind, ast::ItemKind::MacroDef(ast_def)
 196                     if !ast_def.macro_rules)
 197         ) {
 198             once(crate_name).chain(relative).collect()
 199         } else {
 200             vec![crate_name, relative.last().expect("relative was empty")]
 201         }
 202     } else {
 203         once(crate_name).chain(relative).collect()
 204     };
 205
 206     if did.is_local() {
 207         cx.cache.exact_paths.insert(did, fqn);
 208     } else {
 209         cx.cache.external_paths.insert(did, (fqn, kind));
 210     }
 211 }
 212
 213 pub(crate) fn build_external_trait(cx: &mut DocContext<'_>, did: DefId) -> clean::Trait {
 214     let trait_items = cx
 215         .tcx
 216         .associated_items(did)
 217         .in_definition_order()
 218         .map(|item| clean_middle_assoc_item(item, cx))
 219         .collect();
 220
 221     let predicates = cx.tcx.predicates_of(did);
 222     let generics = clean_ty_generics(cx, cx.tcx.generics_of(did), predicates);
 223     let generics = filter_non_trait_generics(did, generics);
 224     let (generics, supertrait_bounds) = separate_supertrait_bounds(generics);
 225     clean::Trait { def_id: did, generics, items: trait_items, bounds: supertrait_bounds }
 226 }
 227
 228 fn build_external_function<'tcx>(cx: &mut DocContext<'tcx>, did: DefId) -> Box<clean::Function> {
 229     let sig = cx.tcx.fn_sig(did).subst_identity();
 230
 231     let late_bound_regions = sig.bound_vars().into_iter().filter_map(|var| match var {
 232         ty::BoundVariableKind::Region(ty::BrNamed(_, name)) if name != kw::UnderscoreLifetime => {
 233             Some(clean::GenericParamDef::lifetime(name))
 234         }
 235         _ => None,
 236     });
 237
 238     let predicates = cx.tcx.explicit_predicates_of(did);
 239     let (generics, decl) = clean::enter_impl_trait(cx, |cx| {
 240         // NOTE: generics need to be cleaned before the decl!
 241         let mut generics = clean_ty_generics(cx, cx.tcx.generics_of(did), predicates);
 242         // FIXME: This does not place parameters in source order (late-bound ones come last)
 243         generics.params.extend(late_bound_regions);
 244         let decl = clean_fn_decl_from_did_and_sig(cx, Some(did), sig);
 245         (generics, decl)
 246     });
 247     Box::new(clean::Function { decl, generics })
 248 }
 249
 250 fn build_enum(cx: &mut DocContext<'_>, did: DefId) -> clean::Enum {
 251     let predicates = cx.tcx.explicit_predicates_of(did);
 252
 253     clean::Enum {
 254         generics: clean_ty_generics(cx, cx.tcx.generics_of(did), predicates),
 255         variants: cx.tcx.adt_def(did).variants().iter().map(|v| clean_variant_def(v, cx)).collect(),
 256     }
 257 }
 258
 259 fn build_struct(cx: &mut DocContext<'_>, did: DefId) -> clean::Struct {
 260     let predicates = cx.tcx.explicit_predicates_of(did);
 261     let variant = cx.tcx.adt_def(did).non_enum_variant();
 262
 263     clean::Struct {
 264         ctor_kind: variant.ctor_kind(),
 265         generics: clean_ty_generics(cx, cx.tcx.generics_of(did), predicates),
 266         fields: variant.fields.iter().map(|x| clean_middle_field(x, cx)).collect(),
 267     }
 268 }
 269
 270 fn build_union(cx: &mut DocContext<'_>, did: DefId) -> clean::Union {
 271     let predicates = cx.tcx.explicit_predicates_of(did);
 272     let variant = cx.tcx.adt_def(did).non_enum_variant();
 273
 274     let generics = clean_ty_generics(cx, cx.tcx.generics_of(did), predicates);
 275     let fields = variant.fields.iter().map(|x| clean_middle_field(x, cx)).collect();
 276     clean::Union { generics, fields }
 277 }
 278
 279 fn build_type_alias(cx: &mut DocContext<'_>, did: DefId) -> Box<clean::Typedef> {
 280     let predicates = cx.tcx.explicit_predicates_of(did);
 281     let type_ = clean_middle_ty(
 282         ty::Binder::dummy(cx.tcx.type_of(did).subst_identity()),
 283         cx,
 284         Some(did),
 285         None,
 286     );
 287
 288     Box::new(clean::Typedef {
 289         type_,
 290         generics: clean_ty_generics(cx, cx.tcx.generics_of(did), predicates),
 291         item_type: None,
 292     })
 293 }
 294
 295 /// Builds all inherent implementations of an ADT (struct/union/enum) or Trait item/path/reexport.
 296 pub(crate) fn build_impls(
 297     cx: &mut DocContext<'_>,
 298     did: DefId,
 299     attrs: Option<(&[ast::Attribute], Option<DefId>)>,
 300     ret: &mut Vec<clean::Item>,
 301 ) {
 302     let _prof_timer = cx.tcx.sess.prof.generic_activity("build_inherent_impls");
 303     let tcx = cx.tcx;
 304
 305     // for each implementation of an item represented by `did`, build the clean::Item for that impl
 306     for &did in tcx.inherent_impls(did).iter() {
 307         build_impl(cx, did, attrs, ret);
 308     }
 309
 310     // This pretty much exists expressly for `dyn Error` traits that exist in the `alloc` crate.
 311     // See also:
 312     //
 313     // * https://github.com/rust-lang/rust/issues/103170 — where it didn't used to get documented
 314     // * https://github.com/rust-lang/rust/pull/99917 — where the feature got used
 315     // * https://github.com/rust-lang/rust/issues/53487 — overall tracking issue for Error
 316     if tcx.has_attr(did, sym::rustc_has_incoherent_inherent_impls) {
 317         use rustc_middle::ty::fast_reject::SimplifiedType::*;
 318         let type_ =
 319             if tcx.is_trait(did) { TraitSimplifiedType(did) } else { AdtSimplifiedType(did) };
 320         for &did in tcx.incoherent_impls(type_) {
 321             build_impl(cx, did, attrs, ret);
 322         }
 323     }
 324 }
 325
 326 pub(crate) fn merge_attrs(
 327     cx: &mut DocContext<'_>,
 328     old_attrs: &[ast::Attribute],
 329     new_attrs: Option<(&[ast::Attribute], Option<DefId>)>,
 330 ) -> (clean::Attributes, Option<Arc<clean::cfg::Cfg>>) {
 331     // NOTE: If we have additional attributes (from a re-export),
 332     // always insert them first. This ensure that re-export
 333     // doc comments show up before the original doc comments
 334     // when we render them.
 335     if let Some((inner, item_id)) = new_attrs {
 336         let mut both = inner.to_vec();
 337         both.extend_from_slice(old_attrs);
 338         (
 339             if let Some(item_id) = item_id {
 340                 Attributes::from_ast_with_additional(old_attrs, (inner, item_id))
 341             } else {
 342                 Attributes::from_ast(&both)
 343             },
 344             both.cfg(cx.tcx, &cx.cache.hidden_cfg),
 345         )
 346     } else {
 347         (Attributes::from_ast(&old_attrs), old_attrs.cfg(cx.tcx, &cx.cache.hidden_cfg))
 348     }
 349 }
 350
 351 /// Inline an `impl`, inherent or of a trait. The `did` must be for an `impl`.
 352 pub(crate) fn build_impl(
 353     cx: &mut DocContext<'_>,
 354     did: DefId,
 355     attrs: Option<(&[ast::Attribute], Option<DefId>)>,
 356     ret: &mut Vec<clean::Item>,
 357 ) {
 358     if !cx.inlined.insert(did.into()) {
 359         return;
 360     }
 361
 362     let tcx = cx.tcx;
 363     let _prof_timer = tcx.sess.prof.generic_activity("build_impl");
 364
 365     let associated_trait = tcx.impl_trait_ref(did).map(ty::EarlyBinder::skip_binder);
 366
 367     // Only inline impl if the implemented trait is
 368     // reachable in rustdoc generated documentation
 369     if !did.is_local() && let Some(traitref) = associated_trait {
 370         let did = traitref.def_id;
 371         if !cx.cache.effective_visibilities.is_directly_public(tcx, did) {
 372             return;
 373         }
 374
 375         if let Some(stab) = tcx.lookup_stability(did) &&
 376             stab.is_unstable() &&
 377             stab.feature == sym::rustc_private
 378         {
 379             return;
 380         }
 381     }
 382
 383     let impl_item = match did.as_local() {
 384         Some(did) => match &tcx.hir().expect_item(did).kind {
 385             hir::ItemKind::Impl(impl_) => Some(impl_),
 386             _ => panic!("`DefID` passed to `build_impl` is not an `impl"),
 387         },
 388         None => None,
 389     };
 390
 391     let for_ = match &impl_item {
 392         Some(impl_) => clean_ty(impl_.self_ty, cx),
 393         None => clean_middle_ty(
 394             ty::Binder::dummy(tcx.type_of(did).subst_identity()),
 395             cx,
 396             Some(did),
 397             None,
 398         ),
 399     };
 400
 401     // Only inline impl if the implementing type is
 402     // reachable in rustdoc generated documentation
 403     if !did.is_local() {
 404         if let Some(did) = for_.def_id(&cx.cache) {
 405             if !cx.cache.effective_visibilities.is_directly_public(tcx, did) {
 406                 return;
 407             }
 408
 409             if let Some(stab) = tcx.lookup_stability(did) {
 410                 if stab.is_unstable() && stab.feature == sym::rustc_private {
 411                     return;
 412                 }
 413             }
 414         }
 415     }
 416
 417     let document_hidden = cx.render_options.document_hidden;
 418     let predicates = tcx.explicit_predicates_of(did);
 419     let (trait_items, generics) = match impl_item {
 420         Some(impl_) => (
 421             impl_
 422                 .items
 423                 .iter()
 424                 .map(|item| tcx.hir().impl_item(item.id))
 425                 .filter(|item| {
 426                     // Filter out impl items whose corresponding trait item has `doc(hidden)`
 427                     // not to document such impl items.
 428                     // For inherent impls, we don't do any filtering, because that's already done in strip_hidden.rs.
 429
 430                     // When `--document-hidden-items` is passed, we don't
 431                     // do any filtering, too.
 432                     if document_hidden {
 433                         return true;
 434                     }
 435                     if let Some(associated_trait) = associated_trait {
 436                         let assoc_kind = match item.kind {
 437                             hir::ImplItemKind::Const(..) => ty::AssocKind::Const,
 438                             hir::ImplItemKind::Fn(..) => ty::AssocKind::Fn,
 439                             hir::ImplItemKind::Type(..) => ty::AssocKind::Type,
 440                         };
 441                         let trait_item = tcx
 442                             .associated_items(associated_trait.def_id)
 443                             .find_by_name_and_kind(
 444                                 tcx,
 445                                 item.ident,
 446                                 assoc_kind,
 447                                 associated_trait.def_id,
 448                             )
 449                             .unwrap(); // SAFETY: For all impl items there exists trait item that has the same name.
 450                         !tcx.is_doc_hidden(trait_item.def_id)
 451                     } else {
 452                         true
 453                     }
 454                 })
 455                 .map(|item| clean_impl_item(item, cx))
 456                 .collect::<Vec<_>>(),
 457             clean_generics(impl_.generics, cx),
 458         ),
 459         None => (
 460             tcx.associated_items(did)
 461                 .in_definition_order()
 462                 .filter(|item| {
 463                     // If this is a trait impl, filter out associated items whose corresponding item
 464                     // in the associated trait is marked `doc(hidden)`.
 465                     // If this is an inherent impl, filter out private associated items.
 466                     if let Some(associated_trait) = associated_trait {
 467                         let trait_item = tcx
 468                             .associated_items(associated_trait.def_id)
 469                             .find_by_name_and_kind(
 470                                 tcx,
 471                                 item.ident(tcx),
 472                                 item.kind,
 473                                 associated_trait.def_id,
 474                             )
 475                             .unwrap(); // corresponding associated item has to exist
 476                         !tcx.is_doc_hidden(trait_item.def_id)
 477                     } else {
 478                         item.visibility(tcx).is_public()
 479                     }
 480                 })
 481                 .map(|item| clean_middle_assoc_item(item, cx))
 482                 .collect::<Vec<_>>(),
 483             clean::enter_impl_trait(cx, |cx| {
 484                 clean_ty_generics(cx, tcx.generics_of(did), predicates)
 485             }),
 486         ),
 487     };
 488     let polarity = tcx.impl_polarity(did);
 489     let trait_ = associated_trait
 490         .map(|t| clean_trait_ref_with_bindings(cx, ty::Binder::dummy(t), ThinVec::new()));
 491     if trait_.as_ref().map(|t| t.def_id()) == tcx.lang_items().deref_trait() {
 492         super::build_deref_target_impls(cx, &trait_items, ret);
 493     }
 494
 495     // Return if the trait itself or any types of the generic parameters are doc(hidden).
 496     let mut stack: Vec<&Type> = vec![&for_];
 497
 498     if let Some(did) = trait_.as_ref().map(|t| t.def_id()) {
 499         if tcx.is_doc_hidden(did) {
 500             return;
 501         }
 502     }
 503     if let Some(generics) = trait_.as_ref().and_then(|t| t.generics()) {
 504         stack.extend(generics);
 505     }
 506
 507     while let Some(ty) = stack.pop() {
 508         if let Some(did) = ty.def_id(&cx.cache) && tcx.is_doc_hidden(did) {
 509             return;
 510         }
 511         if let Some(generics) = ty.generics() {
 512             stack.extend(generics);
 513         }
 514     }
 515
 516     if let Some(did) = trait_.as_ref().map(|t| t.def_id()) {
 517         record_extern_trait(cx, did);
 518     }
 519
 520     let (merged_attrs, cfg) = merge_attrs(cx, load_attrs(cx, did), attrs);
 521     trace!("merged_attrs={:?}", merged_attrs);
 522
 523     trace!(
 524         "build_impl: impl {:?} for {:?}",
 525         trait_.as_ref().map(|t| t.def_id()),
 526         for_.def_id(&cx.cache)
 527     );
 528     ret.push(clean::Item::from_def_id_and_attrs_and_parts(
 529         did,
 530         None,
 531         clean::ImplItem(Box::new(clean::Impl {
 532             unsafety: hir::Unsafety::Normal,
 533             generics,
 534             trait_,
 535             for_,
 536             items: trait_items,
 537             polarity,
 538             kind: if utils::has_doc_flag(tcx, did, sym::fake_variadic) {
 539                 ImplKind::FakeVariadic
 540             } else {
 541                 ImplKind::Normal
 542             },
 543         })),
 544         Box::new(merged_attrs),
 545         cfg,
 546     ));
 547 }
 548
 549 fn build_module(cx: &mut DocContext<'_>, did: DefId, visited: &mut DefIdSet) -> clean::Module {
 550     let items = build_module_items(cx, did, visited, &mut FxHashSet::default(), None);
 551
 552     let span = clean::Span::new(cx.tcx.def_span(did));
 553     clean::Module { items, span }
 554 }
 555
 556 fn build_module_items(
 557     cx: &mut DocContext<'_>,
 558     did: DefId,
 559     visited: &mut DefIdSet,
 560     inlined_names: &mut FxHashSet<(ItemType, Symbol)>,
 561     allowed_def_ids: Option<&DefIdSet>,
 562 ) -> Vec<clean::Item> {
 563     let mut items = Vec::new();
 564
 565     // If we're re-exporting a re-export it may actually re-export something in
 566     // two namespaces, so the target may be listed twice. Make sure we only
 567     // visit each node at most once.
 568     for item in cx.tcx.module_children(did).iter() {
 569         if item.vis.is_public() {
 570             let res = item.res.expect_non_local();
 571             if let Some(def_id) = res.opt_def_id()
 572                 && let Some(allowed_def_ids) = allowed_def_ids
 573                 && !allowed_def_ids.contains(&def_id) {
 574                 continue;
 575             }
 576             if let Some(def_id) = res.mod_def_id() {
 577                 // If we're inlining a glob import, it's possible to have
 578                 // two distinct modules with the same name. We don't want to
 579                 // inline it, or mark any of its contents as visited.
 580                 if did == def_id
 581                     || inlined_names.contains(&(ItemType::Module, item.ident.name))
 582                     || !visited.insert(def_id)
 583                 {
 584                     continue;
 585                 }
 586             }
 587             if let Res::PrimTy(p) = res {
 588                 // Primitive types can't be inlined so generate an import instead.
 589                 let prim_ty = clean::PrimitiveType::from(p);
 590                 items.push(clean::Item {
 591                     name: None,
 592                     attrs: Box::new(clean::Attributes::default()),
 593                     // We can use the item's `DefId` directly since the only information ever used
 594                     // from it is `DefId.krate`.
 595                     item_id: ItemId::DefId(did),
 596                     kind: Box::new(clean::ImportItem(clean::Import::new_simple(
 597                         item.ident.name,
 598                         clean::ImportSource {
 599                             path: clean::Path {
 600                                 res,
 601                                 segments: thin_vec![clean::PathSegment {
 602                                     name: prim_ty.as_sym(),
 603                                     args: clean::GenericArgs::AngleBracketed {
 604                                         args: Default::default(),
 605                                         bindings: ThinVec::new(),
 606                                     },
 607                                 }],
 608                             },
 609                             did: None,
 610                         },
 611                         true,
 612                     ))),
 613                     cfg: None,
 614                     inline_stmt_id: None,
 615                 });
 616             } else if let Some(i) = try_inline(cx, res, item.ident.name, None, visited) {
 617                 items.extend(i)
 618             }
 619         }
 620     }
 621
 622     items
 623 }
 624
 625 pub(crate) fn print_inlined_const(tcx: TyCtxt<'_>, did: DefId) -> String {
 626     if let Some(did) = did.as_local() {
 627         let hir_id = tcx.hir().local_def_id_to_hir_id(did);
 628         rustc_hir_pretty::id_to_string(&tcx.hir(), hir_id)
 629     } else {
 630         tcx.rendered_const(did).clone()
 631     }
 632 }
 633
 634 fn build_const(cx: &mut DocContext<'_>, def_id: DefId) -> clean::Constant {
 635     clean::Constant {
 636         type_: clean_middle_ty(
 637             ty::Binder::dummy(cx.tcx.type_of(def_id).subst_identity()),
 638             cx,
 639             Some(def_id),
 640             None,
 641         ),
 642         kind: clean::ConstantKind::Extern { def_id },
 643     }
 644 }
 645
 646 fn build_static(cx: &mut DocContext<'_>, did: DefId, mutable: bool) -> clean::Static {
 647     clean::Static {
 648         type_: clean_middle_ty(
 649             ty::Binder::dummy(cx.tcx.type_of(did).subst_identity()),
 650             cx,
 651             Some(did),
 652             None,
 653         ),
 654         mutability: if mutable { Mutability::Mut } else { Mutability::Not },
 655         expr: None,
 656     }
 657 }
 658
 659 fn build_macro(
 660     cx: &mut DocContext<'_>,
 661     def_id: DefId,
 662     name: Symbol,
 663     import_def_id: Option<DefId>,
 664     macro_kind: MacroKind,
 665 ) -> clean::ItemKind {
 666     match CStore::from_tcx(cx.tcx).load_macro_untracked(def_id, cx.sess()) {
 667         LoadedMacro::MacroDef(item_def, _) => match macro_kind {
 668             MacroKind::Bang => {
 669                 if let ast::ItemKind::MacroDef(ref def) = item_def.kind {
 670                     let vis = cx.tcx.visibility(import_def_id.unwrap_or(def_id));
 671                     clean::MacroItem(clean::Macro {
 672                         source: utils::display_macro_source(cx, name, def, def_id, vis),
 673                     })
 674                 } else {
 675                     unreachable!()
 676                 }
 677             }
 678             MacroKind::Derive | MacroKind::Attr => {
 679                 clean::ProcMacroItem(clean::ProcMacro { kind: macro_kind, helpers: Vec::new() })
 680             }
 681         },
 682         LoadedMacro::ProcMacro(ext) => clean::ProcMacroItem(clean::ProcMacro {
 683             kind: ext.macro_kind(),
 684             helpers: ext.helper_attrs,
 685         }),
 686     }
 687 }
 688
 689 /// A trait's generics clause actually contains all of the predicates for all of
 690 /// its associated types as well. We specifically move these clauses to the
 691 /// associated types instead when displaying, so when we're generating the
 692 /// generics for the trait itself we need to be sure to remove them.
 693 /// We also need to remove the implied "recursive" Self: Trait bound.
 694 ///
 695 /// The inverse of this filtering logic can be found in the `Clean`
 696 /// implementation for `AssociatedType`
 697 fn filter_non_trait_generics(trait_did: DefId, mut g: clean::Generics) -> clean::Generics {
 698     for pred in &mut g.where_predicates {
 699         match *pred {
 700             clean::WherePredicate::BoundPredicate {
 701                 ty: clean::Generic(ref s),
 702                 ref mut bounds,
 703                 ..
 704             } if *s == kw::SelfUpper => {
 705                 bounds.retain(|bound| match bound {
 706                     clean::GenericBound::TraitBound(clean::PolyTrait { trait_, .. }, _) => {
 707                         trait_.def_id() != trait_did
 708                     }
 709                     _ => true,
 710                 });
 711             }
 712             _ => {}
 713         }
 714     }
 715
 716     g.where_predicates.retain(|pred| match pred {
 717         clean::WherePredicate::BoundPredicate {
 718             ty:
 719                 clean::QPath(box clean::QPathData {
 720                     self_type: clean::Generic(ref s),
 721                     trait_: Some(trait_),
 722                     ..
 723                 }),
 724             bounds,
 725             ..
 726         } => !(bounds.is_empty() || *s == kw::SelfUpper && trait_.def_id() == trait_did),
 727         _ => true,
 728     });
 729     g
 730 }
 731
 732 /// Supertrait bounds for a trait are also listed in the generics coming from
 733 /// the metadata for a crate, so we want to separate those out and create a new
 734 /// list of explicit supertrait bounds to render nicely.
 735 fn separate_supertrait_bounds(
 736     mut g: clean::Generics,
 737 ) -> (clean::Generics, Vec<clean::GenericBound>) {
 738     let mut ty_bounds = Vec::new();
 739     g.where_predicates.retain(|pred| match *pred {
 740         clean::WherePredicate::BoundPredicate { ty: clean::Generic(ref s), ref bounds, .. }
 741             if *s == kw::SelfUpper =>
 742         {
 743             ty_bounds.extend(bounds.iter().cloned());
 744             false
 745         }
 746         _ => true,
 747     });
 748     (g, ty_bounds)
 749 }
 750
 751 pub(crate) fn record_extern_trait(cx: &mut DocContext<'_>, did: DefId) {
 752     if did.is_local() {
 753         return;
 754     }
 755
 756     {
 757         if cx.external_traits.borrow().contains_key(&did) || cx.active_extern_traits.contains(&did)
 758         {
 759             return;
 760         }
 761     }
 762
 763     {
 764         cx.active_extern_traits.insert(did);
 765     }
 766
 767     debug!("record_extern_trait: {:?}", did);
 768     let trait_ = build_external_trait(cx, did);
 769
 770     cx.external_traits.borrow_mut().insert(did, trait_);
 771     cx.active_extern_traits.remove(&did);
 772 }