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, LocalModDefId};
  13 use rustc_hir::Mutability;
  14 use rustc_metadata::creader::{CStore, LoadedMacro};
  15 use rustc_middle::ty::fast_reject::SimplifiedType;
  16 use rustc_middle::ty::{self, TyCtxt};
  17 use rustc_span::def_id::LOCAL_CRATE;
  18 use rustc_span::hygiene::MacroKind;
  19 use rustc_span::symbol::{kw, sym, Symbol};
  20
  21 use crate::clean::{
  22     self, clean_bound_vars, clean_generics, clean_impl_item, clean_middle_assoc_item,
  23     clean_middle_field, clean_middle_ty, clean_poly_fn_sig, clean_trait_ref_with_bindings,
  24     clean_ty, clean_ty_alias_inner_type, clean_ty_generics, clean_variant_def, utils, Attributes,
  25     AttributesExt, ImplKind, ItemId, Type,
  26 };
  27 use crate::core::DocContext;
  28 use crate::formats::item_type::ItemType;
  29
  30 use super::Item;
  31
  32 /// Attempt to inline a definition into this AST.
  33 ///
  34 /// This function will fetch the definition specified, and if it is
  35 /// from another crate it will attempt to inline the documentation
  36 /// from the other crate into this crate.
  37 ///
  38 /// This is primarily used for `pub use` statements which are, in general,
  39 /// implementation details. Inlining the documentation should help provide a
  40 /// better experience when reading the documentation in this use case.
  41 ///
  42 /// The returned value is `None` if the definition could not be inlined,
  43 /// and `Some` of a vector of items if it was successfully expanded.
  44 pub(crate) fn try_inline(
  45     cx: &mut DocContext<'_>,
  46     res: Res,
  47     name: Symbol,
  48     attrs: Option<(&[ast::Attribute], Option<DefId>)>,
  49     visited: &mut DefIdSet,
  50 ) -> Option<Vec<clean::Item>> {
  51     let did = res.opt_def_id()?;
  52     if did.is_local() {
  53         return None;
  54     }
  55     let mut ret = Vec::new();
  56
  57     debug!("attrs={attrs:?}");
  58
  59     let attrs_without_docs = attrs.map(|(attrs, def_id)| {
  60         (attrs.into_iter().filter(|a| a.doc_str().is_none()).cloned().collect::<Vec<_>>(), def_id)
  61     });
  62     let attrs_without_docs =
  63         attrs_without_docs.as_ref().map(|(attrs, def_id)| (&attrs[..], *def_id));
  64
  65     let import_def_id = attrs.and_then(|(_, def_id)| def_id);
  66
  67     let kind = match res {
  68         Res::Def(DefKind::Trait, did) => {
  69             record_extern_fqn(cx, did, ItemType::Trait);
  70             cx.with_param_env(did, |cx| {
  71                 build_impls(cx, did, attrs_without_docs, &mut ret);
  72                 clean::TraitItem(Box::new(build_external_trait(cx, did)))
  73             })
  74         }
  75         Res::Def(DefKind::Fn, did) => {
  76             record_extern_fqn(cx, did, ItemType::Function);
  77             cx.with_param_env(did, |cx| {
  78                 clean::enter_impl_trait(cx, |cx| clean::FunctionItem(build_function(cx, did)))
  79             })
  80         }
  81         Res::Def(DefKind::Struct, did) => {
  82             record_extern_fqn(cx, did, ItemType::Struct);
  83             cx.with_param_env(did, |cx| {
  84                 build_impls(cx, did, attrs_without_docs, &mut ret);
  85                 clean::StructItem(build_struct(cx, did))
  86             })
  87         }
  88         Res::Def(DefKind::Union, did) => {
  89             record_extern_fqn(cx, did, ItemType::Union);
  90             cx.with_param_env(did, |cx| {
  91                 build_impls(cx, did, attrs_without_docs, &mut ret);
  92                 clean::UnionItem(build_union(cx, did))
  93             })
  94         }
  95         Res::Def(DefKind::TyAlias, did) => {
  96             record_extern_fqn(cx, did, ItemType::TypeAlias);
  97             cx.with_param_env(did, |cx| {
  98                 build_impls(cx, did, attrs_without_docs, &mut ret);
  99                 clean::TypeAliasItem(build_type_alias(cx, did, &mut ret))
 100             })
 101         }
 102         Res::Def(DefKind::Enum, did) => {
 103             record_extern_fqn(cx, did, ItemType::Enum);
 104             cx.with_param_env(did, |cx| {
 105                 build_impls(cx, did, attrs_without_docs, &mut ret);
 106                 clean::EnumItem(build_enum(cx, did))
 107             })
 108         }
 109         Res::Def(DefKind::ForeignTy, did) => {
 110             record_extern_fqn(cx, did, ItemType::ForeignType);
 111             cx.with_param_env(did, |cx| {
 112                 build_impls(cx, did, attrs_without_docs, &mut ret);
 113                 clean::ForeignTypeItem
 114             })
 115         }
 116         // Never inline enum variants but leave them shown as re-exports.
 117         Res::Def(DefKind::Variant, _) => return None,
 118         // Assume that enum variants and struct types are re-exported next to
 119         // their constructors.
 120         Res::Def(DefKind::Ctor(..), _) | Res::SelfCtor(..) => return Some(Vec::new()),
 121         Res::Def(DefKind::Mod, did) => {
 122             record_extern_fqn(cx, did, ItemType::Module);
 123             clean::ModuleItem(build_module(cx, did, visited))
 124         }
 125         Res::Def(DefKind::Static { .. }, did) => {
 126             record_extern_fqn(cx, did, ItemType::Static);
 127             cx.with_param_env(did, |cx| {
 128                 clean::StaticItem(build_static(cx, did, cx.tcx.is_mutable_static(did)))
 129             })
 130         }
 131         Res::Def(DefKind::Const, did) => {
 132             record_extern_fqn(cx, did, ItemType::Constant);
 133             cx.with_param_env(did, |cx| clean::ConstantItem(build_const(cx, did)))
 134         }
 135         Res::Def(DefKind::Macro(kind), did) => {
 136             let is_doc_hidden = cx.tcx.is_doc_hidden(did)
 137                 || attrs_without_docs
 138                     .map(|(attrs, _)| attrs)
 139                     .is_some_and(|attrs| utils::attrs_have_doc_flag(attrs.iter(), sym::hidden));
 140             let mac = build_macro(cx, did, name, import_def_id, kind, is_doc_hidden);
 141
 142             let type_kind = match kind {
 143                 MacroKind::Bang => ItemType::Macro,
 144                 MacroKind::Attr => ItemType::ProcAttribute,
 145                 MacroKind::Derive => ItemType::ProcDerive,
 146             };
 147             record_extern_fqn(cx, did, type_kind);
 148             mac
 149         }
 150         _ => return None,
 151     };
 152
 153     cx.inlined.insert(did.into());
 154     let mut item = crate::clean::generate_item_with_correct_attrs(
 155         cx,
 156         kind,
 157         did,
 158         name,
 159         import_def_id.and_then(|def_id| def_id.as_local()),
 160         None,
 161     );
 162     // The visibility needs to reflect the one from the reexport and not from the "source" DefId.
 163     item.inline_stmt_id = import_def_id;
 164     ret.push(item);
 165     Some(ret)
 166 }
 167
 168 pub(crate) fn try_inline_glob(
 169     cx: &mut DocContext<'_>,
 170     res: Res,
 171     current_mod: LocalModDefId,
 172     visited: &mut DefIdSet,
 173     inlined_names: &mut FxHashSet<(ItemType, Symbol)>,
 174     import: &hir::Item<'_>,
 175 ) -> Option<Vec<clean::Item>> {
 176     let did = res.opt_def_id()?;
 177     if did.is_local() {
 178         return None;
 179     }
 180
 181     match res {
 182         Res::Def(DefKind::Mod, did) => {
 183             // Use the set of module reexports to filter away names that are not actually
 184             // reexported by the glob, e.g. because they are shadowed by something else.
 185             let reexports = cx
 186                 .tcx
 187                 .module_children_local(current_mod.to_local_def_id())
 188                 .iter()
 189                 .filter(|child| !child.reexport_chain.is_empty())
 190                 .filter_map(|child| child.res.opt_def_id())
 191                 .filter(|def_id| !cx.tcx.is_doc_hidden(def_id))
 192                 .collect();
 193             let attrs = cx.tcx.hir().attrs(import.hir_id());
 194             let mut items = build_module_items(
 195                 cx,
 196                 did,
 197                 visited,
 198                 inlined_names,
 199                 Some(&reexports),
 200                 Some((attrs, Some(import.owner_id.def_id.to_def_id()))),
 201             );
 202             items.retain(|item| {
 203                 if let Some(name) = item.name {
 204                     // If an item with the same type and name already exists,
 205                     // it takes priority over the inlined stuff.
 206                     inlined_names.insert((item.type_(), name))
 207                 } else {
 208                     true
 209                 }
 210             });
 211             Some(items)
 212         }
 213         // glob imports on things like enums aren't inlined even for local exports, so just bail
 214         _ => None,
 215     }
 216 }
 217
 218 pub(crate) fn load_attrs<'hir>(cx: &DocContext<'hir>, did: DefId) -> &'hir [ast::Attribute] {
 219     cx.tcx.get_attrs_unchecked(did)
 220 }
 221
 222 pub(crate) fn item_relative_path(tcx: TyCtxt<'_>, def_id: DefId) -> Vec<Symbol> {
 223     tcx.def_path(def_id)
 224         .data
 225         .into_iter()
 226         .filter_map(|elem| {
 227             // extern blocks (and a few others things) have an empty name.
 228             match elem.data.get_opt_name() {
 229                 Some(s) if !s.is_empty() => Some(s),
 230                 _ => None,
 231             }
 232         })
 233         .collect()
 234 }
 235
 236 /// Record an external fully qualified name in the external_paths cache.
 237 ///
 238 /// These names are used later on by HTML rendering to generate things like
 239 /// source links back to the original item.
 240 pub(crate) fn record_extern_fqn(cx: &mut DocContext<'_>, did: DefId, kind: ItemType) {
 241     if did.is_local() {
 242         if cx.cache.exact_paths.contains_key(&did) {
 243             return;
 244         }
 245     } else if cx.cache.external_paths.contains_key(&did) {
 246         return;
 247     }
 248
 249     let crate_name = cx.tcx.crate_name(did.krate);
 250
 251     let relative = item_relative_path(cx.tcx, did);
 252     let fqn = if let ItemType::Macro = kind {
 253         // Check to see if it is a macro 2.0 or built-in macro
 254         if matches!(
 255             CStore::from_tcx(cx.tcx).load_macro_untracked(did, cx.tcx),
 256             LoadedMacro::MacroDef(def, _)
 257                 if matches!(&def.kind, ast::ItemKind::MacroDef(ast_def)
 258                     if !ast_def.macro_rules)
 259         ) {
 260             once(crate_name).chain(relative).collect()
 261         } else {
 262             vec![crate_name, *relative.last().expect("relative was empty")]
 263         }
 264     } else {
 265         once(crate_name).chain(relative).collect()
 266     };
 267
 268     if did.is_local() {
 269         cx.cache.exact_paths.insert(did, fqn);
 270     } else {
 271         cx.cache.external_paths.insert(did, (fqn, kind));
 272     }
 273 }
 274
 275 pub(crate) fn build_external_trait(cx: &mut DocContext<'_>, did: DefId) -> clean::Trait {
 276     let trait_items = cx
 277         .tcx
 278         .associated_items(did)
 279         .in_definition_order()
 280         .filter(|item| !item.is_impl_trait_in_trait())
 281         .map(|item| clean_middle_assoc_item(item, cx))
 282         .collect();
 283
 284     let predicates = cx.tcx.predicates_of(did);
 285     let generics = clean_ty_generics(cx, cx.tcx.generics_of(did), predicates);
 286     let generics = filter_non_trait_generics(did, generics);
 287     let (generics, supertrait_bounds) = separate_supertrait_bounds(generics);
 288     clean::Trait { def_id: did, generics, items: trait_items, bounds: supertrait_bounds }
 289 }
 290
 291 pub(crate) fn build_function<'tcx>(
 292     cx: &mut DocContext<'tcx>,
 293     def_id: DefId,
 294 ) -> Box<clean::Function> {
 295     let sig = cx.tcx.fn_sig(def_id).instantiate_identity();
 296     // The generics need to be cleaned before the signature.
 297     let mut generics =
 298         clean_ty_generics(cx, cx.tcx.generics_of(def_id), cx.tcx.explicit_predicates_of(def_id));
 299     let bound_vars = clean_bound_vars(sig.bound_vars());
 300
 301     // At the time of writing early & late-bound params are stored separately in rustc,
 302     // namely in `generics.params` and `bound_vars` respectively.
 303     //
 304     // To reestablish the original source code order of the generic parameters, we
 305     // need to manually sort them by their definition span after concatenation.
 306     //
 307     // See also:
 308     // * https://rustc-dev-guide.rust-lang.org/bound-vars-and-params.html
 309     // * https://rustc-dev-guide.rust-lang.org/what-does-early-late-bound-mean.html
 310     let has_early_bound_params = !generics.params.is_empty();
 311     let has_late_bound_params = !bound_vars.is_empty();
 312     generics.params.extend(bound_vars);
 313     if has_early_bound_params && has_late_bound_params {
 314         // If this ever becomes a performances bottleneck either due to the sorting
 315         // or due to the query calls, consider inserting the late-bound lifetime params
 316         // right after the last early-bound lifetime param followed by only sorting
 317         // the slice of lifetime params.
 318         generics.params.sort_by_key(|param| cx.tcx.def_ident_span(param.def_id).unwrap());
 319     }
 320
 321     let decl = clean_poly_fn_sig(cx, Some(def_id), sig);
 322
 323     Box::new(clean::Function { decl, generics })
 324 }
 325
 326 fn build_enum(cx: &mut DocContext<'_>, did: DefId) -> clean::Enum {
 327     let predicates = cx.tcx.explicit_predicates_of(did);
 328
 329     clean::Enum {
 330         generics: clean_ty_generics(cx, cx.tcx.generics_of(did), predicates),
 331         variants: cx.tcx.adt_def(did).variants().iter().map(|v| clean_variant_def(v, cx)).collect(),
 332     }
 333 }
 334
 335 fn build_struct(cx: &mut DocContext<'_>, did: DefId) -> clean::Struct {
 336     let predicates = cx.tcx.explicit_predicates_of(did);
 337     let variant = cx.tcx.adt_def(did).non_enum_variant();
 338
 339     clean::Struct {
 340         ctor_kind: variant.ctor_kind(),
 341         generics: clean_ty_generics(cx, cx.tcx.generics_of(did), predicates),
 342         fields: variant.fields.iter().map(|x| clean_middle_field(x, cx)).collect(),
 343     }
 344 }
 345
 346 fn build_union(cx: &mut DocContext<'_>, did: DefId) -> clean::Union {
 347     let predicates = cx.tcx.explicit_predicates_of(did);
 348     let variant = cx.tcx.adt_def(did).non_enum_variant();
 349
 350     let generics = clean_ty_generics(cx, cx.tcx.generics_of(did), predicates);
 351     let fields = variant.fields.iter().map(|x| clean_middle_field(x, cx)).collect();
 352     clean::Union { generics, fields }
 353 }
 354
 355 fn build_type_alias(
 356     cx: &mut DocContext<'_>,
 357     did: DefId,
 358     ret: &mut Vec<Item>,
 359 ) -> Box<clean::TypeAlias> {
 360     let predicates = cx.tcx.explicit_predicates_of(did);
 361     let ty = cx.tcx.type_of(did).instantiate_identity();
 362     let type_ = clean_middle_ty(ty::Binder::dummy(ty), cx, Some(did), None);
 363     let inner_type = clean_ty_alias_inner_type(ty, cx, ret);
 364
 365     Box::new(clean::TypeAlias {
 366         type_,
 367         generics: clean_ty_generics(cx, cx.tcx.generics_of(did), predicates),
 368         inner_type,
 369         item_type: None,
 370     })
 371 }
 372
 373 /// Builds all inherent implementations of an ADT (struct/union/enum) or Trait item/path/reexport.
 374 pub(crate) fn build_impls(
 375     cx: &mut DocContext<'_>,
 376     did: DefId,
 377     attrs: Option<(&[ast::Attribute], Option<DefId>)>,
 378     ret: &mut Vec<clean::Item>,
 379 ) {
 380     let _prof_timer = cx.tcx.sess.prof.generic_activity("build_inherent_impls");
 381     let tcx = cx.tcx;
 382
 383     // for each implementation of an item represented by `did`, build the clean::Item for that impl
 384     for &did in tcx.inherent_impls(did).into_iter().flatten() {
 385         cx.with_param_env(did, |cx| {
 386             build_impl(cx, did, attrs, ret);
 387         });
 388     }
 389
 390     // This pretty much exists expressly for `dyn Error` traits that exist in the `alloc` crate.
 391     // See also:
 392     //
 393     // * https://github.com/rust-lang/rust/issues/103170 — where it didn't used to get documented
 394     // * https://github.com/rust-lang/rust/pull/99917 — where the feature got used
 395     // * https://github.com/rust-lang/rust/issues/53487 — overall tracking issue for Error
 396     if tcx.has_attr(did, sym::rustc_has_incoherent_inherent_impls) {
 397         let type_ =
 398             if tcx.is_trait(did) { SimplifiedType::Trait(did) } else { SimplifiedType::Adt(did) };
 399         for &did in tcx.incoherent_impls(type_).into_iter().flatten() {
 400             cx.with_param_env(did, |cx| {
 401                 build_impl(cx, did, attrs, ret);
 402             });
 403         }
 404     }
 405 }
 406
 407 pub(crate) fn merge_attrs(
 408     cx: &mut DocContext<'_>,
 409     old_attrs: &[ast::Attribute],
 410     new_attrs: Option<(&[ast::Attribute], Option<DefId>)>,
 411 ) -> (clean::Attributes, Option<Arc<clean::cfg::Cfg>>) {
 412     // NOTE: If we have additional attributes (from a re-export),
 413     // always insert them first. This ensure that re-export
 414     // doc comments show up before the original doc comments
 415     // when we render them.
 416     if let Some((inner, item_id)) = new_attrs {
 417         let mut both = inner.to_vec();
 418         both.extend_from_slice(old_attrs);
 419         (
 420             if let Some(item_id) = item_id {
 421                 Attributes::from_ast_with_additional(old_attrs, (inner, item_id))
 422             } else {
 423                 Attributes::from_ast(&both)
 424             },
 425             both.cfg(cx.tcx, &cx.cache.hidden_cfg),
 426         )
 427     } else {
 428         (Attributes::from_ast(&old_attrs), old_attrs.cfg(cx.tcx, &cx.cache.hidden_cfg))
 429     }
 430 }
 431
 432 /// Inline an `impl`, inherent or of a trait. The `did` must be for an `impl`.
 433 pub(crate) fn build_impl(
 434     cx: &mut DocContext<'_>,
 435     did: DefId,
 436     attrs: Option<(&[ast::Attribute], Option<DefId>)>,
 437     ret: &mut Vec<clean::Item>,
 438 ) {
 439     if !cx.inlined.insert(did.into()) {
 440         return;
 441     }
 442
 443     let tcx = cx.tcx;
 444     let _prof_timer = tcx.sess.prof.generic_activity("build_impl");
 445
 446     let associated_trait = tcx.impl_trait_ref(did).map(ty::EarlyBinder::skip_binder);
 447
 448     // Do not inline compiler-internal items unless we're a compiler-internal crate.
 449     let is_compiler_internal = |did| {
 450         tcx.lookup_stability(did)
 451             .is_some_and(|stab| stab.is_unstable() && stab.feature == sym::rustc_private)
 452     };
 453     let document_compiler_internal = is_compiler_internal(LOCAL_CRATE.as_def_id());
 454     let is_directly_public = |cx: &mut DocContext<'_>, did| {
 455         cx.cache.effective_visibilities.is_directly_public(tcx, did)
 456             && (document_compiler_internal || !is_compiler_internal(did))
 457     };
 458
 459     // Only inline impl if the implemented trait is
 460     // reachable in rustdoc generated documentation
 461     if !did.is_local()
 462         && let Some(traitref) = associated_trait
 463         && !is_directly_public(cx, traitref.def_id)
 464     {
 465         return;
 466     }
 467
 468     let impl_item = match did.as_local() {
 469         Some(did) => match &tcx.hir().expect_item(did).kind {
 470             hir::ItemKind::Impl(impl_) => Some(impl_),
 471             _ => panic!("`DefID` passed to `build_impl` is not an `impl"),
 472         },
 473         None => None,
 474     };
 475
 476     let for_ = match &impl_item {
 477         Some(impl_) => clean_ty(impl_.self_ty, cx),
 478         None => clean_middle_ty(
 479             ty::Binder::dummy(tcx.type_of(did).instantiate_identity()),
 480             cx,
 481             Some(did),
 482             None,
 483         ),
 484     };
 485
 486     // Only inline impl if the implementing type is
 487     // reachable in rustdoc generated documentation
 488     if !did.is_local()
 489         && let Some(did) = for_.def_id(&cx.cache)
 490         && !is_directly_public(cx, did)
 491     {
 492         return;
 493     }
 494
 495     let document_hidden = cx.render_options.document_hidden;
 496     let predicates = tcx.explicit_predicates_of(did);
 497     let (trait_items, generics) = match impl_item {
 498         Some(impl_) => (
 499             impl_
 500                 .items
 501                 .iter()
 502                 .map(|item| tcx.hir().impl_item(item.id))
 503                 .filter(|item| {
 504                     // Filter out impl items whose corresponding trait item has `doc(hidden)`
 505                     // not to document such impl items.
 506                     // For inherent impls, we don't do any filtering, because that's already done in strip_hidden.rs.
 507
 508                     // When `--document-hidden-items` is passed, we don't
 509                     // do any filtering, too.
 510                     if document_hidden {
 511                         return true;
 512                     }
 513                     if let Some(associated_trait) = associated_trait {
 514                         let assoc_kind = match item.kind {
 515                             hir::ImplItemKind::Const(..) => ty::AssocKind::Const,
 516                             hir::ImplItemKind::Fn(..) => ty::AssocKind::Fn,
 517                             hir::ImplItemKind::Type(..) => ty::AssocKind::Type,
 518                         };
 519                         let trait_item = tcx
 520                             .associated_items(associated_trait.def_id)
 521                             .find_by_name_and_kind(
 522                                 tcx,
 523                                 item.ident,
 524                                 assoc_kind,
 525                                 associated_trait.def_id,
 526                             )
 527                             .unwrap(); // SAFETY: For all impl items there exists trait item that has the same name.
 528                         !tcx.is_doc_hidden(trait_item.def_id)
 529                     } else {
 530                         true
 531                     }
 532                 })
 533                 .map(|item| clean_impl_item(item, cx))
 534                 .collect::<Vec<_>>(),
 535             clean_generics(impl_.generics, cx),
 536         ),
 537         None => (
 538             tcx.associated_items(did)
 539                 .in_definition_order()
 540                 .filter(|item| !item.is_impl_trait_in_trait())
 541                 .filter(|item| {
 542                     // If this is a trait impl, filter out associated items whose corresponding item
 543                     // in the associated trait is marked `doc(hidden)`.
 544                     // If this is an inherent impl, filter out private associated items.
 545                     if let Some(associated_trait) = associated_trait {
 546                         let trait_item = tcx
 547                             .associated_items(associated_trait.def_id)
 548                             .find_by_name_and_kind(
 549                                 tcx,
 550                                 item.ident(tcx),
 551                                 item.kind,
 552                                 associated_trait.def_id,
 553                             )
 554                             .unwrap(); // corresponding associated item has to exist
 555                         document_hidden || !tcx.is_doc_hidden(trait_item.def_id)
 556                     } else {
 557                         item.visibility(tcx).is_public()
 558                     }
 559                 })
 560                 .map(|item| clean_middle_assoc_item(item, cx))
 561                 .collect::<Vec<_>>(),
 562             clean::enter_impl_trait(cx, |cx| {
 563                 clean_ty_generics(cx, tcx.generics_of(did), predicates)
 564             }),
 565         ),
 566     };
 567     let polarity = tcx.impl_polarity(did);
 568     let trait_ = associated_trait
 569         .map(|t| clean_trait_ref_with_bindings(cx, ty::Binder::dummy(t), ThinVec::new()));
 570     if trait_.as_ref().map(|t| t.def_id()) == tcx.lang_items().deref_trait() {
 571         super::build_deref_target_impls(cx, &trait_items, ret);
 572     }
 573
 574     // Return if the trait itself or any types of the generic parameters are doc(hidden).
 575     let mut stack: Vec<&Type> = vec![&for_];
 576
 577     if let Some(did) = trait_.as_ref().map(|t| t.def_id()) {
 578         if !document_hidden && tcx.is_doc_hidden(did) {
 579             return;
 580         }
 581     }
 582     if let Some(generics) = trait_.as_ref().and_then(|t| t.generics()) {
 583         stack.extend(generics);
 584     }
 585
 586     while let Some(ty) = stack.pop() {
 587         if let Some(did) = ty.def_id(&cx.cache)
 588             && !document_hidden
 589             && tcx.is_doc_hidden(did)
 590         {
 591             return;
 592         }
 593         if let Some(generics) = ty.generics() {
 594             stack.extend(generics);
 595         }
 596     }
 597
 598     if let Some(did) = trait_.as_ref().map(|t| t.def_id()) {
 599         cx.with_param_env(did, |cx| {
 600             record_extern_trait(cx, did);
 601         });
 602     }
 603
 604     let (merged_attrs, cfg) = merge_attrs(cx, load_attrs(cx, did), attrs);
 605     trace!("merged_attrs={merged_attrs:?}");
 606
 607     trace!(
 608         "build_impl: impl {:?} for {:?}",
 609         trait_.as_ref().map(|t| t.def_id()),
 610         for_.def_id(&cx.cache)
 611     );
 612     ret.push(clean::Item::from_def_id_and_attrs_and_parts(
 613         did,
 614         None,
 615         clean::ImplItem(Box::new(clean::Impl {
 616             unsafety: hir::Unsafety::Normal,
 617             generics,
 618             trait_,
 619             for_,
 620             items: trait_items,
 621             polarity,
 622             kind: if utils::has_doc_flag(tcx, did, sym::fake_variadic) {
 623                 ImplKind::FakeVariadic
 624             } else {
 625                 ImplKind::Normal
 626             },
 627         })),
 628         Box::new(merged_attrs),
 629         cfg,
 630     ));
 631 }
 632
 633 fn build_module(cx: &mut DocContext<'_>, did: DefId, visited: &mut DefIdSet) -> clean::Module {
 634     let items = build_module_items(cx, did, visited, &mut FxHashSet::default(), None, None);
 635
 636     let span = clean::Span::new(cx.tcx.def_span(did));
 637     clean::Module { items, span }
 638 }
 639
 640 fn build_module_items(
 641     cx: &mut DocContext<'_>,
 642     did: DefId,
 643     visited: &mut DefIdSet,
 644     inlined_names: &mut FxHashSet<(ItemType, Symbol)>,
 645     allowed_def_ids: Option<&DefIdSet>,
 646     attrs: Option<(&[ast::Attribute], Option<DefId>)>,
 647 ) -> Vec<clean::Item> {
 648     let mut items = Vec::new();
 649
 650     // If we're re-exporting a re-export it may actually re-export something in
 651     // two namespaces, so the target may be listed twice. Make sure we only
 652     // visit each node at most once.
 653     for item in cx.tcx.module_children(did).iter() {
 654         if item.vis.is_public() {
 655             let res = item.res.expect_non_local();
 656             if let Some(def_id) = res.opt_def_id()
 657                 && let Some(allowed_def_ids) = allowed_def_ids
 658                 && !allowed_def_ids.contains(&def_id)
 659             {
 660                 continue;
 661             }
 662             if let Some(def_id) = res.mod_def_id() {
 663                 // If we're inlining a glob import, it's possible to have
 664                 // two distinct modules with the same name. We don't want to
 665                 // inline it, or mark any of its contents as visited.
 666                 if did == def_id
 667                     || inlined_names.contains(&(ItemType::Module, item.ident.name))
 668                     || !visited.insert(def_id)
 669                 {
 670                     continue;
 671                 }
 672             }
 673             if let Res::PrimTy(p) = res {
 674                 // Primitive types can't be inlined so generate an import instead.
 675                 let prim_ty = clean::PrimitiveType::from(p);
 676                 items.push(clean::Item {
 677                     name: None,
 678                     attrs: Box::default(),
 679                     // We can use the item's `DefId` directly since the only information ever used
 680                     // from it is `DefId.krate`.
 681                     item_id: ItemId::DefId(did),
 682                     kind: Box::new(clean::ImportItem(clean::Import::new_simple(
 683                         item.ident.name,
 684                         clean::ImportSource {
 685                             path: clean::Path {
 686                                 res,
 687                                 segments: thin_vec![clean::PathSegment {
 688                                     name: prim_ty.as_sym(),
 689                                     args: clean::GenericArgs::AngleBracketed {
 690                                         args: Default::default(),
 691                                         bindings: ThinVec::new(),
 692                                     },
 693                                 }],
 694                             },
 695                             did: None,
 696                         },
 697                         true,
 698                     ))),
 699                     cfg: None,
 700                     inline_stmt_id: None,
 701                 });
 702             } else if let Some(i) = try_inline(cx, res, item.ident.name, attrs, visited) {
 703                 items.extend(i)
 704             }
 705         }
 706     }
 707
 708     items
 709 }
 710
 711 pub(crate) fn print_inlined_const(tcx: TyCtxt<'_>, did: DefId) -> String {
 712     if let Some(did) = did.as_local() {
 713         let hir_id = tcx.local_def_id_to_hir_id(did);
 714         rustc_hir_pretty::id_to_string(&tcx.hir(), hir_id)
 715     } else {
 716         tcx.rendered_const(did).clone()
 717     }
 718 }
 719
 720 fn build_const(cx: &mut DocContext<'_>, def_id: DefId) -> clean::Constant {
 721     let mut generics =
 722         clean_ty_generics(cx, cx.tcx.generics_of(def_id), cx.tcx.explicit_predicates_of(def_id));
 723     clean::simplify::move_bounds_to_generic_parameters(&mut generics);
 724
 725     clean::Constant {
 726         type_: Box::new(clean_middle_ty(
 727             ty::Binder::dummy(cx.tcx.type_of(def_id).instantiate_identity()),
 728             cx,
 729             Some(def_id),
 730             None,
 731         )),
 732         generics,
 733         kind: clean::ConstantKind::Extern { def_id },
 734     }
 735 }
 736
 737 fn build_static(cx: &mut DocContext<'_>, did: DefId, mutable: bool) -> clean::Static {
 738     clean::Static {
 739         type_: clean_middle_ty(
 740             ty::Binder::dummy(cx.tcx.type_of(did).instantiate_identity()),
 741             cx,
 742             Some(did),
 743             None,
 744         ),
 745         mutability: if mutable { Mutability::Mut } else { Mutability::Not },
 746         expr: None,
 747     }
 748 }
 749
 750 fn build_macro(
 751     cx: &mut DocContext<'_>,
 752     def_id: DefId,
 753     name: Symbol,
 754     import_def_id: Option<DefId>,
 755     macro_kind: MacroKind,
 756     is_doc_hidden: bool,
 757 ) -> clean::ItemKind {
 758     match CStore::from_tcx(cx.tcx).load_macro_untracked(def_id, cx.tcx) {
 759         LoadedMacro::MacroDef(item_def, _) => match macro_kind {
 760             MacroKind::Bang => {
 761                 if let ast::ItemKind::MacroDef(ref def) = item_def.kind {
 762                     let vis = cx.tcx.visibility(import_def_id.unwrap_or(def_id));
 763                     clean::MacroItem(clean::Macro {
 764                         source: utils::display_macro_source(
 765                             cx,
 766                             name,
 767                             def,
 768                             def_id,
 769                             vis,
 770                             is_doc_hidden,
 771                         ),
 772                     })
 773                 } else {
 774                     unreachable!()
 775                 }
 776             }
 777             MacroKind::Derive | MacroKind::Attr => {
 778                 clean::ProcMacroItem(clean::ProcMacro { kind: macro_kind, helpers: Vec::new() })
 779             }
 780         },
 781         LoadedMacro::ProcMacro(ext) => clean::ProcMacroItem(clean::ProcMacro {
 782             kind: ext.macro_kind(),
 783             helpers: ext.helper_attrs,
 784         }),
 785     }
 786 }
 787
 788 /// A trait's generics clause actually contains all of the predicates for all of
 789 /// its associated types as well. We specifically move these clauses to the
 790 /// associated types instead when displaying, so when we're generating the
 791 /// generics for the trait itself we need to be sure to remove them.
 792 /// We also need to remove the implied "recursive" Self: Trait bound.
 793 ///
 794 /// The inverse of this filtering logic can be found in the `Clean`
 795 /// implementation for `AssociatedType`
 796 fn filter_non_trait_generics(trait_did: DefId, mut g: clean::Generics) -> clean::Generics {
 797     for pred in &mut g.where_predicates {
 798         match *pred {
 799             clean::WherePredicate::BoundPredicate {
 800                 ty: clean::Generic(ref s),
 801                 ref mut bounds,
 802                 ..
 803             } if *s == kw::SelfUpper => {
 804                 bounds.retain(|bound| match bound {
 805                     clean::GenericBound::TraitBound(clean::PolyTrait { trait_, .. }, _) => {
 806                         trait_.def_id() != trait_did
 807                     }
 808                     _ => true,
 809                 });
 810             }
 811             _ => {}
 812         }
 813     }
 814
 815     g.where_predicates.retain(|pred| match pred {
 816         clean::WherePredicate::BoundPredicate {
 817             ty:
 818                 clean::QPath(box clean::QPathData {
 819                     self_type: clean::Generic(ref s),
 820                     trait_: Some(trait_),
 821                     ..
 822                 }),
 823             bounds,
 824             ..
 825         } => !(bounds.is_empty() || *s == kw::SelfUpper && trait_.def_id() == trait_did),
 826         _ => true,
 827     });
 828     g
 829 }
 830
 831 /// Supertrait bounds for a trait are also listed in the generics coming from
 832 /// the metadata for a crate, so we want to separate those out and create a new
 833 /// list of explicit supertrait bounds to render nicely.
 834 fn separate_supertrait_bounds(
 835     mut g: clean::Generics,
 836 ) -> (clean::Generics, Vec<clean::GenericBound>) {
 837     let mut ty_bounds = Vec::new();
 838     g.where_predicates.retain(|pred| match *pred {
 839         clean::WherePredicate::BoundPredicate { ty: clean::Generic(ref s), ref bounds, .. }
 840             if *s == kw::SelfUpper =>
 841         {
 842             ty_bounds.extend(bounds.iter().cloned());
 843             false
 844         }
 845         _ => true,
 846     });
 847     (g, ty_bounds)
 848 }
 849
 850 pub(crate) fn record_extern_trait(cx: &mut DocContext<'_>, did: DefId) {
 851     if did.is_local() {
 852         return;
 853     }
 854
 855     {
 856         if cx.external_traits.borrow().contains_key(&did) || cx.active_extern_traits.contains(&did)
 857         {
 858             return;
 859         }
 860     }
 861
 862     {
 863         cx.active_extern_traits.insert(did);
 864     }
 865
 866     debug!("record_extern_trait: {did:?}");
 867     let trait_ = build_external_trait(cx, did);
 868
 869     cx.external_traits.borrow_mut().insert(did, trait_);
 870     cx.active_extern_traits.remove(&did);
 871 }