src/librustdoc/clean/mod.rs

   1 //! This module contains the "cleaned" pieces of the AST, and the functions
   2 //! that clean them.
   3
   4 mod auto_trait;
   5 mod blanket_impl;
   6 pub mod cfg;
   7 pub mod inline;
   8 mod simplify;
   9 pub mod types;
  10 pub mod utils;
  11
  12 use rustc_ast::ast::{self, Ident};
  13 use rustc_attr as attr;
  14 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
  15 use rustc_hir as hir;
  16 use rustc_hir::def::{CtorKind, DefKind, Res};
  17 use rustc_hir::def_id::{CrateNum, DefId, CRATE_DEF_INDEX};
  18 use rustc_index::vec::{Idx, IndexVec};
  19 use rustc_infer::infer::region_constraints::{Constraint, RegionConstraintData};
  20 use rustc_middle::middle::lang_items;
  21 use rustc_middle::middle::resolve_lifetime as rl;
  22 use rustc_middle::middle::stability;
  23 use rustc_middle::ty::fold::TypeFolder;
  24 use rustc_middle::ty::subst::InternalSubsts;
  25 use rustc_middle::ty::{self, AdtKind, Lift, Ty, TyCtxt};
  26 use rustc_mir::const_eval::is_min_const_fn;
  27 use rustc_span::hygiene::MacroKind;
  28 use rustc_span::symbol::{kw, sym};
  29 use rustc_span::{self, Pos};
  30 use rustc_typeck::hir_ty_to_ty;
  31
  32 use std::collections::hash_map::Entry;
  33 use std::default::Default;
  34 use std::hash::Hash;
  35 use std::rc::Rc;
  36 use std::u32;
  37 use std::{mem, vec};
  38
  39 use crate::core::{self, DocContext, ImplTraitParam};
  40 use crate::doctree;
  41
  42 use utils::*;
  43
  44 pub use utils::{get_auto_trait_and_blanket_impls, krate, register_res};
  45
  46 pub use self::types::FnRetTy::*;
  47 pub use self::types::ItemEnum::*;
  48 pub use self::types::SelfTy::*;
  49 pub use self::types::Type::*;
  50 pub use self::types::Visibility::{Inherited, Public};
  51 pub use self::types::*;
  52
  53 const FN_OUTPUT_NAME: &str = "Output";
  54
  55 pub trait Clean<T> {
  56     fn clean(&self, cx: &DocContext<'_>) -> T;
  57 }
  58
  59 impl<T: Clean<U>, U> Clean<Vec<U>> for [T] {
  60     fn clean(&self, cx: &DocContext<'_>) -> Vec<U> {
  61         self.iter().map(|x| x.clean(cx)).collect()
  62     }
  63 }
  64
  65 impl<T: Clean<U>, U, V: Idx> Clean<IndexVec<V, U>> for IndexVec<V, T> {
  66     fn clean(&self, cx: &DocContext<'_>) -> IndexVec<V, U> {
  67         self.iter().map(|x| x.clean(cx)).collect()
  68     }
  69 }
  70
  71 impl<T: Clean<U>, U> Clean<U> for &T {
  72     fn clean(&self, cx: &DocContext<'_>) -> U {
  73         (**self).clean(cx)
  74     }
  75 }
  76
  77 impl<T: Clean<U>, U> Clean<U> for Rc<T> {
  78     fn clean(&self, cx: &DocContext<'_>) -> U {
  79         (**self).clean(cx)
  80     }
  81 }
  82
  83 impl<T: Clean<U>, U> Clean<Option<U>> for Option<T> {
  84     fn clean(&self, cx: &DocContext<'_>) -> Option<U> {
  85         self.as_ref().map(|v| v.clean(cx))
  86     }
  87 }
  88
  89 impl<T, U> Clean<U> for ty::Binder<T>
  90 where
  91     T: Clean<U>,
  92 {
  93     fn clean(&self, cx: &DocContext<'_>) -> U {
  94         self.skip_binder().clean(cx)
  95     }
  96 }
  97
  98 impl Clean<ExternalCrate> for CrateNum {
  99     fn clean(&self, cx: &DocContext<'_>) -> ExternalCrate {
 100         let root = DefId { krate: *self, index: CRATE_DEF_INDEX };
 101         let krate_span = cx.tcx.def_span(root);
 102         let krate_src = cx.sess().source_map().span_to_filename(krate_span);
 103
 104         // Collect all inner modules which are tagged as implementations of
 105         // primitives.
 106         //
 107         // Note that this loop only searches the top-level items of the crate,
 108         // and this is intentional. If we were to search the entire crate for an
 109         // item tagged with `#[doc(primitive)]` then we would also have to
 110         // search the entirety of external modules for items tagged
 111         // `#[doc(primitive)]`, which is a pretty inefficient process (decoding
 112         // all that metadata unconditionally).
 113         //
 114         // In order to keep the metadata load under control, the
 115         // `#[doc(primitive)]` feature is explicitly designed to only allow the
 116         // primitive tags to show up as the top level items in a crate.
 117         //
 118         // Also note that this does not attempt to deal with modules tagged
 119         // duplicately for the same primitive. This is handled later on when
 120         // rendering by delegating everything to a hash map.
 121         let as_primitive = |res: Res| {
 122             if let Res::Def(DefKind::Mod, def_id) = res {
 123                 let attrs = cx.tcx.get_attrs(def_id).clean(cx);
 124                 let mut prim = None;
 125                 for attr in attrs.lists(sym::doc) {
 126                     if let Some(v) = attr.value_str() {
 127                         if attr.check_name(sym::primitive) {
 128                             prim = PrimitiveType::from_str(&v.as_str());
 129                             if prim.is_some() {
 130                                 break;
 131                             }
 132                             // FIXME: should warn on unknown primitives?
 133                         }
 134                     }
 135                 }
 136                 return prim.map(|p| (def_id, p, attrs));
 137             }
 138             None
 139         };
 140         let primitives = if root.is_local() {
 141             cx.tcx
 142                 .hir()
 143                 .krate()
 144                 .item
 145                 .module
 146                 .item_ids
 147                 .iter()
 148                 .filter_map(|&id| {
 149                     let item = cx.tcx.hir().expect_item(id.id);
 150                     match item.kind {
 151                         hir::ItemKind::Mod(_) => {
 152                             as_primitive(Res::Def(DefKind::Mod, cx.tcx.hir().local_def_id(id.id)))
 153                         }
 154                         hir::ItemKind::Use(ref path, hir::UseKind::Single)
 155                             if item.vis.node.is_pub() =>
 156                         {
 157                             as_primitive(path.res).map(|(_, prim, attrs)| {
 158                                 // Pretend the primitive is local.
 159                                 (cx.tcx.hir().local_def_id(id.id), prim, attrs)
 160                             })
 161                         }
 162                         _ => None,
 163                     }
 164                 })
 165                 .collect()
 166         } else {
 167             cx.tcx
 168                 .item_children(root)
 169                 .iter()
 170                 .map(|item| item.res)
 171                 .filter_map(as_primitive)
 172                 .collect()
 173         };
 174
 175         let as_keyword = |res: Res| {
 176             if let Res::Def(DefKind::Mod, def_id) = res {
 177                 let attrs = cx.tcx.get_attrs(def_id).clean(cx);
 178                 let mut keyword = None;
 179                 for attr in attrs.lists(sym::doc) {
 180                     if let Some(v) = attr.value_str() {
 181                         if attr.check_name(sym::keyword) {
 182                             if v.is_doc_keyword() {
 183                                 keyword = Some(v.to_string());
 184                                 break;
 185                             }
 186                             // FIXME: should warn on unknown keywords?
 187                         }
 188                     }
 189                 }
 190                 return keyword.map(|p| (def_id, p, attrs));
 191             }
 192             None
 193         };
 194         let keywords = if root.is_local() {
 195             cx.tcx
 196                 .hir()
 197                 .krate()
 198                 .item
 199                 .module
 200                 .item_ids
 201                 .iter()
 202                 .filter_map(|&id| {
 203                     let item = cx.tcx.hir().expect_item(id.id);
 204                     match item.kind {
 205                         hir::ItemKind::Mod(_) => {
 206                             as_keyword(Res::Def(DefKind::Mod, cx.tcx.hir().local_def_id(id.id)))
 207                         }
 208                         hir::ItemKind::Use(ref path, hir::UseKind::Single)
 209                             if item.vis.node.is_pub() =>
 210                         {
 211                             as_keyword(path.res).map(|(_, prim, attrs)| {
 212                                 (cx.tcx.hir().local_def_id(id.id), prim, attrs)
 213                             })
 214                         }
 215                         _ => None,
 216                     }
 217                 })
 218                 .collect()
 219         } else {
 220             cx.tcx.item_children(root).iter().map(|item| item.res).filter_map(as_keyword).collect()
 221         };
 222
 223         ExternalCrate {
 224             name: cx.tcx.crate_name(*self).to_string(),
 225             src: krate_src,
 226             attrs: cx.tcx.get_attrs(root).clean(cx),
 227             primitives,
 228             keywords,
 229         }
 230     }
 231 }
 232
 233 impl Clean<Item> for doctree::Module<'_> {
 234     fn clean(&self, cx: &DocContext<'_>) -> Item {
 235         let name = if self.name.is_some() {
 236             self.name.expect("No name provided").clean(cx)
 237         } else {
 238             String::new()
 239         };
 240
 241         // maintain a stack of mod ids, for doc comment path resolution
 242         // but we also need to resolve the module's own docs based on whether its docs were written
 243         // inside or outside the module, so check for that
 244         let attrs = self.attrs.clean(cx);
 245
 246         let mut items: Vec<Item> = vec![];
 247         items.extend(self.extern_crates.iter().flat_map(|x| x.clean(cx)));
 248         items.extend(self.imports.iter().flat_map(|x| x.clean(cx)));
 249         items.extend(self.structs.iter().map(|x| x.clean(cx)));
 250         items.extend(self.unions.iter().map(|x| x.clean(cx)));
 251         items.extend(self.enums.iter().map(|x| x.clean(cx)));
 252         items.extend(self.fns.iter().map(|x| x.clean(cx)));
 253         items.extend(self.foreigns.iter().map(|x| x.clean(cx)));
 254         items.extend(self.mods.iter().map(|x| x.clean(cx)));
 255         items.extend(self.typedefs.iter().map(|x| x.clean(cx)));
 256         items.extend(self.opaque_tys.iter().map(|x| x.clean(cx)));
 257         items.extend(self.statics.iter().map(|x| x.clean(cx)));
 258         items.extend(self.constants.iter().map(|x| x.clean(cx)));
 259         items.extend(self.traits.iter().map(|x| x.clean(cx)));
 260         items.extend(self.impls.iter().flat_map(|x| x.clean(cx)));
 261         items.extend(self.macros.iter().map(|x| x.clean(cx)));
 262         items.extend(self.proc_macros.iter().map(|x| x.clean(cx)));
 263         items.extend(self.trait_aliases.iter().map(|x| x.clean(cx)));
 264
 265         // determine if we should display the inner contents or
 266         // the outer `mod` item for the source code.
 267         let whence = {
 268             let sm = cx.sess().source_map();
 269             let outer = sm.lookup_char_pos(self.where_outer.lo());
 270             let inner = sm.lookup_char_pos(self.where_inner.lo());
 271             if outer.file.start_pos == inner.file.start_pos {
 272                 // mod foo { ... }
 273                 self.where_outer
 274             } else {
 275                 // mod foo; (and a separate SourceFile for the contents)
 276                 self.where_inner
 277             }
 278         };
 279
 280         Item {
 281             name: Some(name),
 282             attrs,
 283             source: whence.clean(cx),
 284             visibility: self.vis.clean(cx),
 285             stability: cx.stability(self.id).clean(cx),
 286             deprecation: cx.deprecation(self.id).clean(cx),
 287             def_id: cx.tcx.hir().local_def_id(self.id),
 288             inner: ModuleItem(Module { is_crate: self.is_crate, items }),
 289         }
 290     }
 291 }
 292
 293 impl Clean<Attributes> for [ast::Attribute] {
 294     fn clean(&self, cx: &DocContext<'_>) -> Attributes {
 295         Attributes::from_ast(cx.sess().diagnostic(), self)
 296     }
 297 }
 298
 299 impl Clean<GenericBound> for hir::GenericBound<'_> {
 300     fn clean(&self, cx: &DocContext<'_>) -> GenericBound {
 301         match *self {
 302             hir::GenericBound::Outlives(lt) => GenericBound::Outlives(lt.clean(cx)),
 303             hir::GenericBound::Trait(ref t, modifier) => {
 304                 GenericBound::TraitBound(t.clean(cx), modifier)
 305             }
 306         }
 307     }
 308 }
 309
 310 impl<'a, 'tcx> Clean<GenericBound> for (&'a ty::TraitRef<'tcx>, Vec<TypeBinding>) {
 311     fn clean(&self, cx: &DocContext<'_>) -> GenericBound {
 312         let (trait_ref, ref bounds) = *self;
 313         inline::record_extern_fqn(cx, trait_ref.def_id, TypeKind::Trait);
 314         let path = external_path(
 315             cx,
 316             cx.tcx.item_name(trait_ref.def_id),
 317             Some(trait_ref.def_id),
 318             true,
 319             bounds.clone(),
 320             trait_ref.substs,
 321         );
 322
 323         debug!("ty::TraitRef\n  subst: {:?}\n", trait_ref.substs);
 324
 325         // collect any late bound regions
 326         let mut late_bounds = vec![];
 327         for ty_s in trait_ref.input_types().skip(1) {
 328             if let ty::Tuple(ts) = ty_s.kind {
 329                 for &ty_s in ts {
 330                     if let ty::Ref(ref reg, _, _) = ty_s.expect_ty().kind {
 331                         if let &ty::RegionKind::ReLateBound(..) = *reg {
 332                             debug!("  hit an ReLateBound {:?}", reg);
 333                             if let Some(Lifetime(name)) = reg.clean(cx) {
 334                                 late_bounds.push(GenericParamDef {
 335                                     name,
 336                                     kind: GenericParamDefKind::Lifetime,
 337                                 });
 338                             }
 339                         }
 340                     }
 341                 }
 342             }
 343         }
 344
 345         GenericBound::TraitBound(
 346             PolyTrait {
 347                 trait_: ResolvedPath {
 348                     path,
 349                     param_names: None,
 350                     did: trait_ref.def_id,
 351                     is_generic: false,
 352                 },
 353                 generic_params: late_bounds,
 354             },
 355             hir::TraitBoundModifier::None,
 356         )
 357     }
 358 }
 359
 360 impl<'tcx> Clean<GenericBound> for ty::TraitRef<'tcx> {
 361     fn clean(&self, cx: &DocContext<'_>) -> GenericBound {
 362         (self, vec![]).clean(cx)
 363     }
 364 }
 365
 366 impl<'tcx> Clean<Option<Vec<GenericBound>>> for InternalSubsts<'tcx> {
 367     fn clean(&self, cx: &DocContext<'_>) -> Option<Vec<GenericBound>> {
 368         let mut v = Vec::new();
 369         v.extend(self.regions().filter_map(|r| r.clean(cx)).map(GenericBound::Outlives));
 370         v.extend(self.types().map(|t| {
 371             GenericBound::TraitBound(
 372                 PolyTrait { trait_: t.clean(cx), generic_params: Vec::new() },
 373                 hir::TraitBoundModifier::None,
 374             )
 375         }));
 376         if !v.is_empty() { Some(v) } else { None }
 377     }
 378 }
 379
 380 impl Clean<Lifetime> for hir::Lifetime {
 381     fn clean(&self, cx: &DocContext<'_>) -> Lifetime {
 382         if self.hir_id != hir::DUMMY_HIR_ID {
 383             let def = cx.tcx.named_region(self.hir_id);
 384             match def {
 385                 Some(rl::Region::EarlyBound(_, node_id, _))
 386                 | Some(rl::Region::LateBound(_, node_id, _))
 387                 | Some(rl::Region::Free(_, node_id)) => {
 388                     if let Some(lt) = cx.lt_substs.borrow().get(&node_id).cloned() {
 389                         return lt;
 390                     }
 391                 }
 392                 _ => {}
 393             }
 394         }
 395         Lifetime(self.name.ident().to_string())
 396     }
 397 }
 398
 399 impl Clean<Lifetime> for hir::GenericParam<'_> {
 400     fn clean(&self, _: &DocContext<'_>) -> Lifetime {
 401         match self.kind {
 402             hir::GenericParamKind::Lifetime { .. } => {
 403                 if !self.bounds.is_empty() {
 404                     let mut bounds = self.bounds.iter().map(|bound| match bound {
 405                         hir::GenericBound::Outlives(lt) => lt,
 406                         _ => panic!(),
 407                     });
 408                     let name = bounds.next().expect("no more bounds").name.ident();
 409                     let mut s = format!("{}: {}", self.name.ident(), name);
 410                     for bound in bounds {
 411                         s.push_str(&format!(" + {}", bound.name.ident()));
 412                     }
 413                     Lifetime(s)
 414                 } else {
 415                     Lifetime(self.name.ident().to_string())
 416                 }
 417             }
 418             _ => panic!(),
 419         }
 420     }
 421 }
 422
 423 impl Clean<Constant> for hir::ConstArg {
 424     fn clean(&self, cx: &DocContext<'_>) -> Constant {
 425         Constant {
 426             type_: cx.tcx.type_of(cx.tcx.hir().body_owner_def_id(self.value.body)).clean(cx),
 427             expr: print_const_expr(cx, self.value.body),
 428             value: None,
 429             is_literal: is_literal_expr(cx, self.value.body.hir_id),
 430         }
 431     }
 432 }
 433
 434 impl Clean<Lifetime> for ty::GenericParamDef {
 435     fn clean(&self, _cx: &DocContext<'_>) -> Lifetime {
 436         Lifetime(self.name.to_string())
 437     }
 438 }
 439
 440 impl Clean<Option<Lifetime>> for ty::RegionKind {
 441     fn clean(&self, cx: &DocContext<'_>) -> Option<Lifetime> {
 442         match *self {
 443             ty::ReStatic => Some(Lifetime::statik()),
 444             ty::ReLateBound(_, ty::BrNamed(_, name)) => Some(Lifetime(name.to_string())),
 445             ty::ReEarlyBound(ref data) => Some(Lifetime(data.name.clean(cx))),
 446
 447             ty::ReLateBound(..)
 448             | ty::ReFree(..)
 449             | ty::ReScope(..)
 450             | ty::ReVar(..)
 451             | ty::RePlaceholder(..)
 452             | ty::ReEmpty(_)
 453             | ty::ReErased => {
 454                 debug!("cannot clean region {:?}", self);
 455                 None
 456             }
 457         }
 458     }
 459 }
 460
 461 impl Clean<WherePredicate> for hir::WherePredicate<'_> {
 462     fn clean(&self, cx: &DocContext<'_>) -> WherePredicate {
 463         match *self {
 464             hir::WherePredicate::BoundPredicate(ref wbp) => WherePredicate::BoundPredicate {
 465                 ty: wbp.bounded_ty.clean(cx),
 466                 bounds: wbp.bounds.clean(cx),
 467             },
 468
 469             hir::WherePredicate::RegionPredicate(ref wrp) => WherePredicate::RegionPredicate {
 470                 lifetime: wrp.lifetime.clean(cx),
 471                 bounds: wrp.bounds.clean(cx),
 472             },
 473
 474             hir::WherePredicate::EqPredicate(ref wrp) => {
 475                 WherePredicate::EqPredicate { lhs: wrp.lhs_ty.clean(cx), rhs: wrp.rhs_ty.clean(cx) }
 476             }
 477         }
 478     }
 479 }
 480
 481 impl<'a> Clean<Option<WherePredicate>> for ty::Predicate<'a> {
 482     fn clean(&self, cx: &DocContext<'_>) -> Option<WherePredicate> {
 483         use rustc_middle::ty::Predicate;
 484
 485         match *self {
 486             Predicate::Trait(ref pred, _) => Some(pred.clean(cx)),
 487             Predicate::Subtype(ref pred) => Some(pred.clean(cx)),
 488             Predicate::RegionOutlives(ref pred) => pred.clean(cx),
 489             Predicate::TypeOutlives(ref pred) => pred.clean(cx),
 490             Predicate::Projection(ref pred) => Some(pred.clean(cx)),
 491
 492             Predicate::WellFormed(..)
 493             | Predicate::ObjectSafe(..)
 494             | Predicate::ClosureKind(..)
 495             | Predicate::ConstEvaluatable(..) => panic!("not user writable"),
 496         }
 497     }
 498 }
 499
 500 impl<'a> Clean<WherePredicate> for ty::TraitPredicate<'a> {
 501     fn clean(&self, cx: &DocContext<'_>) -> WherePredicate {
 502         WherePredicate::BoundPredicate {
 503             ty: self.trait_ref.self_ty().clean(cx),
 504             bounds: vec![self.trait_ref.clean(cx)],
 505         }
 506     }
 507 }
 508
 509 impl<'tcx> Clean<WherePredicate> for ty::SubtypePredicate<'tcx> {
 510     fn clean(&self, _cx: &DocContext<'_>) -> WherePredicate {
 511         panic!(
 512             "subtype predicates are an internal rustc artifact \
 513                 and should not be seen by rustdoc"
 514         )
 515     }
 516 }
 517
 518 impl<'tcx> Clean<Option<WherePredicate>>
 519     for ty::OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>>
 520 {
 521     fn clean(&self, cx: &DocContext<'_>) -> Option<WherePredicate> {
 522         let ty::OutlivesPredicate(ref a, ref b) = *self;
 523
 524         if let (ty::ReEmpty(_), ty::ReEmpty(_)) = (a, b) {
 525             return None;
 526         }
 527
 528         Some(WherePredicate::RegionPredicate {
 529             lifetime: a.clean(cx).expect("failed to clean lifetime"),
 530             bounds: vec![GenericBound::Outlives(b.clean(cx).expect("failed to clean bounds"))],
 531         })
 532     }
 533 }
 534
 535 impl<'tcx> Clean<Option<WherePredicate>> for ty::OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>> {
 536     fn clean(&self, cx: &DocContext<'_>) -> Option<WherePredicate> {
 537         let ty::OutlivesPredicate(ref ty, ref lt) = *self;
 538
 539         if let ty::ReEmpty(_) = lt {
 540             return None;
 541         }
 542
 543         Some(WherePredicate::BoundPredicate {
 544             ty: ty.clean(cx),
 545             bounds: vec![GenericBound::Outlives(lt.clean(cx).expect("failed to clean lifetimes"))],
 546         })
 547     }
 548 }
 549
 550 impl<'tcx> Clean<WherePredicate> for ty::ProjectionPredicate<'tcx> {
 551     fn clean(&self, cx: &DocContext<'_>) -> WherePredicate {
 552         WherePredicate::EqPredicate { lhs: self.projection_ty.clean(cx), rhs: self.ty.clean(cx) }
 553     }
 554 }
 555
 556 impl<'tcx> Clean<Type> for ty::ProjectionTy<'tcx> {
 557     fn clean(&self, cx: &DocContext<'_>) -> Type {
 558         let lifted = self.lift_to_tcx(cx.tcx).unwrap();
 559         let trait_ = match lifted.trait_ref(cx.tcx).clean(cx) {
 560             GenericBound::TraitBound(t, _) => t.trait_,
 561             GenericBound::Outlives(_) => panic!("cleaning a trait got a lifetime"),
 562         };
 563         Type::QPath {
 564             name: cx.tcx.associated_item(self.item_def_id).ident.name.clean(cx),
 565             self_type: box self.self_ty().clean(cx),
 566             trait_: box trait_,
 567         }
 568     }
 569 }
 570
 571 impl Clean<GenericParamDef> for ty::GenericParamDef {
 572     fn clean(&self, cx: &DocContext<'_>) -> GenericParamDef {
 573         let (name, kind) = match self.kind {
 574             ty::GenericParamDefKind::Lifetime => {
 575                 (self.name.to_string(), GenericParamDefKind::Lifetime)
 576             }
 577             ty::GenericParamDefKind::Type { has_default, synthetic, .. } => {
 578                 let default =
 579                     if has_default { Some(cx.tcx.type_of(self.def_id).clean(cx)) } else { None };
 580                 (
 581                     self.name.clean(cx),
 582                     GenericParamDefKind::Type {
 583                         did: self.def_id,
 584                         bounds: vec![], // These are filled in from the where-clauses.
 585                         default,
 586                         synthetic,
 587                     },
 588                 )
 589             }
 590             ty::GenericParamDefKind::Const { .. } => (
 591                 self.name.clean(cx),
 592                 GenericParamDefKind::Const {
 593                     did: self.def_id,
 594                     ty: cx.tcx.type_of(self.def_id).clean(cx),
 595                 },
 596             ),
 597         };
 598
 599         GenericParamDef { name, kind }
 600     }
 601 }
 602
 603 impl Clean<GenericParamDef> for hir::GenericParam<'_> {
 604     fn clean(&self, cx: &DocContext<'_>) -> GenericParamDef {
 605         let (name, kind) = match self.kind {
 606             hir::GenericParamKind::Lifetime { .. } => {
 607                 let name = if !self.bounds.is_empty() {
 608                     let mut bounds = self.bounds.iter().map(|bound| match bound {
 609                         hir::GenericBound::Outlives(lt) => lt,
 610                         _ => panic!(),
 611                     });
 612                     let name = bounds.next().expect("no more bounds").name.ident();
 613                     let mut s = format!("{}: {}", self.name.ident(), name);
 614                     for bound in bounds {
 615                         s.push_str(&format!(" + {}", bound.name.ident()));
 616                     }
 617                     s
 618                 } else {
 619                     self.name.ident().to_string()
 620                 };
 621                 (name, GenericParamDefKind::Lifetime)
 622             }
 623             hir::GenericParamKind::Type { ref default, synthetic } => (
 624                 self.name.ident().name.clean(cx),
 625                 GenericParamDefKind::Type {
 626                     did: cx.tcx.hir().local_def_id(self.hir_id),
 627                     bounds: self.bounds.clean(cx),
 628                     default: default.clean(cx),
 629                     synthetic,
 630                 },
 631             ),
 632             hir::GenericParamKind::Const { ref ty } => (
 633                 self.name.ident().name.clean(cx),
 634                 GenericParamDefKind::Const {
 635                     did: cx.tcx.hir().local_def_id(self.hir_id),
 636                     ty: ty.clean(cx),
 637                 },
 638             ),
 639         };
 640
 641         GenericParamDef { name, kind }
 642     }
 643 }
 644
 645 impl Clean<Generics> for hir::Generics<'_> {
 646     fn clean(&self, cx: &DocContext<'_>) -> Generics {
 647         // Synthetic type-parameters are inserted after normal ones.
 648         // In order for normal parameters to be able to refer to synthetic ones,
 649         // scans them first.
 650         fn is_impl_trait(param: &hir::GenericParam<'_>) -> bool {
 651             match param.kind {
 652                 hir::GenericParamKind::Type { synthetic, .. } => {
 653                     synthetic == Some(hir::SyntheticTyParamKind::ImplTrait)
 654                 }
 655                 _ => false,
 656             }
 657         }
 658         let impl_trait_params = self
 659             .params
 660             .iter()
 661             .filter(|param| is_impl_trait(param))
 662             .map(|param| {
 663                 let param: GenericParamDef = param.clean(cx);
 664                 match param.kind {
 665                     GenericParamDefKind::Lifetime => unreachable!(),
 666                     GenericParamDefKind::Type { did, ref bounds, .. } => {
 667                         cx.impl_trait_bounds.borrow_mut().insert(did.into(), bounds.clone());
 668                     }
 669                     GenericParamDefKind::Const { .. } => unreachable!(),
 670                 }
 671                 param
 672             })
 673             .collect::<Vec<_>>();
 674
 675         let mut params = Vec::with_capacity(self.params.len());
 676         for p in self.params.iter().filter(|p| !is_impl_trait(p)) {
 677             let p = p.clean(cx);
 678             params.push(p);
 679         }
 680         params.extend(impl_trait_params);
 681
 682         let mut generics =
 683             Generics { params, where_predicates: self.where_clause.predicates.clean(cx) };
 684
 685         // Some duplicates are generated for ?Sized bounds between type params and where
 686         // predicates. The point in here is to move the bounds definitions from type params
 687         // to where predicates when such cases occur.
 688         for where_pred in &mut generics.where_predicates {
 689             match *where_pred {
 690                 WherePredicate::BoundPredicate { ty: Generic(ref name), ref mut bounds } => {
 691                     if bounds.is_empty() {
 692                         for param in &mut generics.params {
 693                             match param.kind {
 694                                 GenericParamDefKind::Lifetime => {}
 695                                 GenericParamDefKind::Type { bounds: ref mut ty_bounds, .. } => {
 696                                     if &param.name == name {
 697                                         mem::swap(bounds, ty_bounds);
 698                                         break;
 699                                     }
 700                                 }
 701                                 GenericParamDefKind::Const { .. } => {}
 702                             }
 703                         }
 704                     }
 705                 }
 706                 _ => continue,
 707             }
 708         }
 709         generics
 710     }
 711 }
 712
 713 impl<'a, 'tcx> Clean<Generics> for (&'a ty::Generics, ty::GenericPredicates<'tcx>) {
 714     fn clean(&self, cx: &DocContext<'_>) -> Generics {
 715         use self::WherePredicate as WP;
 716         use std::collections::BTreeMap;
 717
 718         let (gens, preds) = *self;
 719
 720         // Don't populate `cx.impl_trait_bounds` before `clean`ning `where` clauses,
 721         // since `Clean for ty::Predicate` would consume them.
 722         let mut impl_trait = BTreeMap::<ImplTraitParam, Vec<GenericBound>>::default();
 723
 724         // Bounds in the type_params and lifetimes fields are repeated in the
 725         // predicates field (see rustc_typeck::collect::ty_generics), so remove
 726         // them.
 727         let stripped_typarams = gens
 728             .params
 729             .iter()
 730             .filter_map(|param| match param.kind {
 731                 ty::GenericParamDefKind::Lifetime => None,
 732                 ty::GenericParamDefKind::Type { synthetic, .. } => {
 733                     if param.name == kw::SelfUpper {
 734                         assert_eq!(param.index, 0);
 735                         return None;
 736                     }
 737                     if synthetic == Some(hir::SyntheticTyParamKind::ImplTrait) {
 738                         impl_trait.insert(param.index.into(), vec![]);
 739                         return None;
 740                     }
 741                     Some(param.clean(cx))
 742                 }
 743                 ty::GenericParamDefKind::Const { .. } => None,
 744             })
 745             .collect::<Vec<GenericParamDef>>();
 746
 747         // param index -> [(DefId of trait, associated type name, type)]
 748         let mut impl_trait_proj = FxHashMap::<u32, Vec<(DefId, String, Ty<'tcx>)>>::default();
 749
 750         let where_predicates = preds
 751             .predicates
 752             .iter()
 753             .flat_map(|(p, _)| {
 754                 let mut projection = None;
 755                 let param_idx = (|| {
 756                     if let Some(trait_ref) = p.to_opt_poly_trait_ref() {
 757                         if let ty::Param(param) = trait_ref.self_ty().kind {
 758                             return Some(param.index);
 759                         }
 760                     } else if let Some(outlives) = p.to_opt_type_outlives() {
 761                         if let ty::Param(param) = outlives.skip_binder().0.kind {
 762                             return Some(param.index);
 763                         }
 764                     } else if let ty::Predicate::Projection(p) = p {
 765                         if let ty::Param(param) = p.skip_binder().projection_ty.self_ty().kind {
 766                             projection = Some(p);
 767                             return Some(param.index);
 768                         }
 769                     }
 770
 771                     None
 772                 })();
 773
 774                 if let Some(param_idx) = param_idx {
 775                     if let Some(b) = impl_trait.get_mut(&param_idx.into()) {
 776                         let p = p.clean(cx)?;
 777
 778                         b.extend(
 779                             p.get_bounds()
 780                                 .into_iter()
 781                                 .flatten()
 782                                 .cloned()
 783                                 .filter(|b| !b.is_sized_bound(cx)),
 784                         );
 785
 786                         let proj = projection
 787                             .map(|p| (p.skip_binder().projection_ty.clean(cx), p.skip_binder().ty));
 788                         if let Some(((_, trait_did, name), rhs)) =
 789                             proj.as_ref().and_then(|(lhs, rhs)| Some((lhs.projection()?, rhs)))
 790                         {
 791                             impl_trait_proj.entry(param_idx).or_default().push((
 792                                 trait_did,
 793                                 name.to_string(),
 794                                 rhs,
 795                             ));
 796                         }
 797
 798                         return None;
 799                     }
 800                 }
 801
 802                 Some(p)
 803             })
 804             .collect::<Vec<_>>();
 805
 806         for (param, mut bounds) in impl_trait {
 807             // Move trait bounds to the front.
 808             bounds.sort_by_key(|b| if let GenericBound::TraitBound(..) = b { false } else { true });
 809
 810             if let crate::core::ImplTraitParam::ParamIndex(idx) = param {
 811                 if let Some(proj) = impl_trait_proj.remove(&idx) {
 812                     for (trait_did, name, rhs) in proj {
 813                         simplify::merge_bounds(cx, &mut bounds, trait_did, &name, &rhs.clean(cx));
 814                     }
 815                 }
 816             } else {
 817                 unreachable!();
 818             }
 819
 820             cx.impl_trait_bounds.borrow_mut().insert(param, bounds);
 821         }
 822
 823         // Now that `cx.impl_trait_bounds` is populated, we can process
 824         // remaining predicates which could contain `impl Trait`.
 825         let mut where_predicates =
 826             where_predicates.into_iter().flat_map(|p| p.clean(cx)).collect::<Vec<_>>();
 827
 828         // Type parameters and have a Sized bound by default unless removed with
 829         // ?Sized. Scan through the predicates and mark any type parameter with
 830         // a Sized bound, removing the bounds as we find them.
 831         //
 832         // Note that associated types also have a sized bound by default, but we
 833         // don't actually know the set of associated types right here so that's
 834         // handled in cleaning associated types
 835         let mut sized_params = FxHashSet::default();
 836         where_predicates.retain(|pred| match *pred {
 837             WP::BoundPredicate { ty: Generic(ref g), ref bounds } => {
 838                 if bounds.iter().any(|b| b.is_sized_bound(cx)) {
 839                     sized_params.insert(g.clone());
 840                     false
 841                 } else {
 842                     true
 843                 }
 844             }
 845             _ => true,
 846         });
 847
 848         // Run through the type parameters again and insert a ?Sized
 849         // unbound for any we didn't find to be Sized.
 850         for tp in &stripped_typarams {
 851             if !sized_params.contains(&tp.name) {
 852                 where_predicates.push(WP::BoundPredicate {
 853                     ty: Type::Generic(tp.name.clone()),
 854                     bounds: vec![GenericBound::maybe_sized(cx)],
 855                 })
 856             }
 857         }
 858
 859         // It would be nice to collect all of the bounds on a type and recombine
 860         // them if possible, to avoid e.g., `where T: Foo, T: Bar, T: Sized, T: 'a`
 861         // and instead see `where T: Foo + Bar + Sized + 'a`
 862
 863         Generics {
 864             params: gens
 865                 .params
 866                 .iter()
 867                 .flat_map(|param| match param.kind {
 868                     ty::GenericParamDefKind::Lifetime => Some(param.clean(cx)),
 869                     ty::GenericParamDefKind::Type { .. } => None,
 870                     ty::GenericParamDefKind::Const { .. } => Some(param.clean(cx)),
 871                 })
 872                 .chain(simplify::ty_params(stripped_typarams).into_iter())
 873                 .collect(),
 874             where_predicates: simplify::where_clauses(cx, where_predicates),
 875         }
 876     }
 877 }
 878
 879 impl<'a> Clean<Method>
 880     for (&'a hir::FnSig<'a>, &'a hir::Generics<'a>, hir::BodyId, Option<hir::Defaultness>)
 881 {
 882     fn clean(&self, cx: &DocContext<'_>) -> Method {
 883         let (generics, decl) =
 884             enter_impl_trait(cx, || (self.1.clean(cx), (&*self.0.decl, self.2).clean(cx)));
 885         let (all_types, ret_types) = get_all_types(&generics, &decl, cx);
 886         Method { decl, generics, header: self.0.header, defaultness: self.3, all_types, ret_types }
 887     }
 888 }
 889
 890 impl Clean<Item> for doctree::Function<'_> {
 891     fn clean(&self, cx: &DocContext<'_>) -> Item {
 892         let (generics, decl) =
 893             enter_impl_trait(cx, || (self.generics.clean(cx), (self.decl, self.body).clean(cx)));
 894
 895         let did = cx.tcx.hir().local_def_id(self.id);
 896         let constness = if is_min_const_fn(cx.tcx, did) {
 897             hir::Constness::Const
 898         } else {
 899             hir::Constness::NotConst
 900         };
 901         let (all_types, ret_types) = get_all_types(&generics, &decl, cx);
 902         Item {
 903             name: Some(self.name.clean(cx)),
 904             attrs: self.attrs.clean(cx),
 905             source: self.whence.clean(cx),
 906             visibility: self.vis.clean(cx),
 907             stability: cx.stability(self.id).clean(cx),
 908             deprecation: cx.deprecation(self.id).clean(cx),
 909             def_id: did,
 910             inner: FunctionItem(Function {
 911                 decl,
 912                 generics,
 913                 header: hir::FnHeader { constness, ..self.header },
 914                 all_types,
 915                 ret_types,
 916             }),
 917         }
 918     }
 919 }
 920
 921 impl<'a> Clean<Arguments> for (&'a [hir::Ty<'a>], &'a [ast::Ident]) {
 922     fn clean(&self, cx: &DocContext<'_>) -> Arguments {
 923         Arguments {
 924             values: self
 925                 .0
 926                 .iter()
 927                 .enumerate()
 928                 .map(|(i, ty)| {
 929                     let mut name =
 930                         self.1.get(i).map(|ident| ident.to_string()).unwrap_or(String::new());
 931                     if name.is_empty() {
 932                         name = "_".to_string();
 933                     }
 934                     Argument { name, type_: ty.clean(cx) }
 935                 })
 936                 .collect(),
 937         }
 938     }
 939 }
 940
 941 impl<'a> Clean<Arguments> for (&'a [hir::Ty<'a>], hir::BodyId) {
 942     fn clean(&self, cx: &DocContext<'_>) -> Arguments {
 943         let body = cx.tcx.hir().body(self.1);
 944
 945         Arguments {
 946             values: self
 947                 .0
 948                 .iter()
 949                 .enumerate()
 950                 .map(|(i, ty)| Argument {
 951                     name: name_from_pat(&body.params[i].pat),
 952                     type_: ty.clean(cx),
 953                 })
 954                 .collect(),
 955         }
 956     }
 957 }
 958
 959 impl<'a, A: Copy> Clean<FnDecl> for (&'a hir::FnDecl<'a>, A)
 960 where
 961     (&'a [hir::Ty<'a>], A): Clean<Arguments>,
 962 {
 963     fn clean(&self, cx: &DocContext<'_>) -> FnDecl {
 964         FnDecl {
 965             inputs: (&self.0.inputs[..], self.1).clean(cx),
 966             output: self.0.output.clean(cx),
 967             c_variadic: self.0.c_variadic,
 968             attrs: Attributes::default(),
 969         }
 970     }
 971 }
 972
 973 impl<'tcx> Clean<FnDecl> for (DefId, ty::PolyFnSig<'tcx>) {
 974     fn clean(&self, cx: &DocContext<'_>) -> FnDecl {
 975         let (did, sig) = *self;
 976         let mut names = if cx.tcx.hir().as_local_hir_id(did).is_some() {
 977             vec![].into_iter()
 978         } else {
 979             cx.tcx.fn_arg_names(did).into_iter()
 980         };
 981
 982         FnDecl {
 983             output: Return(sig.skip_binder().output().clean(cx)),
 984             attrs: Attributes::default(),
 985             c_variadic: sig.skip_binder().c_variadic,
 986             inputs: Arguments {
 987                 values: sig
 988                     .skip_binder()
 989                     .inputs()
 990                     .iter()
 991                     .map(|t| Argument {
 992                         type_: t.clean(cx),
 993                         name: names.next().map_or(String::new(), |name| name.to_string()),
 994                     })
 995                     .collect(),
 996             },
 997         }
 998     }
 999 }
1000
1001 impl Clean<FnRetTy> for hir::FnRetTy<'_> {
1002     fn clean(&self, cx: &DocContext<'_>) -> FnRetTy {
1003         match *self {
1004             Self::Return(ref typ) => Return(typ.clean(cx)),
1005             Self::DefaultReturn(..) => DefaultReturn,
1006         }
1007     }
1008 }
1009
1010 impl Clean<Item> for doctree::Trait<'_> {
1011     fn clean(&self, cx: &DocContext<'_>) -> Item {
1012         let attrs = self.attrs.clean(cx);
1013         Item {
1014             name: Some(self.name.clean(cx)),
1015             attrs,
1016             source: self.whence.clean(cx),
1017             def_id: cx.tcx.hir().local_def_id(self.id),
1018             visibility: self.vis.clean(cx),
1019             stability: cx.stability(self.id).clean(cx),
1020             deprecation: cx.deprecation(self.id).clean(cx),
1021             inner: TraitItem(Trait {
1022                 auto: self.is_auto.clean(cx),
1023                 unsafety: self.unsafety,
1024                 items: self.items.iter().map(|ti| ti.clean(cx)).collect(),
1025                 generics: self.generics.clean(cx),
1026                 bounds: self.bounds.clean(cx),
1027                 is_auto: self.is_auto.clean(cx),
1028             }),
1029         }
1030     }
1031 }
1032
1033 impl Clean<Item> for doctree::TraitAlias<'_> {
1034     fn clean(&self, cx: &DocContext<'_>) -> Item {
1035         let attrs = self.attrs.clean(cx);
1036         Item {
1037             name: Some(self.name.clean(cx)),
1038             attrs,
1039             source: self.whence.clean(cx),
1040             def_id: cx.tcx.hir().local_def_id(self.id),
1041             visibility: self.vis.clean(cx),
1042             stability: cx.stability(self.id).clean(cx),
1043             deprecation: cx.deprecation(self.id).clean(cx),
1044             inner: TraitAliasItem(TraitAlias {
1045                 generics: self.generics.clean(cx),
1046                 bounds: self.bounds.clean(cx),
1047             }),
1048         }
1049     }
1050 }
1051
1052 impl Clean<bool> for hir::IsAuto {
1053     fn clean(&self, _: &DocContext<'_>) -> bool {
1054         match *self {
1055             hir::IsAuto::Yes => true,
1056             hir::IsAuto::No => false,
1057         }
1058     }
1059 }
1060
1061 impl Clean<Type> for hir::TraitRef<'_> {
1062     fn clean(&self, cx: &DocContext<'_>) -> Type {
1063         resolve_type(cx, self.path.clean(cx), self.hir_ref_id)
1064     }
1065 }
1066
1067 impl Clean<PolyTrait> for hir::PolyTraitRef<'_> {
1068     fn clean(&self, cx: &DocContext<'_>) -> PolyTrait {
1069         PolyTrait {
1070             trait_: self.trait_ref.clean(cx),
1071             generic_params: self.bound_generic_params.clean(cx),
1072         }
1073     }
1074 }
1075
1076 impl Clean<TypeKind> for hir::def::DefKind {
1077     fn clean(&self, _: &DocContext<'_>) -> TypeKind {
1078         match *self {
1079             hir::def::DefKind::Mod => TypeKind::Module,
1080             hir::def::DefKind::Struct => TypeKind::Struct,
1081             hir::def::DefKind::Union => TypeKind::Union,
1082             hir::def::DefKind::Enum => TypeKind::Enum,
1083             hir::def::DefKind::Trait => TypeKind::Trait,
1084             hir::def::DefKind::TyAlias => TypeKind::Typedef,
1085             hir::def::DefKind::ForeignTy => TypeKind::Foreign,
1086             hir::def::DefKind::TraitAlias => TypeKind::TraitAlias,
1087             hir::def::DefKind::Fn => TypeKind::Function,
1088             hir::def::DefKind::Const => TypeKind::Const,
1089             hir::def::DefKind::Static => TypeKind::Static,
1090             hir::def::DefKind::Macro(_) => TypeKind::Macro,
1091             _ => TypeKind::Foreign,
1092         }
1093     }
1094 }
1095
1096 impl Clean<Item> for hir::TraitItem<'_> {
1097     fn clean(&self, cx: &DocContext<'_>) -> Item {
1098         let inner = match self.kind {
1099             hir::TraitItemKind::Const(ref ty, default) => {
1100                 AssocConstItem(ty.clean(cx), default.map(|e| print_const_expr(cx, e)))
1101             }
1102             hir::TraitItemKind::Fn(ref sig, hir::TraitFn::Provided(body)) => {
1103                 MethodItem((sig, &self.generics, body, None).clean(cx))
1104             }
1105             hir::TraitItemKind::Fn(ref sig, hir::TraitFn::Required(ref names)) => {
1106                 let (generics, decl) = enter_impl_trait(cx, || {
1107                     (self.generics.clean(cx), (&*sig.decl, &names[..]).clean(cx))
1108                 });
1109                 let (all_types, ret_types) = get_all_types(&generics, &decl, cx);
1110                 TyMethodItem(TyMethod { header: sig.header, decl, generics, all_types, ret_types })
1111             }
1112             hir::TraitItemKind::Type(ref bounds, ref default) => {
1113                 AssocTypeItem(bounds.clean(cx), default.clean(cx))
1114             }
1115         };
1116         let local_did = cx.tcx.hir().local_def_id(self.hir_id);
1117         Item {
1118             name: Some(self.ident.name.clean(cx)),
1119             attrs: self.attrs.clean(cx),
1120             source: self.span.clean(cx),
1121             def_id: local_did,
1122             visibility: Visibility::Inherited,
1123             stability: get_stability(cx, local_did),
1124             deprecation: get_deprecation(cx, local_did),
1125             inner,
1126         }
1127     }
1128 }
1129
1130 impl Clean<Item> for hir::ImplItem<'_> {
1131     fn clean(&self, cx: &DocContext<'_>) -> Item {
1132         let inner = match self.kind {
1133             hir::ImplItemKind::Const(ref ty, expr) => {
1134                 AssocConstItem(ty.clean(cx), Some(print_const_expr(cx, expr)))
1135             }
1136             hir::ImplItemKind::Fn(ref sig, body) => {
1137                 MethodItem((sig, &self.generics, body, Some(self.defaultness)).clean(cx))
1138             }
1139             hir::ImplItemKind::TyAlias(ref ty) => {
1140                 let type_ = ty.clean(cx);
1141                 let item_type = type_.def_id().and_then(|did| inline::build_ty(cx, did));
1142                 TypedefItem(Typedef { type_, generics: Generics::default(), item_type }, true)
1143             }
1144             hir::ImplItemKind::OpaqueTy(ref bounds) => OpaqueTyItem(
1145                 OpaqueTy { bounds: bounds.clean(cx), generics: Generics::default() },
1146                 true,
1147             ),
1148         };
1149         let local_did = cx.tcx.hir().local_def_id(self.hir_id);
1150         Item {
1151             name: Some(self.ident.name.clean(cx)),
1152             source: self.span.clean(cx),
1153             attrs: self.attrs.clean(cx),
1154             def_id: local_did,
1155             visibility: self.vis.clean(cx),
1156             stability: get_stability(cx, local_did),
1157             deprecation: get_deprecation(cx, local_did),
1158             inner,
1159         }
1160     }
1161 }
1162
1163 impl Clean<Item> for ty::AssocItem {
1164     fn clean(&self, cx: &DocContext<'_>) -> Item {
1165         let inner = match self.kind {
1166             ty::AssocKind::Const => {
1167                 let ty = cx.tcx.type_of(self.def_id);
1168                 let default = if self.defaultness.has_value() {
1169                     Some(inline::print_inlined_const(cx, self.def_id))
1170                 } else {
1171                     None
1172                 };
1173                 AssocConstItem(ty.clean(cx), default)
1174             }
1175             ty::AssocKind::Method => {
1176                 let generics =
1177                     (cx.tcx.generics_of(self.def_id), cx.tcx.explicit_predicates_of(self.def_id))
1178                         .clean(cx);
1179                 let sig = cx.tcx.fn_sig(self.def_id);
1180                 let mut decl = (self.def_id, sig).clean(cx);
1181
1182                 if self.method_has_self_argument {
1183                     let self_ty = match self.container {
1184                         ty::ImplContainer(def_id) => cx.tcx.type_of(def_id),
1185                         ty::TraitContainer(_) => cx.tcx.types.self_param,
1186                     };
1187                     let self_arg_ty = *sig.input(0).skip_binder();
1188                     if self_arg_ty == self_ty {
1189                         decl.inputs.values[0].type_ = Generic(String::from("Self"));
1190                     } else if let ty::Ref(_, ty, _) = self_arg_ty.kind {
1191                         if ty == self_ty {
1192                             match decl.inputs.values[0].type_ {
1193                                 BorrowedRef { ref mut type_, .. } => {
1194                                     **type_ = Generic(String::from("Self"))
1195                                 }
1196                                 _ => unreachable!(),
1197                             }
1198                         }
1199                     }
1200                 }
1201
1202                 let provided = match self.container {
1203                     ty::ImplContainer(_) => true,
1204                     ty::TraitContainer(_) => self.defaultness.has_value(),
1205                 };
1206                 let (all_types, ret_types) = get_all_types(&generics, &decl, cx);
1207                 if provided {
1208                     let constness = if is_min_const_fn(cx.tcx, self.def_id) {
1209                         hir::Constness::Const
1210                     } else {
1211                         hir::Constness::NotConst
1212                     };
1213                     let asyncness = cx.tcx.asyncness(self.def_id);
1214                     let defaultness = match self.container {
1215                         ty::ImplContainer(_) => Some(self.defaultness),
1216                         ty::TraitContainer(_) => None,
1217                     };
1218                     MethodItem(Method {
1219                         generics,
1220                         decl,
1221                         header: hir::FnHeader {
1222                             unsafety: sig.unsafety(),
1223                             abi: sig.abi(),
1224                             constness,
1225                             asyncness,
1226                         },
1227                         defaultness,
1228                         all_types,
1229                         ret_types,
1230                     })
1231                 } else {
1232                     TyMethodItem(TyMethod {
1233                         generics,
1234                         decl,
1235                         header: hir::FnHeader {
1236                             unsafety: sig.unsafety(),
1237                             abi: sig.abi(),
1238                             constness: hir::Constness::NotConst,
1239                             asyncness: hir::IsAsync::NotAsync,
1240                         },
1241                         all_types,
1242                         ret_types,
1243                     })
1244                 }
1245             }
1246             ty::AssocKind::Type => {
1247                 let my_name = self.ident.name.clean(cx);
1248
1249                 if let ty::TraitContainer(did) = self.container {
1250                     // When loading a cross-crate associated type, the bounds for this type
1251                     // are actually located on the trait/impl itself, so we need to load
1252                     // all of the generics from there and then look for bounds that are
1253                     // applied to this associated type in question.
1254                     let predicates = cx.tcx.explicit_predicates_of(did);
1255                     let generics = (cx.tcx.generics_of(did), predicates).clean(cx);
1256                     let mut bounds = generics
1257                         .where_predicates
1258                         .iter()
1259                         .filter_map(|pred| {
1260                             let (name, self_type, trait_, bounds) = match *pred {
1261                                 WherePredicate::BoundPredicate {
1262                                     ty: QPath { ref name, ref self_type, ref trait_ },
1263                                     ref bounds,
1264                                 } => (name, self_type, trait_, bounds),
1265                                 _ => return None,
1266                             };
1267                             if *name != my_name {
1268                                 return None;
1269                             }
1270                             match **trait_ {
1271                                 ResolvedPath { did, .. } if did == self.container.id() => {}
1272                                 _ => return None,
1273                             }
1274                             match **self_type {
1275                                 Generic(ref s) if *s == "Self" => {}
1276                                 _ => return None,
1277                             }
1278                             Some(bounds)
1279                         })
1280                         .flat_map(|i| i.iter().cloned())
1281                         .collect::<Vec<_>>();
1282                     // Our Sized/?Sized bound didn't get handled when creating the generics
1283                     // because we didn't actually get our whole set of bounds until just now
1284                     // (some of them may have come from the trait). If we do have a sized
1285                     // bound, we remove it, and if we don't then we add the `?Sized` bound
1286                     // at the end.
1287                     match bounds.iter().position(|b| b.is_sized_bound(cx)) {
1288                         Some(i) => {
1289                             bounds.remove(i);
1290                         }
1291                         None => bounds.push(GenericBound::maybe_sized(cx)),
1292                     }
1293
1294                     let ty = if self.defaultness.has_value() {
1295                         Some(cx.tcx.type_of(self.def_id))
1296                     } else {
1297                         None
1298                     };
1299
1300                     AssocTypeItem(bounds, ty.clean(cx))
1301                 } else {
1302                     let type_ = cx.tcx.type_of(self.def_id).clean(cx);
1303                     let item_type = type_.def_id().and_then(|did| inline::build_ty(cx, did));
1304                     TypedefItem(
1305                         Typedef {
1306                             type_,
1307                             generics: Generics { params: Vec::new(), where_predicates: Vec::new() },
1308                             item_type,
1309                         },
1310                         true,
1311                     )
1312                 }
1313             }
1314             ty::AssocKind::OpaqueTy => unimplemented!(),
1315         };
1316
1317         let visibility = match self.container {
1318             ty::ImplContainer(_) => self.vis.clean(cx),
1319             ty::TraitContainer(_) => Inherited,
1320         };
1321
1322         Item {
1323             name: Some(self.ident.name.clean(cx)),
1324             visibility,
1325             stability: get_stability(cx, self.def_id),
1326             deprecation: get_deprecation(cx, self.def_id),
1327             def_id: self.def_id,
1328             attrs: inline::load_attrs(cx, self.def_id).clean(cx),
1329             source: cx.tcx.def_span(self.def_id).clean(cx),
1330             inner,
1331         }
1332     }
1333 }
1334
1335 impl Clean<Type> for hir::Ty<'_> {
1336     fn clean(&self, cx: &DocContext<'_>) -> Type {
1337         use rustc_hir::*;
1338
1339         match self.kind {
1340             TyKind::Never => Never,
1341             TyKind::Ptr(ref m) => RawPointer(m.mutbl, box m.ty.clean(cx)),
1342             TyKind::Rptr(ref l, ref m) => {
1343                 let lifetime = if l.is_elided() { None } else { Some(l.clean(cx)) };
1344                 BorrowedRef { lifetime, mutability: m.mutbl, type_: box m.ty.clean(cx) }
1345             }
1346             TyKind::Slice(ref ty) => Slice(box ty.clean(cx)),
1347             TyKind::Array(ref ty, ref length) => {
1348                 let def_id = cx.tcx.hir().local_def_id(length.hir_id);
1349                 let length = match cx.tcx.const_eval_poly(def_id) {
1350                     Ok(length) => {
1351                         print_const(cx, ty::Const::from_value(cx.tcx, length, cx.tcx.types.usize))
1352                     }
1353                     Err(_) => cx
1354                         .sess()
1355                         .source_map()
1356                         .span_to_snippet(cx.tcx.def_span(def_id))
1357                         .unwrap_or_else(|_| "_".to_string()),
1358                 };
1359                 Array(box ty.clean(cx), length)
1360             }
1361             TyKind::Tup(ref tys) => Tuple(tys.clean(cx)),
1362             TyKind::Def(item_id, _) => {
1363                 let item = cx.tcx.hir().expect_item(item_id.id);
1364                 if let hir::ItemKind::OpaqueTy(ref ty) = item.kind {
1365                     ImplTrait(ty.bounds.clean(cx))
1366                 } else {
1367                     unreachable!()
1368                 }
1369             }
1370             TyKind::Path(hir::QPath::Resolved(None, ref path)) => {
1371                 if let Res::Def(DefKind::TyParam, did) = path.res {
1372                     if let Some(new_ty) = cx.ty_substs.borrow().get(&did).cloned() {
1373                         return new_ty;
1374                     }
1375                     if let Some(bounds) = cx.impl_trait_bounds.borrow_mut().remove(&did.into()) {
1376                         return ImplTrait(bounds);
1377                     }
1378                 }
1379
1380                 let mut alias = None;
1381                 if let Res::Def(DefKind::TyAlias, def_id) = path.res {
1382                     // Substitute private type aliases
1383                     if let Some(hir_id) = cx.tcx.hir().as_local_hir_id(def_id) {
1384                         if !cx.renderinfo.borrow().access_levels.is_exported(def_id) {
1385                             alias = Some(&cx.tcx.hir().expect_item(hir_id).kind);
1386                         }
1387                     }
1388                 };
1389
1390                 if let Some(&hir::ItemKind::TyAlias(ref ty, ref generics)) = alias {
1391                     let provided_params = &path.segments.last().expect("segments were empty");
1392                     let mut ty_substs = FxHashMap::default();
1393                     let mut lt_substs = FxHashMap::default();
1394                     let mut ct_substs = FxHashMap::default();
1395                     let generic_args = provided_params.generic_args();
1396                     {
1397                         let mut indices: GenericParamCount = Default::default();
1398                         for param in generics.params.iter() {
1399                             match param.kind {
1400                                 hir::GenericParamKind::Lifetime { .. } => {
1401                                     let mut j = 0;
1402                                     let lifetime =
1403                                         generic_args.args.iter().find_map(|arg| match arg {
1404                                             hir::GenericArg::Lifetime(lt) => {
1405                                                 if indices.lifetimes == j {
1406                                                     return Some(lt);
1407                                                 }
1408                                                 j += 1;
1409                                                 None
1410                                             }
1411                                             _ => None,
1412                                         });
1413                                     if let Some(lt) = lifetime.cloned() {
1414                                         if !lt.is_elided() {
1415                                             let lt_def_id = cx.tcx.hir().local_def_id(param.hir_id);
1416                                             lt_substs.insert(lt_def_id, lt.clean(cx));
1417                                         }
1418                                     }
1419                                     indices.lifetimes += 1;
1420                                 }
1421                                 hir::GenericParamKind::Type { ref default, .. } => {
1422                                     let ty_param_def_id = cx.tcx.hir().local_def_id(param.hir_id);
1423                                     let mut j = 0;
1424                                     let type_ =
1425                                         generic_args.args.iter().find_map(|arg| match arg {
1426                                             hir::GenericArg::Type(ty) => {
1427                                                 if indices.types == j {
1428                                                     return Some(ty);
1429                                                 }
1430                                                 j += 1;
1431                                                 None
1432                                             }
1433                                             _ => None,
1434                                         });
1435                                     if let Some(ty) = type_ {
1436                                         ty_substs.insert(ty_param_def_id, ty.clean(cx));
1437                                     } else if let Some(default) = *default {
1438                                         ty_substs.insert(ty_param_def_id, default.clean(cx));
1439                                     }
1440                                     indices.types += 1;
1441                                 }
1442                                 hir::GenericParamKind::Const { .. } => {
1443                                     let const_param_def_id =
1444                                         cx.tcx.hir().local_def_id(param.hir_id);
1445                                     let mut j = 0;
1446                                     let const_ =
1447                                         generic_args.args.iter().find_map(|arg| match arg {
1448                                             hir::GenericArg::Const(ct) => {
1449                                                 if indices.consts == j {
1450                                                     return Some(ct);
1451                                                 }
1452                                                 j += 1;
1453                                                 None
1454                                             }
1455                                             _ => None,
1456                                         });
1457                                     if let Some(ct) = const_ {
1458                                         ct_substs.insert(const_param_def_id, ct.clean(cx));
1459                                     }
1460                                     // FIXME(const_generics:defaults)
1461                                     indices.consts += 1;
1462                                 }
1463                             }
1464                         }
1465                     }
1466                     return cx.enter_alias(ty_substs, lt_substs, ct_substs, || ty.clean(cx));
1467                 }
1468                 resolve_type(cx, path.clean(cx), self.hir_id)
1469             }
1470             TyKind::Path(hir::QPath::Resolved(Some(ref qself), ref p)) => {
1471                 let segments = if p.is_global() { &p.segments[1..] } else { &p.segments };
1472                 let trait_segments = &segments[..segments.len() - 1];
1473                 let trait_path = self::Path {
1474                     global: p.is_global(),
1475                     res: Res::Def(
1476                         DefKind::Trait,
1477                         cx.tcx.associated_item(p.res.def_id()).container.id(),
1478                     ),
1479                     segments: trait_segments.clean(cx),
1480                 };
1481                 Type::QPath {
1482                     name: p.segments.last().expect("segments were empty").ident.name.clean(cx),
1483                     self_type: box qself.clean(cx),
1484                     trait_: box resolve_type(cx, trait_path, self.hir_id),
1485                 }
1486             }
1487             TyKind::Path(hir::QPath::TypeRelative(ref qself, ref segment)) => {
1488                 let mut res = Res::Err;
1489                 let ty = hir_ty_to_ty(cx.tcx, self);
1490                 if let ty::Projection(proj) = ty.kind {
1491                     res = Res::Def(DefKind::Trait, proj.trait_ref(cx.tcx).def_id);
1492                 }
1493                 let trait_path = hir::Path { span: self.span, res, segments: &[] };
1494                 Type::QPath {
1495                     name: segment.ident.name.clean(cx),
1496                     self_type: box qself.clean(cx),
1497                     trait_: box resolve_type(cx, trait_path.clean(cx), self.hir_id),
1498                 }
1499             }
1500             TyKind::TraitObject(ref bounds, ref lifetime) => {
1501                 match bounds[0].clean(cx).trait_ {
1502                     ResolvedPath { path, param_names: None, did, is_generic } => {
1503                         let mut bounds: Vec<self::GenericBound> = bounds[1..]
1504                             .iter()
1505                             .map(|bound| {
1506                                 self::GenericBound::TraitBound(
1507                                     bound.clean(cx),
1508                                     hir::TraitBoundModifier::None,
1509                                 )
1510                             })
1511                             .collect();
1512                         if !lifetime.is_elided() {
1513                             bounds.push(self::GenericBound::Outlives(lifetime.clean(cx)));
1514                         }
1515                         ResolvedPath { path, param_names: Some(bounds), did, is_generic }
1516                     }
1517                     _ => Infer, // shouldn't happen
1518                 }
1519             }
1520             TyKind::BareFn(ref barefn) => BareFunction(box barefn.clean(cx)),
1521             TyKind::Infer | TyKind::Err => Infer,
1522             TyKind::Typeof(..) => panic!("unimplemented type {:?}", self.kind),
1523         }
1524     }
1525 }
1526
1527 impl<'tcx> Clean<Type> for Ty<'tcx> {
1528     fn clean(&self, cx: &DocContext<'_>) -> Type {
1529         debug!("cleaning type: {:?}", self);
1530         match self.kind {
1531             ty::Never => Never,
1532             ty::Bool => Primitive(PrimitiveType::Bool),
1533             ty::Char => Primitive(PrimitiveType::Char),
1534             ty::Int(int_ty) => Primitive(int_ty.into()),
1535             ty::Uint(uint_ty) => Primitive(uint_ty.into()),
1536             ty::Float(float_ty) => Primitive(float_ty.into()),
1537             ty::Str => Primitive(PrimitiveType::Str),
1538             ty::Slice(ty) => Slice(box ty.clean(cx)),
1539             ty::Array(ty, n) => {
1540                 let mut n = cx.tcx.lift(&n).expect("array lift failed");
1541                 n = n.eval(cx.tcx, ty::ParamEnv::reveal_all());
1542                 let n = print_const(cx, n);
1543                 Array(box ty.clean(cx), n)
1544             }
1545             ty::RawPtr(mt) => RawPointer(mt.mutbl, box mt.ty.clean(cx)),
1546             ty::Ref(r, ty, mutbl) => {
1547                 BorrowedRef { lifetime: r.clean(cx), mutability: mutbl, type_: box ty.clean(cx) }
1548             }
1549             ty::FnDef(..) | ty::FnPtr(_) => {
1550                 let ty = cx.tcx.lift(self).expect("FnPtr lift failed");
1551                 let sig = ty.fn_sig(cx.tcx);
1552                 let local_def_id = cx.tcx.hir().local_def_id_from_node_id(ast::CRATE_NODE_ID);
1553                 BareFunction(box BareFunctionDecl {
1554                     unsafety: sig.unsafety(),
1555                     generic_params: Vec::new(),
1556                     decl: (local_def_id, sig).clean(cx),
1557                     abi: sig.abi(),
1558                 })
1559             }
1560             ty::Adt(def, substs) => {
1561                 let did = def.did;
1562                 let kind = match def.adt_kind() {
1563                     AdtKind::Struct => TypeKind::Struct,
1564                     AdtKind::Union => TypeKind::Union,
1565                     AdtKind::Enum => TypeKind::Enum,
1566                 };
1567                 inline::record_extern_fqn(cx, did, kind);
1568                 let path = external_path(cx, cx.tcx.item_name(did), None, false, vec![], substs);
1569                 ResolvedPath { path, param_names: None, did, is_generic: false }
1570             }
1571             ty::Foreign(did) => {
1572                 inline::record_extern_fqn(cx, did, TypeKind::Foreign);
1573                 let path = external_path(
1574                     cx,
1575                     cx.tcx.item_name(did),
1576                     None,
1577                     false,
1578                     vec![],
1579                     InternalSubsts::empty(),
1580                 );
1581                 ResolvedPath { path, param_names: None, did, is_generic: false }
1582             }
1583             ty::Dynamic(ref obj, ref reg) => {
1584                 // HACK: pick the first `did` as the `did` of the trait object. Someone
1585                 // might want to implement "native" support for marker-trait-only
1586                 // trait objects.
1587                 let mut dids = obj.principal_def_id().into_iter().chain(obj.auto_traits());
1588                 let did = dids
1589                     .next()
1590                     .unwrap_or_else(|| panic!("found trait object `{:?}` with no traits?", self));
1591                 let substs = match obj.principal() {
1592                     Some(principal) => principal.skip_binder().substs,
1593                     // marker traits have no substs.
1594                     _ => cx.tcx.intern_substs(&[]),
1595                 };
1596
1597                 inline::record_extern_fqn(cx, did, TypeKind::Trait);
1598
1599                 let mut param_names = vec![];
1600                 reg.clean(cx).map(|b| param_names.push(GenericBound::Outlives(b)));
1601                 for did in dids {
1602                     let empty = cx.tcx.intern_substs(&[]);
1603                     let path =
1604                         external_path(cx, cx.tcx.item_name(did), Some(did), false, vec![], empty);
1605                     inline::record_extern_fqn(cx, did, TypeKind::Trait);
1606                     let bound = GenericBound::TraitBound(
1607                         PolyTrait {
1608                             trait_: ResolvedPath {
1609                                 path,
1610                                 param_names: None,
1611                                 did,
1612                                 is_generic: false,
1613                             },
1614                             generic_params: Vec::new(),
1615                         },
1616                         hir::TraitBoundModifier::None,
1617                     );
1618                     param_names.push(bound);
1619                 }
1620
1621                 let mut bindings = vec![];
1622                 for pb in obj.projection_bounds() {
1623                     bindings.push(TypeBinding {
1624                         name: cx.tcx.associated_item(pb.item_def_id()).ident.name.clean(cx),
1625                         kind: TypeBindingKind::Equality { ty: pb.skip_binder().ty.clean(cx) },
1626                     });
1627                 }
1628
1629                 let path =
1630                     external_path(cx, cx.tcx.item_name(did), Some(did), false, bindings, substs);
1631                 ResolvedPath { path, param_names: Some(param_names), did, is_generic: false }
1632             }
1633             ty::Tuple(ref t) => {
1634                 Tuple(t.iter().map(|t| t.expect_ty()).collect::<Vec<_>>().clean(cx))
1635             }
1636
1637             ty::Projection(ref data) => data.clean(cx),
1638
1639             ty::Param(ref p) => {
1640                 if let Some(bounds) = cx.impl_trait_bounds.borrow_mut().remove(&p.index.into()) {
1641                     ImplTrait(bounds)
1642                 } else {
1643                     Generic(p.name.to_string())
1644                 }
1645             }
1646
1647             ty::Opaque(def_id, substs) => {
1648                 // Grab the "TraitA + TraitB" from `impl TraitA + TraitB`,
1649                 // by looking up the projections associated with the def_id.
1650                 let predicates_of = cx.tcx.explicit_predicates_of(def_id);
1651                 let substs = cx.tcx.lift(&substs).expect("Opaque lift failed");
1652                 let bounds = predicates_of.instantiate(cx.tcx, substs);
1653                 let mut regions = vec![];
1654                 let mut has_sized = false;
1655                 let mut bounds = bounds
1656                     .predicates
1657                     .iter()
1658                     .filter_map(|predicate| {
1659                         let trait_ref = if let Some(tr) = predicate.to_opt_poly_trait_ref() {
1660                             tr
1661                         } else if let ty::Predicate::TypeOutlives(pred) = *predicate {
1662                             // these should turn up at the end
1663                             pred.skip_binder()
1664                                 .1
1665                                 .clean(cx)
1666                                 .map(|r| regions.push(GenericBound::Outlives(r)));
1667                             return None;
1668                         } else {
1669                             return None;
1670                         };
1671
1672                         if let Some(sized) = cx.tcx.lang_items().sized_trait() {
1673                             if trait_ref.def_id() == sized {
1674                                 has_sized = true;
1675                                 return None;
1676                             }
1677                         }
1678
1679                         let bounds = bounds
1680                             .predicates
1681                             .iter()
1682                             .filter_map(|pred| {
1683                                 if let ty::Predicate::Projection(proj) = *pred {
1684                                     let proj = proj.skip_binder();
1685                                     if proj.projection_ty.trait_ref(cx.tcx)
1686                                         == *trait_ref.skip_binder()
1687                                     {
1688                                         Some(TypeBinding {
1689                                             name: cx
1690                                                 .tcx
1691                                                 .associated_item(proj.projection_ty.item_def_id)
1692                                                 .ident
1693                                                 .name
1694                                                 .clean(cx),
1695                                             kind: TypeBindingKind::Equality {
1696                                                 ty: proj.ty.clean(cx),
1697                                             },
1698                                         })
1699                                     } else {
1700                                         None
1701                                     }
1702                                 } else {
1703                                     None
1704                                 }
1705                             })
1706                             .collect();
1707
1708                         Some((trait_ref.skip_binder(), bounds).clean(cx))
1709                     })
1710                     .collect::<Vec<_>>();
1711                 bounds.extend(regions);
1712                 if !has_sized && !bounds.is_empty() {
1713                     bounds.insert(0, GenericBound::maybe_sized(cx));
1714                 }
1715                 ImplTrait(bounds)
1716             }
1717
1718             ty::Closure(..) | ty::Generator(..) => Tuple(vec![]), // FIXME(pcwalton)
1719
1720             ty::Bound(..) => panic!("Bound"),
1721             ty::Placeholder(..) => panic!("Placeholder"),
1722             ty::UnnormalizedProjection(..) => panic!("UnnormalizedProjection"),
1723             ty::GeneratorWitness(..) => panic!("GeneratorWitness"),
1724             ty::Infer(..) => panic!("Infer"),
1725             ty::Error => panic!("Error"),
1726         }
1727     }
1728 }
1729
1730 impl<'tcx> Clean<Constant> for ty::Const<'tcx> {
1731     fn clean(&self, cx: &DocContext<'_>) -> Constant {
1732         Constant {
1733             type_: self.ty.clean(cx),
1734             expr: format!("{}", self),
1735             value: None,
1736             is_literal: false,
1737         }
1738     }
1739 }
1740
1741 impl Clean<Item> for hir::StructField<'_> {
1742     fn clean(&self, cx: &DocContext<'_>) -> Item {
1743         let local_did = cx.tcx.hir().local_def_id(self.hir_id);
1744
1745         Item {
1746             name: Some(self.ident.name).clean(cx),
1747             attrs: self.attrs.clean(cx),
1748             source: self.span.clean(cx),
1749             visibility: self.vis.clean(cx),
1750             stability: get_stability(cx, local_did),
1751             deprecation: get_deprecation(cx, local_did),
1752             def_id: local_did,
1753             inner: StructFieldItem(self.ty.clean(cx)),
1754         }
1755     }
1756 }
1757
1758 impl Clean<Item> for ty::FieldDef {
1759     fn clean(&self, cx: &DocContext<'_>) -> Item {
1760         Item {
1761             name: Some(self.ident.name).clean(cx),
1762             attrs: cx.tcx.get_attrs(self.did).clean(cx),
1763             source: cx.tcx.def_span(self.did).clean(cx),
1764             visibility: self.vis.clean(cx),
1765             stability: get_stability(cx, self.did),
1766             deprecation: get_deprecation(cx, self.did),
1767             def_id: self.did,
1768             inner: StructFieldItem(cx.tcx.type_of(self.did).clean(cx)),
1769         }
1770     }
1771 }
1772
1773 impl Clean<Visibility> for hir::Visibility<'_> {
1774     fn clean(&self, cx: &DocContext<'_>) -> Visibility {
1775         match self.node {
1776             hir::VisibilityKind::Public => Visibility::Public,
1777             hir::VisibilityKind::Inherited => Visibility::Inherited,
1778             hir::VisibilityKind::Crate(_) => Visibility::Crate,
1779             hir::VisibilityKind::Restricted { ref path, .. } => {
1780                 let path = path.clean(cx);
1781                 let did = register_res(cx, path.res);
1782                 Visibility::Restricted(did, path)
1783             }
1784         }
1785     }
1786 }
1787
1788 impl Clean<Visibility> for ty::Visibility {
1789     fn clean(&self, _: &DocContext<'_>) -> Visibility {
1790         if *self == ty::Visibility::Public { Public } else { Inherited }
1791     }
1792 }
1793
1794 impl Clean<Item> for doctree::Struct<'_> {
1795     fn clean(&self, cx: &DocContext<'_>) -> Item {
1796         Item {
1797             name: Some(self.name.clean(cx)),
1798             attrs: self.attrs.clean(cx),
1799             source: self.whence.clean(cx),
1800             def_id: cx.tcx.hir().local_def_id(self.id),
1801             visibility: self.vis.clean(cx),
1802             stability: cx.stability(self.id).clean(cx),
1803             deprecation: cx.deprecation(self.id).clean(cx),
1804             inner: StructItem(Struct {
1805                 struct_type: self.struct_type,
1806                 generics: self.generics.clean(cx),
1807                 fields: self.fields.clean(cx),
1808                 fields_stripped: false,
1809             }),
1810         }
1811     }
1812 }
1813
1814 impl Clean<Item> for doctree::Union<'_> {
1815     fn clean(&self, cx: &DocContext<'_>) -> Item {
1816         Item {
1817             name: Some(self.name.clean(cx)),
1818             attrs: self.attrs.clean(cx),
1819             source: self.whence.clean(cx),
1820             def_id: cx.tcx.hir().local_def_id(self.id),
1821             visibility: self.vis.clean(cx),
1822             stability: cx.stability(self.id).clean(cx),
1823             deprecation: cx.deprecation(self.id).clean(cx),
1824             inner: UnionItem(Union {
1825                 struct_type: self.struct_type,
1826                 generics: self.generics.clean(cx),
1827                 fields: self.fields.clean(cx),
1828                 fields_stripped: false,
1829             }),
1830         }
1831     }
1832 }
1833
1834 impl Clean<VariantStruct> for rustc_hir::VariantData<'_> {
1835     fn clean(&self, cx: &DocContext<'_>) -> VariantStruct {
1836         VariantStruct {
1837             struct_type: doctree::struct_type_from_def(self),
1838             fields: self.fields().iter().map(|x| x.clean(cx)).collect(),
1839             fields_stripped: false,
1840         }
1841     }
1842 }
1843
1844 impl Clean<Item> for doctree::Enum<'_> {
1845     fn clean(&self, cx: &DocContext<'_>) -> Item {
1846         Item {
1847             name: Some(self.name.clean(cx)),
1848             attrs: self.attrs.clean(cx),
1849             source: self.whence.clean(cx),
1850             def_id: cx.tcx.hir().local_def_id(self.id),
1851             visibility: self.vis.clean(cx),
1852             stability: cx.stability(self.id).clean(cx),
1853             deprecation: cx.deprecation(self.id).clean(cx),
1854             inner: EnumItem(Enum {
1855                 variants: self.variants.iter().map(|v| v.clean(cx)).collect(),
1856                 generics: self.generics.clean(cx),
1857                 variants_stripped: false,
1858             }),
1859         }
1860     }
1861 }
1862
1863 impl Clean<Item> for doctree::Variant<'_> {
1864     fn clean(&self, cx: &DocContext<'_>) -> Item {
1865         Item {
1866             name: Some(self.name.clean(cx)),
1867             attrs: self.attrs.clean(cx),
1868             source: self.whence.clean(cx),
1869             visibility: Inherited,
1870             stability: cx.stability(self.id).clean(cx),
1871             deprecation: cx.deprecation(self.id).clean(cx),
1872             def_id: cx.tcx.hir().local_def_id(self.id),
1873             inner: VariantItem(Variant { kind: self.def.clean(cx) }),
1874         }
1875     }
1876 }
1877
1878 impl Clean<Item> for ty::VariantDef {
1879     fn clean(&self, cx: &DocContext<'_>) -> Item {
1880         let kind = match self.ctor_kind {
1881             CtorKind::Const => VariantKind::CLike,
1882             CtorKind::Fn => VariantKind::Tuple(
1883                 self.fields.iter().map(|f| cx.tcx.type_of(f.did).clean(cx)).collect(),
1884             ),
1885             CtorKind::Fictive => VariantKind::Struct(VariantStruct {
1886                 struct_type: doctree::Plain,
1887                 fields_stripped: false,
1888                 fields: self
1889                     .fields
1890                     .iter()
1891                     .map(|field| Item {
1892                         source: cx.tcx.def_span(field.did).clean(cx),
1893                         name: Some(field.ident.name.clean(cx)),
1894                         attrs: cx.tcx.get_attrs(field.did).clean(cx),
1895                         visibility: field.vis.clean(cx),
1896                         def_id: field.did,
1897                         stability: get_stability(cx, field.did),
1898                         deprecation: get_deprecation(cx, field.did),
1899                         inner: StructFieldItem(cx.tcx.type_of(field.did).clean(cx)),
1900                     })
1901                     .collect(),
1902             }),
1903         };
1904         Item {
1905             name: Some(self.ident.clean(cx)),
1906             attrs: inline::load_attrs(cx, self.def_id).clean(cx),
1907             source: cx.tcx.def_span(self.def_id).clean(cx),
1908             visibility: Inherited,
1909             def_id: self.def_id,
1910             inner: VariantItem(Variant { kind }),
1911             stability: get_stability(cx, self.def_id),
1912             deprecation: get_deprecation(cx, self.def_id),
1913         }
1914     }
1915 }
1916
1917 impl Clean<VariantKind> for hir::VariantData<'_> {
1918     fn clean(&self, cx: &DocContext<'_>) -> VariantKind {
1919         match self {
1920             hir::VariantData::Struct(..) => VariantKind::Struct(self.clean(cx)),
1921             hir::VariantData::Tuple(..) => {
1922                 VariantKind::Tuple(self.fields().iter().map(|x| x.ty.clean(cx)).collect())
1923             }
1924             hir::VariantData::Unit(..) => VariantKind::CLike,
1925         }
1926     }
1927 }
1928
1929 impl Clean<Span> for rustc_span::Span {
1930     fn clean(&self, cx: &DocContext<'_>) -> Span {
1931         if self.is_dummy() {
1932             return Span::empty();
1933         }
1934
1935         let sm = cx.sess().source_map();
1936         let filename = sm.span_to_filename(*self);
1937         let lo = sm.lookup_char_pos(self.lo());
1938         let hi = sm.lookup_char_pos(self.hi());
1939         Span {
1940             filename,
1941             loline: lo.line,
1942             locol: lo.col.to_usize(),
1943             hiline: hi.line,
1944             hicol: hi.col.to_usize(),
1945             original: *self,
1946         }
1947     }
1948 }
1949
1950 impl Clean<Path> for hir::Path<'_> {
1951     fn clean(&self, cx: &DocContext<'_>) -> Path {
1952         Path {
1953             global: self.is_global(),
1954             res: self.res,
1955             segments: if self.is_global() { &self.segments[1..] } else { &self.segments }.clean(cx),
1956         }
1957     }
1958 }
1959
1960 impl Clean<GenericArgs> for hir::GenericArgs<'_> {
1961     fn clean(&self, cx: &DocContext<'_>) -> GenericArgs {
1962         if self.parenthesized {
1963             let output = self.bindings[0].ty().clean(cx);
1964             GenericArgs::Parenthesized {
1965                 inputs: self.inputs().clean(cx),
1966                 output: if output != Type::Tuple(Vec::new()) { Some(output) } else { None },
1967             }
1968         } else {
1969             let elide_lifetimes = self.args.iter().all(|arg| match arg {
1970                 hir::GenericArg::Lifetime(lt) => lt.is_elided(),
1971                 _ => true,
1972             });
1973             GenericArgs::AngleBracketed {
1974                 args: self
1975                     .args
1976                     .iter()
1977                     .filter_map(|arg| match arg {
1978                         hir::GenericArg::Lifetime(lt) if !elide_lifetimes => {
1979                             Some(GenericArg::Lifetime(lt.clean(cx)))
1980                         }
1981                         hir::GenericArg::Lifetime(_) => None,
1982                         hir::GenericArg::Type(ty) => Some(GenericArg::Type(ty.clean(cx))),
1983                         hir::GenericArg::Const(ct) => Some(GenericArg::Const(ct.clean(cx))),
1984                     })
1985                     .collect(),
1986                 bindings: self.bindings.clean(cx),
1987             }
1988         }
1989     }
1990 }
1991
1992 impl Clean<PathSegment> for hir::PathSegment<'_> {
1993     fn clean(&self, cx: &DocContext<'_>) -> PathSegment {
1994         PathSegment { name: self.ident.name.clean(cx), args: self.generic_args().clean(cx) }
1995     }
1996 }
1997
1998 impl Clean<String> for Ident {
1999     #[inline]
2000     fn clean(&self, cx: &DocContext<'_>) -> String {
2001         self.name.clean(cx)
2002     }
2003 }
2004
2005 impl Clean<String> for ast::Name {
2006     #[inline]
2007     fn clean(&self, _: &DocContext<'_>) -> String {
2008         self.to_string()
2009     }
2010 }
2011
2012 impl Clean<Item> for doctree::Typedef<'_> {
2013     fn clean(&self, cx: &DocContext<'_>) -> Item {
2014         let type_ = self.ty.clean(cx);
2015         let item_type = type_.def_id().and_then(|did| inline::build_ty(cx, did));
2016         Item {
2017             name: Some(self.name.clean(cx)),
2018             attrs: self.attrs.clean(cx),
2019             source: self.whence.clean(cx),
2020             def_id: cx.tcx.hir().local_def_id(self.id),
2021             visibility: self.vis.clean(cx),
2022             stability: cx.stability(self.id).clean(cx),
2023             deprecation: cx.deprecation(self.id).clean(cx),
2024             inner: TypedefItem(Typedef { type_, generics: self.gen.clean(cx), item_type }, false),
2025         }
2026     }
2027 }
2028
2029 impl Clean<Item> for doctree::OpaqueTy<'_> {
2030     fn clean(&self, cx: &DocContext<'_>) -> Item {
2031         Item {
2032             name: Some(self.name.clean(cx)),
2033             attrs: self.attrs.clean(cx),
2034             source: self.whence.clean(cx),
2035             def_id: cx.tcx.hir().local_def_id(self.id),
2036             visibility: self.vis.clean(cx),
2037             stability: cx.stability(self.id).clean(cx),
2038             deprecation: cx.deprecation(self.id).clean(cx),
2039             inner: OpaqueTyItem(
2040                 OpaqueTy {
2041                     bounds: self.opaque_ty.bounds.clean(cx),
2042                     generics: self.opaque_ty.generics.clean(cx),
2043                 },
2044                 false,
2045             ),
2046         }
2047     }
2048 }
2049
2050 impl Clean<BareFunctionDecl> for hir::BareFnTy<'_> {
2051     fn clean(&self, cx: &DocContext<'_>) -> BareFunctionDecl {
2052         let (generic_params, decl) = enter_impl_trait(cx, || {
2053             (self.generic_params.clean(cx), (&*self.decl, &self.param_names[..]).clean(cx))
2054         });
2055         BareFunctionDecl { unsafety: self.unsafety, abi: self.abi, decl, generic_params }
2056     }
2057 }
2058
2059 impl Clean<Item> for doctree::Static<'_> {
2060     fn clean(&self, cx: &DocContext<'_>) -> Item {
2061         debug!("cleaning static {}: {:?}", self.name.clean(cx), self);
2062         Item {
2063             name: Some(self.name.clean(cx)),
2064             attrs: self.attrs.clean(cx),
2065             source: self.whence.clean(cx),
2066             def_id: cx.tcx.hir().local_def_id(self.id),
2067             visibility: self.vis.clean(cx),
2068             stability: cx.stability(self.id).clean(cx),
2069             deprecation: cx.deprecation(self.id).clean(cx),
2070             inner: StaticItem(Static {
2071                 type_: self.type_.clean(cx),
2072                 mutability: self.mutability,
2073                 expr: print_const_expr(cx, self.expr),
2074             }),
2075         }
2076     }
2077 }
2078
2079 impl Clean<Item> for doctree::Constant<'_> {
2080     fn clean(&self, cx: &DocContext<'_>) -> Item {
2081         let def_id = cx.tcx.hir().local_def_id(self.id);
2082
2083         Item {
2084             name: Some(self.name.clean(cx)),
2085             attrs: self.attrs.clean(cx),
2086             source: self.whence.clean(cx),
2087             def_id,
2088             visibility: self.vis.clean(cx),
2089             stability: cx.stability(self.id).clean(cx),
2090             deprecation: cx.deprecation(self.id).clean(cx),
2091             inner: ConstantItem(Constant {
2092                 type_: self.type_.clean(cx),
2093                 expr: print_const_expr(cx, self.expr),
2094                 value: print_evaluated_const(cx, def_id),
2095                 is_literal: is_literal_expr(cx, self.expr.hir_id),
2096             }),
2097         }
2098     }
2099 }
2100
2101 impl Clean<ImplPolarity> for ty::ImplPolarity {
2102     fn clean(&self, _: &DocContext<'_>) -> ImplPolarity {
2103         match self {
2104             &ty::ImplPolarity::Positive |
2105             // FIXME: do we want to do something else here?
2106             &ty::ImplPolarity::Reservation => ImplPolarity::Positive,
2107             &ty::ImplPolarity::Negative => ImplPolarity::Negative,
2108         }
2109     }
2110 }
2111
2112 impl Clean<Vec<Item>> for doctree::Impl<'_> {
2113     fn clean(&self, cx: &DocContext<'_>) -> Vec<Item> {
2114         let mut ret = Vec::new();
2115         let trait_ = self.trait_.clean(cx);
2116         let items = self.items.iter().map(|ii| ii.clean(cx)).collect::<Vec<_>>();
2117         let def_id = cx.tcx.hir().local_def_id(self.id);
2118
2119         // If this impl block is an implementation of the Deref trait, then we
2120         // need to try inlining the target's inherent impl blocks as well.
2121         if trait_.def_id() == cx.tcx.lang_items().deref_trait() {
2122             build_deref_target_impls(cx, &items, &mut ret);
2123         }
2124
2125         let provided: FxHashSet<String> = trait_
2126             .def_id()
2127             .map(|did| {
2128                 cx.tcx.provided_trait_methods(did).map(|meth| meth.ident.to_string()).collect()
2129             })
2130             .unwrap_or_default();
2131
2132         let for_ = self.for_.clean(cx);
2133         let type_alias = for_.def_id().and_then(|did| match cx.tcx.def_kind(did) {
2134             Some(DefKind::TyAlias) => Some(cx.tcx.type_of(did).clean(cx)),
2135             _ => None,
2136         });
2137         let make_item = |trait_: Option<Type>, for_: Type, items: Vec<Item>| Item {
2138             name: None,
2139             attrs: self.attrs.clean(cx),
2140             source: self.whence.clean(cx),
2141             def_id,
2142             visibility: self.vis.clean(cx),
2143             stability: cx.stability(self.id).clean(cx),
2144             deprecation: cx.deprecation(self.id).clean(cx),
2145             inner: ImplItem(Impl {
2146                 unsafety: self.unsafety,
2147                 generics: self.generics.clean(cx),
2148                 provided_trait_methods: provided.clone(),
2149                 trait_,
2150                 for_,
2151                 items,
2152                 polarity: Some(cx.tcx.impl_polarity(def_id).clean(cx)),
2153                 synthetic: false,
2154                 blanket_impl: None,
2155             }),
2156         };
2157         if let Some(type_alias) = type_alias {
2158             ret.push(make_item(trait_.clone(), type_alias, items.clone()));
2159         }
2160         ret.push(make_item(trait_, for_, items));
2161         ret
2162     }
2163 }
2164
2165 impl Clean<Vec<Item>> for doctree::ExternCrate<'_> {
2166     fn clean(&self, cx: &DocContext<'_>) -> Vec<Item> {
2167         let please_inline = self.vis.node.is_pub()
2168             && self.attrs.iter().any(|a| {
2169                 a.check_name(sym::doc)
2170                     && match a.meta_item_list() {
2171                         Some(l) => attr::list_contains_name(&l, sym::inline),
2172                         None => false,
2173                     }
2174             });
2175
2176         if please_inline {
2177             let mut visited = FxHashSet::default();
2178
2179             let res = Res::Def(DefKind::Mod, DefId { krate: self.cnum, index: CRATE_DEF_INDEX });
2180
2181             if let Some(items) = inline::try_inline(
2182                 cx,
2183                 res,
2184                 self.name,
2185                 Some(rustc_middle::ty::Attributes::Borrowed(self.attrs)),
2186                 &mut visited,
2187             ) {
2188                 return items;
2189             }
2190         }
2191
2192         vec![Item {
2193             name: None,
2194             attrs: self.attrs.clean(cx),
2195             source: self.whence.clean(cx),
2196             def_id: DefId { krate: self.cnum, index: CRATE_DEF_INDEX },
2197             visibility: self.vis.clean(cx),
2198             stability: None,
2199             deprecation: None,
2200             inner: ExternCrateItem(self.name.clean(cx), self.path.clone()),
2201         }]
2202     }
2203 }
2204
2205 impl Clean<Vec<Item>> for doctree::Import<'_> {
2206     fn clean(&self, cx: &DocContext<'_>) -> Vec<Item> {
2207         // We consider inlining the documentation of `pub use` statements, but we
2208         // forcefully don't inline if this is not public or if the
2209         // #[doc(no_inline)] attribute is present.
2210         // Don't inline doc(hidden) imports so they can be stripped at a later stage.
2211         let mut denied = !self.vis.node.is_pub()
2212             || self.attrs.iter().any(|a| {
2213                 a.check_name(sym::doc)
2214                     && match a.meta_item_list() {
2215                         Some(l) => {
2216                             attr::list_contains_name(&l, sym::no_inline)
2217                                 || attr::list_contains_name(&l, sym::hidden)
2218                         }
2219                         None => false,
2220                     }
2221             });
2222         // Also check whether imports were asked to be inlined, in case we're trying to re-export a
2223         // crate in Rust 2018+
2224         let please_inline = self.attrs.lists(sym::doc).has_word(sym::inline);
2225         let path = self.path.clean(cx);
2226         let inner = if self.glob {
2227             if !denied {
2228                 let mut visited = FxHashSet::default();
2229                 if let Some(items) = inline::try_inline_glob(cx, path.res, &mut visited) {
2230                     return items;
2231                 }
2232             }
2233
2234             Import::Glob(resolve_use_source(cx, path))
2235         } else {
2236             let name = self.name;
2237             if !please_inline {
2238                 if let Res::Def(DefKind::Mod, did) = path.res {
2239                     if !did.is_local() && did.index == CRATE_DEF_INDEX {
2240                         // if we're `pub use`ing an extern crate root, don't inline it unless we
2241                         // were specifically asked for it
2242                         denied = true;
2243                     }
2244                 }
2245             }
2246             if !denied {
2247                 let mut visited = FxHashSet::default();
2248                 if let Some(items) = inline::try_inline(
2249                     cx,
2250                     path.res,
2251                     name,
2252                     Some(rustc_middle::ty::Attributes::Borrowed(self.attrs)),
2253                     &mut visited,
2254                 ) {
2255                     return items;
2256                 }
2257             }
2258             Import::Simple(name.clean(cx), resolve_use_source(cx, path))
2259         };
2260
2261         vec![Item {
2262             name: None,
2263             attrs: self.attrs.clean(cx),
2264             source: self.whence.clean(cx),
2265             def_id: cx.tcx.hir().local_def_id_from_node_id(ast::CRATE_NODE_ID),
2266             visibility: self.vis.clean(cx),
2267             stability: None,
2268             deprecation: None,
2269             inner: ImportItem(inner),
2270         }]
2271     }
2272 }
2273
2274 impl Clean<Item> for doctree::ForeignItem<'_> {
2275     fn clean(&self, cx: &DocContext<'_>) -> Item {
2276         let inner = match self.kind {
2277             hir::ForeignItemKind::Fn(ref decl, ref names, ref generics) => {
2278                 let abi = cx.tcx.hir().get_foreign_abi(self.id);
2279                 let (generics, decl) =
2280                     enter_impl_trait(cx, || (generics.clean(cx), (&**decl, &names[..]).clean(cx)));
2281                 let (all_types, ret_types) = get_all_types(&generics, &decl, cx);
2282                 ForeignFunctionItem(Function {
2283                     decl,
2284                     generics,
2285                     header: hir::FnHeader {
2286                         unsafety: hir::Unsafety::Unsafe,
2287                         abi,
2288                         constness: hir::Constness::NotConst,
2289                         asyncness: hir::IsAsync::NotAsync,
2290                     },
2291                     all_types,
2292                     ret_types,
2293                 })
2294             }
2295             hir::ForeignItemKind::Static(ref ty, mutbl) => ForeignStaticItem(Static {
2296                 type_: ty.clean(cx),
2297                 mutability: *mutbl,
2298                 expr: String::new(),
2299             }),
2300             hir::ForeignItemKind::Type => ForeignTypeItem,
2301         };
2302
2303         Item {
2304             name: Some(self.name.clean(cx)),
2305             attrs: self.attrs.clean(cx),
2306             source: self.whence.clean(cx),
2307             def_id: cx.tcx.hir().local_def_id(self.id),
2308             visibility: self.vis.clean(cx),
2309             stability: cx.stability(self.id).clean(cx),
2310             deprecation: cx.deprecation(self.id).clean(cx),
2311             inner,
2312         }
2313     }
2314 }
2315
2316 impl Clean<Item> for doctree::Macro<'_> {
2317     fn clean(&self, cx: &DocContext<'_>) -> Item {
2318         let name = self.name.clean(cx);
2319         Item {
2320             name: Some(name.clone()),
2321             attrs: self.attrs.clean(cx),
2322             source: self.whence.clean(cx),
2323             visibility: Public,
2324             stability: cx.stability(self.hid).clean(cx),
2325             deprecation: cx.deprecation(self.hid).clean(cx),
2326             def_id: self.def_id,
2327             inner: MacroItem(Macro {
2328                 source: format!(
2329                     "macro_rules! {} {{\n{}}}",
2330                     name,
2331                     self.matchers
2332                         .iter()
2333                         .map(|span| { format!("    {} => {{ ... }};\n", span.to_src(cx)) })
2334                         .collect::<String>()
2335                 ),
2336                 imported_from: self.imported_from.clean(cx),
2337             }),
2338         }
2339     }
2340 }
2341
2342 impl Clean<Item> for doctree::ProcMacro<'_> {
2343     fn clean(&self, cx: &DocContext<'_>) -> Item {
2344         Item {
2345             name: Some(self.name.clean(cx)),
2346             attrs: self.attrs.clean(cx),
2347             source: self.whence.clean(cx),
2348             visibility: Public,
2349             stability: cx.stability(self.id).clean(cx),
2350             deprecation: cx.deprecation(self.id).clean(cx),
2351             def_id: cx.tcx.hir().local_def_id(self.id),
2352             inner: ProcMacroItem(ProcMacro { kind: self.kind, helpers: self.helpers.clean(cx) }),
2353         }
2354     }
2355 }
2356
2357 impl Clean<Stability> for attr::Stability {
2358     fn clean(&self, _: &DocContext<'_>) -> Stability {
2359         Stability {
2360             level: stability::StabilityLevel::from_attr_level(&self.level),
2361             feature: Some(self.feature.to_string()).filter(|f| !f.is_empty()),
2362             since: match self.level {
2363                 attr::Stable { ref since } => since.to_string(),
2364                 _ => String::new(),
2365             },
2366             deprecation: self.rustc_depr.as_ref().map(|d| Deprecation {
2367                 note: Some(d.reason.to_string()).filter(|r| !r.is_empty()),
2368                 since: Some(d.since.to_string()).filter(|d| !d.is_empty()),
2369             }),
2370             unstable_reason: match self.level {
2371                 attr::Unstable { reason: Some(ref reason), .. } => Some(reason.to_string()),
2372                 _ => None,
2373             },
2374             issue: match self.level {
2375                 attr::Unstable { issue, .. } => issue,
2376                 _ => None,
2377             },
2378         }
2379     }
2380 }
2381
2382 impl Clean<Deprecation> for attr::Deprecation {
2383     fn clean(&self, _: &DocContext<'_>) -> Deprecation {
2384         Deprecation {
2385             since: self.since.map(|s| s.to_string()).filter(|s| !s.is_empty()),
2386             note: self.note.map(|n| n.to_string()).filter(|n| !n.is_empty()),
2387         }
2388     }
2389 }
2390
2391 impl Clean<TypeBinding> for hir::TypeBinding<'_> {
2392     fn clean(&self, cx: &DocContext<'_>) -> TypeBinding {
2393         TypeBinding { name: self.ident.name.clean(cx), kind: self.kind.clean(cx) }
2394     }
2395 }
2396
2397 impl Clean<TypeBindingKind> for hir::TypeBindingKind<'_> {
2398     fn clean(&self, cx: &DocContext<'_>) -> TypeBindingKind {
2399         match *self {
2400             hir::TypeBindingKind::Equality { ref ty } => {
2401                 TypeBindingKind::Equality { ty: ty.clean(cx) }
2402             }
2403             hir::TypeBindingKind::Constraint { ref bounds } => {
2404                 TypeBindingKind::Constraint { bounds: bounds.iter().map(|b| b.clean(cx)).collect() }
2405             }
2406         }
2407     }
2408 }
2409
2410 enum SimpleBound {
2411     TraitBound(Vec<PathSegment>, Vec<SimpleBound>, Vec<GenericParamDef>, hir::TraitBoundModifier),
2412     Outlives(Lifetime),
2413 }
2414
2415 impl From<GenericBound> for SimpleBound {
2416     fn from(bound: GenericBound) -> Self {
2417         match bound.clone() {
2418             GenericBound::Outlives(l) => SimpleBound::Outlives(l),
2419             GenericBound::TraitBound(t, mod_) => match t.trait_ {
2420                 Type::ResolvedPath { path, param_names, .. } => SimpleBound::TraitBound(
2421                     path.segments,
2422                     param_names.map_or_else(Vec::new, |v| {
2423                         v.iter().map(|p| SimpleBound::from(p.clone())).collect()
2424                     }),
2425                     t.generic_params,
2426                     mod_,
2427                 ),
2428                 _ => panic!("Unexpected bound {:?}", bound),
2429             },
2430         }
2431     }
2432 }