src/librustdoc/html/render/print_item.rs

   1 use clean::AttributesExt;
   2
   3 use std::cmp::Ordering;
   4 use std::fmt;
   5
   6 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
   7 use rustc_hir as hir;
   8 use rustc_hir::def::CtorKind;
   9 use rustc_hir::def_id::DefId;
  10 use rustc_middle::middle::stability;
  11 use rustc_middle::span_bug;
  12 use rustc_middle::ty::layout::LayoutError;
  13 use rustc_middle::ty::{Adt, TyCtxt};
  14 use rustc_span::hygiene::MacroKind;
  15 use rustc_span::symbol::{kw, sym, Symbol};
  16 use rustc_target::abi::{Layout, Primitive, TagEncoding, Variants};
  17
  18 use super::{
  19     collect_paths_for_type, document, ensure_trailing_slash, item_ty_to_section,
  20     notable_traits_decl, render_assoc_item, render_assoc_items, render_attributes_in_code,
  21     render_attributes_in_pre, render_impl, render_stability_since_raw, write_srclink,
  22     AssocItemLink, Context, ImplRenderingParameters,
  23 };
  24 use crate::clean;
  25 use crate::formats::item_type::ItemType;
  26 use crate::formats::{AssocItemRender, Impl, RenderMode};
  27 use crate::html::escape::Escape;
  28 use crate::html::format::{
  29     join_with_double_colon, print_abi_with_space, print_constness_with_space, print_where_clause,
  30     Buffer, PrintWithSpace,
  31 };
  32 use crate::html::highlight;
  33 use crate::html::layout::Page;
  34 use crate::html::markdown::{HeadingOffset, MarkdownSummaryLine};
  35 use crate::html::url_parts_builder::UrlPartsBuilder;
  36
  37 use askama::Template;
  38
  39 const ITEM_TABLE_OPEN: &str = "<div class=\"item-table\">";
  40 const ITEM_TABLE_CLOSE: &str = "</div>";
  41 const ITEM_TABLE_ROW_OPEN: &str = "<div class=\"item-row\">";
  42 const ITEM_TABLE_ROW_CLOSE: &str = "</div>";
  43
  44 // A component in a `use` path, like `string` in std::string::ToString
  45 struct PathComponent {
  46     path: String,
  47     name: Symbol,
  48 }
  49
  50 #[derive(Template)]
  51 #[template(path = "print_item.html")]
  52 struct ItemVars<'a> {
  53     page: &'a Page<'a>,
  54     static_root_path: &'a str,
  55     typ: &'a str,
  56     name: &'a str,
  57     item_type: &'a str,
  58     path_components: Vec<PathComponent>,
  59     stability_since_raw: &'a str,
  60     src_href: Option<&'a str>,
  61 }
  62
  63 pub(super) fn print_item(cx: &Context<'_>, item: &clean::Item, buf: &mut Buffer, page: &Page<'_>) {
  64     debug_assert!(!item.is_stripped());
  65     let typ = match *item.kind {
  66         clean::ModuleItem(_) => {
  67             if item.is_crate() {
  68                 "Crate "
  69             } else {
  70                 "Module "
  71             }
  72         }
  73         clean::FunctionItem(..) | clean::ForeignFunctionItem(..) => "Function ",
  74         clean::TraitItem(..) => "Trait ",
  75         clean::StructItem(..) => "Struct ",
  76         clean::UnionItem(..) => "Union ",
  77         clean::EnumItem(..) => "Enum ",
  78         clean::TypedefItem(..) => "Type Definition ",
  79         clean::MacroItem(..) => "Macro ",
  80         clean::ProcMacroItem(ref mac) => match mac.kind {
  81             MacroKind::Bang => "Macro ",
  82             MacroKind::Attr => "Attribute Macro ",
  83             MacroKind::Derive => "Derive Macro ",
  84         },
  85         clean::PrimitiveItem(..) => "Primitive Type ",
  86         clean::StaticItem(..) | clean::ForeignStaticItem(..) => "Static ",
  87         clean::ConstantItem(..) => "Constant ",
  88         clean::ForeignTypeItem => "Foreign Type ",
  89         clean::KeywordItem(..) => "Keyword ",
  90         clean::OpaqueTyItem(..) => "Opaque Type ",
  91         clean::TraitAliasItem(..) => "Trait Alias ",
  92         _ => {
  93             // We don't generate pages for any other type.
  94             unreachable!();
  95         }
  96     };
  97     let mut stability_since_raw = Buffer::new();
  98     render_stability_since_raw(
  99         &mut stability_since_raw,
 100         item.stable_since(cx.tcx()),
 101         item.const_stability(cx.tcx()),
 102         None,
 103         None,
 104     );
 105     let stability_since_raw: String = stability_since_raw.into_inner();
 106
 107     // Write source tag
 108     //
 109     // When this item is part of a `crate use` in a downstream crate, the
 110     // source link in the downstream documentation will actually come back to
 111     // this page, and this link will be auto-clicked. The `id` attribute is
 112     // used to find the link to auto-click.
 113     let src_href =
 114         if cx.include_sources && !item.is_primitive() { cx.src_href(item) } else { None };
 115
 116     let path_components = if item.is_primitive() || item.is_keyword() {
 117         vec![]
 118     } else {
 119         let cur = &cx.current;
 120         let amt = if item.is_mod() { cur.len() - 1 } else { cur.len() };
 121         cur.iter()
 122             .enumerate()
 123             .take(amt)
 124             .map(|(i, component)| PathComponent {
 125                 path: "../".repeat(cur.len() - i - 1),
 126                 name: *component,
 127             })
 128             .collect()
 129     };
 130
 131     let item_vars = ItemVars {
 132         page,
 133         static_root_path: page.get_static_root_path(),
 134         typ,
 135         name: item.name.as_ref().unwrap().as_str(),
 136         item_type: &item.type_().to_string(),
 137         path_components,
 138         stability_since_raw: &stability_since_raw,
 139         src_href: src_href.as_deref(),
 140     };
 141
 142     item_vars.render_into(buf).unwrap();
 143
 144     match &*item.kind {
 145         clean::ModuleItem(ref m) => item_module(buf, cx, item, &m.items),
 146         clean::FunctionItem(ref f) | clean::ForeignFunctionItem(ref f) => {
 147             item_function(buf, cx, item, f)
 148         }
 149         clean::TraitItem(ref t) => item_trait(buf, cx, item, t),
 150         clean::StructItem(ref s) => item_struct(buf, cx, item, s),
 151         clean::UnionItem(ref s) => item_union(buf, cx, item, s),
 152         clean::EnumItem(ref e) => item_enum(buf, cx, item, e),
 153         clean::TypedefItem(ref t) => item_typedef(buf, cx, item, t),
 154         clean::MacroItem(ref m) => item_macro(buf, cx, item, m),
 155         clean::ProcMacroItem(ref m) => item_proc_macro(buf, cx, item, m),
 156         clean::PrimitiveItem(_) => item_primitive(buf, cx, item),
 157         clean::StaticItem(ref i) | clean::ForeignStaticItem(ref i) => item_static(buf, cx, item, i),
 158         clean::ConstantItem(ref c) => item_constant(buf, cx, item, c),
 159         clean::ForeignTypeItem => item_foreign_type(buf, cx, item),
 160         clean::KeywordItem(_) => item_keyword(buf, cx, item),
 161         clean::OpaqueTyItem(ref e) => item_opaque_ty(buf, cx, item, e),
 162         clean::TraitAliasItem(ref ta) => item_trait_alias(buf, cx, item, ta),
 163         _ => {
 164             // We don't generate pages for any other type.
 165             unreachable!();
 166         }
 167     }
 168 }
 169
 170 /// For large structs, enums, unions, etc, determine whether to hide their fields
 171 fn should_hide_fields(n_fields: usize) -> bool {
 172     n_fields > 12
 173 }
 174
 175 fn toggle_open(w: &mut Buffer, text: impl fmt::Display) {
 176     write!(
 177         w,
 178         "<details class=\"rustdoc-toggle type-contents-toggle\">\
 179             <summary class=\"hideme\">\
 180                 <span>Show {}</span>\
 181             </summary>",
 182         text
 183     );
 184 }
 185
 186 fn toggle_close(w: &mut Buffer) {
 187     w.write_str("</details>");
 188 }
 189
 190 fn item_module(w: &mut Buffer, cx: &Context<'_>, item: &clean::Item, items: &[clean::Item]) {
 191     document(w, cx, item, None, HeadingOffset::H2);
 192
 193     let mut indices = (0..items.len()).filter(|i| !items[*i].is_stripped()).collect::<Vec<usize>>();
 194
 195     // the order of item types in the listing
 196     fn reorder(ty: ItemType) -> u8 {
 197         match ty {
 198             ItemType::ExternCrate => 0,
 199             ItemType::Import => 1,
 200             ItemType::Primitive => 2,
 201             ItemType::Module => 3,
 202             ItemType::Macro => 4,
 203             ItemType::Struct => 5,
 204             ItemType::Enum => 6,
 205             ItemType::Constant => 7,
 206             ItemType::Static => 8,
 207             ItemType::Trait => 9,
 208             ItemType::Function => 10,
 209             ItemType::Typedef => 12,
 210             ItemType::Union => 13,
 211             _ => 14 + ty as u8,
 212         }
 213     }
 214
 215     fn cmp(
 216         i1: &clean::Item,
 217         i2: &clean::Item,
 218         idx1: usize,
 219         idx2: usize,
 220         tcx: TyCtxt<'_>,
 221     ) -> Ordering {
 222         let ty1 = i1.type_();
 223         let ty2 = i2.type_();
 224         if item_ty_to_section(ty1) != item_ty_to_section(ty2)
 225             || (ty1 != ty2 && (ty1 == ItemType::ExternCrate || ty2 == ItemType::ExternCrate))
 226         {
 227             return (reorder(ty1), idx1).cmp(&(reorder(ty2), idx2));
 228         }
 229         let s1 = i1.stability(tcx).as_ref().map(|s| s.level);
 230         let s2 = i2.stability(tcx).as_ref().map(|s| s.level);
 231         if let (Some(a), Some(b)) = (s1, s2) {
 232             match (a.is_stable(), b.is_stable()) {
 233                 (true, true) | (false, false) => {}
 234                 (false, true) => return Ordering::Less,
 235                 (true, false) => return Ordering::Greater,
 236             }
 237         }
 238         let lhs = i1.name.unwrap_or(kw::Empty);
 239         let rhs = i2.name.unwrap_or(kw::Empty);
 240         compare_names(lhs.as_str(), rhs.as_str())
 241     }
 242
 243     if cx.shared.sort_modules_alphabetically {
 244         indices.sort_by(|&i1, &i2| cmp(&items[i1], &items[i2], i1, i2, cx.tcx()));
 245     }
 246     // This call is to remove re-export duplicates in cases such as:
 247     //
 248     // ```
 249     // crate mod foo {
 250     //     crate mod bar {
 251     //         crate trait Double { fn foo(); }
 252     //     }
 253     // }
 254     //
 255     // crate use foo::bar::*;
 256     // crate use foo::*;
 257     // ```
 258     //
 259     // `Double` will appear twice in the generated docs.
 260     //
 261     // FIXME: This code is quite ugly and could be improved. Small issue: DefId
 262     // can be identical even if the elements are different (mostly in imports).
 263     // So in case this is an import, we keep everything by adding a "unique id"
 264     // (which is the position in the vector).
 265     indices.dedup_by_key(|i| {
 266         (
 267             items[*i].item_id,
 268             if items[*i].name.is_some() { Some(full_path(cx, &items[*i])) } else { None },
 269             items[*i].type_(),
 270             if items[*i].is_import() { *i } else { 0 },
 271         )
 272     });
 273
 274     debug!("{:?}", indices);
 275     let mut last_section = None;
 276
 277     for &idx in &indices {
 278         let myitem = &items[idx];
 279         if myitem.is_stripped() {
 280             continue;
 281         }
 282
 283         let my_section = item_ty_to_section(myitem.type_());
 284         if Some(my_section) != last_section {
 285             if last_section.is_some() {
 286                 w.write_str(ITEM_TABLE_CLOSE);
 287             }
 288             last_section = Some(my_section);
 289             write!(
 290                 w,
 291                 "<h2 id=\"{id}\" class=\"small-section-header\">\
 292                     <a href=\"#{id}\">{name}</a>\
 293                  </h2>\n{}",
 294                 ITEM_TABLE_OPEN,
 295                 id = cx.derive_id(my_section.id().to_owned()),
 296                 name = my_section.name(),
 297             );
 298         }
 299
 300         match *myitem.kind {
 301             clean::ExternCrateItem { ref src } => {
 302                 use crate::html::format::anchor;
 303
 304                 w.write_str(ITEM_TABLE_ROW_OPEN);
 305                 match *src {
 306                     Some(src) => write!(
 307                         w,
 308                         "<div class=\"item-left\"><code>{}extern crate {} as {};",
 309                         myitem.visibility.print_with_space(myitem.item_id, cx),
 310                         anchor(myitem.item_id.expect_def_id(), src, cx),
 311                         myitem.name.unwrap(),
 312                     ),
 313                     None => write!(
 314                         w,
 315                         "<div class=\"item-left\"><code>{}extern crate {};",
 316                         myitem.visibility.print_with_space(myitem.item_id, cx),
 317                         anchor(myitem.item_id.expect_def_id(), myitem.name.unwrap(), cx),
 318                     ),
 319                 }
 320                 w.write_str("</code></div>");
 321                 w.write_str(ITEM_TABLE_ROW_CLOSE);
 322             }
 323
 324             clean::ImportItem(ref import) => {
 325                 let (stab, stab_tags) = if let Some(import_def_id) = import.source.did {
 326                     let ast_attrs = cx.tcx().get_attrs_unchecked(import_def_id);
 327                     let import_attrs = Box::new(clean::Attributes::from_ast(ast_attrs, None));
 328
 329                     // Just need an item with the correct def_id and attrs
 330                     let import_item = clean::Item {
 331                         item_id: import_def_id.into(),
 332                         attrs: import_attrs,
 333                         cfg: ast_attrs.cfg(cx.tcx(), &cx.cache().hidden_cfg),
 334                         ..myitem.clone()
 335                     };
 336
 337                     let stab = import_item.stability_class(cx.tcx());
 338                     let stab_tags = Some(extra_info_tags(&import_item, item, cx.tcx()));
 339                     (stab, stab_tags)
 340                 } else {
 341                     (None, None)
 342                 };
 343
 344                 let add = if stab.is_some() { " " } else { "" };
 345
 346                 w.write_str(ITEM_TABLE_ROW_OPEN);
 347                 write!(
 348                     w,
 349                     "<div class=\"item-left {stab}{add}import-item\"{id}>\
 350                          <code>{vis}{imp}</code>\
 351                      </div>\
 352                      <div class=\"item-right docblock-short\">{stab_tags}</div>",
 353                     stab = stab.unwrap_or_default(),
 354                     add = add,
 355                     vis = myitem.visibility.print_with_space(myitem.item_id, cx),
 356                     imp = import.print(cx),
 357                     stab_tags = stab_tags.unwrap_or_default(),
 358                     id = match import.kind {
 359                         clean::ImportKind::Simple(s) =>
 360                             format!(" id=\"{}\"", cx.derive_id(format!("reexport.{}", s))),
 361                         clean::ImportKind::Glob => String::new(),
 362                     },
 363                 );
 364                 w.write_str(ITEM_TABLE_ROW_CLOSE);
 365             }
 366
 367             _ => {
 368                 if myitem.name.is_none() {
 369                     continue;
 370                 }
 371
 372                 let unsafety_flag = match *myitem.kind {
 373                     clean::FunctionItem(_) | clean::ForeignFunctionItem(_)
 374                         if myitem.fn_header(cx.tcx()).unwrap().unsafety
 375                             == hir::Unsafety::Unsafe =>
 376                     {
 377                         "<a title=\"unsafe function\" href=\"#\"><sup>⚠</sup></a>"
 378                     }
 379                     _ => "",
 380                 };
 381
 382                 let stab = myitem.stability_class(cx.tcx());
 383                 let add = if stab.is_some() { " " } else { "" };
 384
 385                 let visibility_emoji = match myitem.visibility {
 386                     clean::Visibility::Restricted(_) => {
 387                         "<span title=\"Restricted Visibility\">&nbsp;🔒</span> "
 388                     }
 389                     _ => "",
 390                 };
 391
 392                 let doc_value = myitem.doc_value().unwrap_or_default();
 393                 w.write_str(ITEM_TABLE_ROW_OPEN);
 394                 write!(
 395                     w,
 396                     "<div class=\"item-left {stab}{add}module-item\">\
 397                             <a class=\"{class}\" href=\"{href}\" title=\"{title}\">{name}</a>\
 398                             {visibility_emoji}\
 399                             {unsafety_flag}\
 400                             {stab_tags}\
 401                      </div>\
 402                      <div class=\"item-right docblock-short\">{docs}</div>",
 403                     name = myitem.name.unwrap(),
 404                     visibility_emoji = visibility_emoji,
 405                     stab_tags = extra_info_tags(myitem, item, cx.tcx()),
 406                     docs = MarkdownSummaryLine(&doc_value, &myitem.links(cx)).into_string(),
 407                     class = myitem.type_(),
 408                     add = add,
 409                     stab = stab.unwrap_or_default(),
 410                     unsafety_flag = unsafety_flag,
 411                     href = item_path(myitem.type_(), myitem.name.unwrap().as_str()),
 412                     title = [full_path(cx, myitem), myitem.type_().to_string()]
 413                         .iter()
 414                         .filter_map(|s| if !s.is_empty() { Some(s.as_str()) } else { None })
 415                         .collect::<Vec<_>>()
 416                         .join(" "),
 417                 );
 418                 w.write_str(ITEM_TABLE_ROW_CLOSE);
 419             }
 420         }
 421     }
 422
 423     if last_section.is_some() {
 424         w.write_str(ITEM_TABLE_CLOSE);
 425     }
 426 }
 427
 428 /// Render the stability, deprecation and portability tags that are displayed in the item's summary
 429 /// at the module level.
 430 fn extra_info_tags(item: &clean::Item, parent: &clean::Item, tcx: TyCtxt<'_>) -> String {
 431     let mut tags = String::new();
 432
 433     fn tag_html(class: &str, title: &str, contents: &str) -> String {
 434         format!(r#"<span class="stab {}" title="{}">{}</span>"#, class, Escape(title), contents)
 435     }
 436
 437     // The trailing space after each tag is to space it properly against the rest of the docs.
 438     if let Some(depr) = &item.deprecation(tcx) {
 439         let mut message = "Deprecated";
 440         if !stability::deprecation_in_effect(depr) {
 441             message = "Deprecation planned";
 442         }
 443         tags += &tag_html("deprecated", "", message);
 444     }
 445
 446     // The "rustc_private" crates are permanently unstable so it makes no sense
 447     // to render "unstable" everywhere.
 448     if item
 449         .stability(tcx)
 450         .as_ref()
 451         .map(|s| s.level.is_unstable() && s.feature != sym::rustc_private)
 452         == Some(true)
 453     {
 454         tags += &tag_html("unstable", "", "Experimental");
 455     }
 456
 457     let cfg = match (&item.cfg, parent.cfg.as_ref()) {
 458         (Some(cfg), Some(parent_cfg)) => cfg.simplify_with(parent_cfg),
 459         (cfg, _) => cfg.as_deref().cloned(),
 460     };
 461
 462     debug!("Portability {:?} - {:?} = {:?}", item.cfg, parent.cfg, cfg);
 463     if let Some(ref cfg) = cfg {
 464         tags += &tag_html("portability", &cfg.render_long_plain(), &cfg.render_short_html());
 465     }
 466
 467     tags
 468 }
 469
 470 fn item_function(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, f: &clean::Function) {
 471     let header = it.fn_header(cx.tcx()).expect("printing a function which isn't a function");
 472     let constness = print_constness_with_space(&header.constness, it.const_stability(cx.tcx()));
 473     let unsafety = header.unsafety.print_with_space();
 474     let abi = print_abi_with_space(header.abi).to_string();
 475     let asyncness = header.asyncness.print_with_space();
 476     let visibility = it.visibility.print_with_space(it.item_id, cx).to_string();
 477     let name = it.name.unwrap();
 478
 479     let generics_len = format!("{:#}", f.generics.print(cx)).len();
 480     let header_len = "fn ".len()
 481         + visibility.len()
 482         + constness.len()
 483         + asyncness.len()
 484         + unsafety.len()
 485         + abi.len()
 486         + name.as_str().len()
 487         + generics_len;
 488
 489     wrap_into_docblock(w, |w| {
 490         wrap_item(w, "fn", |w| {
 491             render_attributes_in_pre(w, it, "");
 492             w.reserve(header_len);
 493             write!(
 494                 w,
 495                 "{vis}{constness}{asyncness}{unsafety}{abi}fn \
 496                  {name}{generics}{decl}{notable_traits}{where_clause}",
 497                 vis = visibility,
 498                 constness = constness,
 499                 asyncness = asyncness,
 500                 unsafety = unsafety,
 501                 abi = abi,
 502                 name = name,
 503                 generics = f.generics.print(cx),
 504                 where_clause = print_where_clause(&f.generics, cx, 0, true),
 505                 decl = f.decl.full_print(header_len, 0, header.asyncness, cx),
 506                 notable_traits = notable_traits_decl(&f.decl, cx),
 507             );
 508         });
 509     });
 510     document(w, cx, it, None, HeadingOffset::H2)
 511 }
 512
 513 fn item_trait(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Trait) {
 514     let bounds = bounds(&t.bounds, false, cx);
 515     let required_types = t.items.iter().filter(|m| m.is_ty_associated_type()).collect::<Vec<_>>();
 516     let provided_types = t.items.iter().filter(|m| m.is_associated_type()).collect::<Vec<_>>();
 517     let required_consts = t.items.iter().filter(|m| m.is_ty_associated_const()).collect::<Vec<_>>();
 518     let provided_consts = t.items.iter().filter(|m| m.is_associated_const()).collect::<Vec<_>>();
 519     let required_methods = t.items.iter().filter(|m| m.is_ty_method()).collect::<Vec<_>>();
 520     let provided_methods = t.items.iter().filter(|m| m.is_method()).collect::<Vec<_>>();
 521     let count_types = required_types.len() + provided_types.len();
 522     let count_consts = required_consts.len() + provided_consts.len();
 523     let count_methods = required_methods.len() + provided_methods.len();
 524
 525     // Output the trait definition
 526     wrap_into_docblock(w, |w| {
 527         wrap_item(w, "trait", |w| {
 528             render_attributes_in_pre(w, it, "");
 529             write!(
 530                 w,
 531                 "{}{}{}trait {}{}{}",
 532                 it.visibility.print_with_space(it.item_id, cx),
 533                 t.unsafety.print_with_space(),
 534                 if t.is_auto { "auto " } else { "" },
 535                 it.name.unwrap(),
 536                 t.generics.print(cx),
 537                 bounds
 538             );
 539
 540             if !t.generics.where_predicates.is_empty() {
 541                 write!(w, "{}", print_where_clause(&t.generics, cx, 0, true));
 542             } else {
 543                 w.write_str(" ");
 544             }
 545
 546             if t.items.is_empty() {
 547                 w.write_str("{ }");
 548             } else {
 549                 // FIXME: we should be using a derived_id for the Anchors here
 550                 w.write_str("{\n");
 551                 let mut toggle = false;
 552
 553                 // If there are too many associated types, hide _everything_
 554                 if should_hide_fields(count_types) {
 555                     toggle = true;
 556                     toggle_open(
 557                         w,
 558                         format_args!(
 559                             "{} associated items",
 560                             count_types + count_consts + count_methods
 561                         ),
 562                     );
 563                 }
 564                 for types in [&required_types, &provided_types] {
 565                     for t in types {
 566                         render_assoc_item(
 567                             w,
 568                             t,
 569                             AssocItemLink::Anchor(None),
 570                             ItemType::Trait,
 571                             cx,
 572                             RenderMode::Normal,
 573                         );
 574                         w.write_str(";\n");
 575                     }
 576                 }
 577                 // If there are too many associated constants, hide everything after them
 578                 // We also do this if the types + consts is large because otherwise we could
 579                 // render a bunch of types and _then_ a bunch of consts just because both were
 580                 // _just_ under the limit
 581                 if !toggle && should_hide_fields(count_types + count_consts) {
 582                     toggle = true;
 583                     toggle_open(
 584                         w,
 585                         format_args!(
 586                             "{} associated constant{} and {} method{}",
 587                             count_consts,
 588                             pluralize(count_consts),
 589                             count_methods,
 590                             pluralize(count_methods),
 591                         ),
 592                     );
 593                 }
 594                 if count_types != 0 && (count_consts != 0 || count_methods != 0) {
 595                     w.write_str("\n");
 596                 }
 597                 for consts in [&required_consts, &provided_consts] {
 598                     for c in consts {
 599                         render_assoc_item(
 600                             w,
 601                             c,
 602                             AssocItemLink::Anchor(None),
 603                             ItemType::Trait,
 604                             cx,
 605                             RenderMode::Normal,
 606                         );
 607                         w.write_str(";\n");
 608                     }
 609                 }
 610                 if !toggle && should_hide_fields(count_methods) {
 611                     toggle = true;
 612                     toggle_open(w, format_args!("{} methods", count_methods));
 613                 }
 614                 if count_consts != 0 && count_methods != 0 {
 615                     w.write_str("\n");
 616                 }
 617                 for (pos, m) in required_methods.iter().enumerate() {
 618                     render_assoc_item(
 619                         w,
 620                         m,
 621                         AssocItemLink::Anchor(None),
 622                         ItemType::Trait,
 623                         cx,
 624                         RenderMode::Normal,
 625                     );
 626                     w.write_str(";\n");
 627
 628                     if pos < required_methods.len() - 1 {
 629                         w.write_str("<span class=\"item-spacer\"></span>");
 630                     }
 631                 }
 632                 if !required_methods.is_empty() && !provided_methods.is_empty() {
 633                     w.write_str("\n");
 634                 }
 635                 for (pos, m) in provided_methods.iter().enumerate() {
 636                     render_assoc_item(
 637                         w,
 638                         m,
 639                         AssocItemLink::Anchor(None),
 640                         ItemType::Trait,
 641                         cx,
 642                         RenderMode::Normal,
 643                     );
 644                     match *m.kind {
 645                         clean::MethodItem(ref inner, _)
 646                             if !inner.generics.where_predicates.is_empty() =>
 647                         {
 648                             w.write_str(",\n    { ... }\n");
 649                         }
 650                         _ => {
 651                             w.write_str(" { ... }\n");
 652                         }
 653                     }
 654
 655                     if pos < provided_methods.len() - 1 {
 656                         w.write_str("<span class=\"item-spacer\"></span>");
 657                     }
 658                 }
 659                 if toggle {
 660                     toggle_close(w);
 661                 }
 662                 w.write_str("}");
 663             }
 664         });
 665     });
 666
 667     // Trait documentation
 668     document(w, cx, it, None, HeadingOffset::H2);
 669
 670     fn write_small_section_header(w: &mut Buffer, id: &str, title: &str, extra_content: &str) {
 671         write!(
 672             w,
 673             "<h2 id=\"{0}\" class=\"small-section-header\">\
 674                 {1}<a href=\"#{0}\" class=\"anchor\"></a>\
 675              </h2>{2}",
 676             id, title, extra_content
 677         )
 678     }
 679
 680     fn trait_item(w: &mut Buffer, cx: &Context<'_>, m: &clean::Item, t: &clean::Item) {
 681         let name = m.name.unwrap();
 682         info!("Documenting {} on {:?}", name, t.name);
 683         let item_type = m.type_();
 684         let id = cx.derive_id(format!("{}.{}", item_type, name));
 685         let mut content = Buffer::empty_from(w);
 686         document(&mut content, cx, m, Some(t), HeadingOffset::H5);
 687         let toggled = !content.is_empty();
 688         if toggled {
 689             write!(w, "<details class=\"rustdoc-toggle\" open><summary>");
 690         }
 691         write!(w, "<div id=\"{}\" class=\"method has-srclink\">", id);
 692         write!(w, "<div class=\"rightside\">");
 693
 694         let has_stability = render_stability_since(w, m, t, cx.tcx());
 695         if has_stability {
 696             w.write_str(" · ");
 697         }
 698         write_srclink(cx, m, w);
 699         write!(w, "</div>");
 700         write!(w, "<h4 class=\"code-header\">");
 701         render_assoc_item(
 702             w,
 703             m,
 704             AssocItemLink::Anchor(Some(&id)),
 705             ItemType::Impl,
 706             cx,
 707             RenderMode::Normal,
 708         );
 709         w.write_str("</h4>");
 710         w.write_str("</div>");
 711         if toggled {
 712             write!(w, "</summary>");
 713             w.push_buffer(content);
 714             write!(w, "</details>");
 715         }
 716     }
 717
 718     if !required_types.is_empty() {
 719         write_small_section_header(
 720             w,
 721             "required-associated-types",
 722             "Required Associated Types",
 723             "<div class=\"methods\">",
 724         );
 725         for t in required_types {
 726             trait_item(w, cx, t, it);
 727         }
 728         w.write_str("</div>");
 729     }
 730     if !provided_types.is_empty() {
 731         write_small_section_header(
 732             w,
 733             "provided-associated-types",
 734             "Provided Associated Types",
 735             "<div class=\"methods\">",
 736         );
 737         for t in provided_types {
 738             trait_item(w, cx, t, it);
 739         }
 740         w.write_str("</div>");
 741     }
 742
 743     if !required_consts.is_empty() {
 744         write_small_section_header(
 745             w,
 746             "required-associated-consts",
 747             "Required Associated Constants",
 748             "<div class=\"methods\">",
 749         );
 750         for t in required_consts {
 751             trait_item(w, cx, t, it);
 752         }
 753         w.write_str("</div>");
 754     }
 755     if !provided_consts.is_empty() {
 756         write_small_section_header(
 757             w,
 758             "provided-associated-consts",
 759             "Provided Associated Constants",
 760             "<div class=\"methods\">",
 761         );
 762         for t in provided_consts {
 763             trait_item(w, cx, t, it);
 764         }
 765         w.write_str("</div>");
 766     }
 767
 768     // Output the documentation for each function individually
 769     if !required_methods.is_empty() {
 770         write_small_section_header(
 771             w,
 772             "required-methods",
 773             "Required Methods",
 774             "<div class=\"methods\">",
 775         );
 776         for m in required_methods {
 777             trait_item(w, cx, m, it);
 778         }
 779         w.write_str("</div>");
 780     }
 781     if !provided_methods.is_empty() {
 782         write_small_section_header(
 783             w,
 784             "provided-methods",
 785             "Provided Methods",
 786             "<div class=\"methods\">",
 787         );
 788         for m in provided_methods {
 789             trait_item(w, cx, m, it);
 790         }
 791         w.write_str("</div>");
 792     }
 793
 794     // If there are methods directly on this trait object, render them here.
 795     render_assoc_items(w, cx, it, it.item_id.expect_def_id(), AssocItemRender::All);
 796
 797     let cache = cx.cache();
 798     let mut extern_crates = FxHashSet::default();
 799     if let Some(implementors) = cache.implementors.get(&it.item_id.expect_def_id()) {
 800         // The DefId is for the first Type found with that name. The bool is
 801         // if any Types with the same name but different DefId have been found.
 802         let mut implementor_dups: FxHashMap<Symbol, (DefId, bool)> = FxHashMap::default();
 803         for implementor in implementors {
 804             if let Some(did) = implementor.inner_impl().for_.without_borrowed_ref().def_id(cx.cache()) &&
 805                 !did.is_local() {
 806                 extern_crates.insert(did.krate);
 807             }
 808             match implementor.inner_impl().for_.without_borrowed_ref() {
 809                 clean::Type::Path { ref path } if !path.is_assoc_ty() => {
 810                     let did = path.def_id();
 811                     let &mut (prev_did, ref mut has_duplicates) =
 812                         implementor_dups.entry(path.last()).or_insert((did, false));
 813                     if prev_did != did {
 814                         *has_duplicates = true;
 815                     }
 816                 }
 817                 _ => {}
 818             }
 819         }
 820
 821         let (local, foreign) = implementors.iter().partition::<Vec<_>, _>(|i| {
 822             i.inner_impl().for_.def_id(cache).map_or(true, |d| cache.paths.contains_key(&d))
 823         });
 824
 825         let (mut synthetic, mut concrete): (Vec<&&Impl>, Vec<&&Impl>) =
 826             local.iter().partition(|i| i.inner_impl().kind.is_auto());
 827
 828         synthetic.sort_by(|a, b| compare_impl(a, b, cx));
 829         concrete.sort_by(|a, b| compare_impl(a, b, cx));
 830
 831         if !foreign.is_empty() {
 832             write_small_section_header(w, "foreign-impls", "Implementations on Foreign Types", "");
 833
 834             for implementor in foreign {
 835                 let provided_methods = implementor.inner_impl().provided_trait_methods(cx.tcx());
 836                 let assoc_link =
 837                     AssocItemLink::GotoSource(implementor.impl_item.item_id, &provided_methods);
 838                 render_impl(
 839                     w,
 840                     cx,
 841                     implementor,
 842                     it,
 843                     assoc_link,
 844                     RenderMode::Normal,
 845                     None,
 846                     &[],
 847                     ImplRenderingParameters {
 848                         show_def_docs: false,
 849                         is_on_foreign_type: true,
 850                         show_default_items: false,
 851                         show_non_assoc_items: true,
 852                         toggle_open_by_default: false,
 853                     },
 854                 );
 855             }
 856         }
 857
 858         write_small_section_header(
 859             w,
 860             "implementors",
 861             "Implementors",
 862             "<div class=\"item-list\" id=\"implementors-list\">",
 863         );
 864         for implementor in concrete {
 865             render_implementor(cx, implementor, it, w, &implementor_dups, &[]);
 866         }
 867         w.write_str("</div>");
 868
 869         if t.is_auto {
 870             write_small_section_header(
 871                 w,
 872                 "synthetic-implementors",
 873                 "Auto implementors",
 874                 "<div class=\"item-list\" id=\"synthetic-implementors-list\">",
 875             );
 876             for implementor in synthetic {
 877                 render_implementor(
 878                     cx,
 879                     implementor,
 880                     it,
 881                     w,
 882                     &implementor_dups,
 883                     &collect_paths_for_type(implementor.inner_impl().for_.clone(), cache),
 884                 );
 885             }
 886             w.write_str("</div>");
 887         }
 888     } else {
 889         // even without any implementations to write in, we still want the heading and list, so the
 890         // implementors javascript file pulled in below has somewhere to write the impls into
 891         write_small_section_header(
 892             w,
 893             "implementors",
 894             "Implementors",
 895             "<div class=\"item-list\" id=\"implementors-list\"></div>",
 896         );
 897
 898         if t.is_auto {
 899             write_small_section_header(
 900                 w,
 901                 "synthetic-implementors",
 902                 "Auto implementors",
 903                 "<div class=\"item-list\" id=\"synthetic-implementors-list\"></div>",
 904             );
 905         }
 906     }
 907
 908     // Include implementors in crates that depend on the current crate.
 909     //
 910     // This is complicated by the way rustdoc is invoked, which is basically
 911     // the same way rustc is invoked: it gets called, one at a time, for each
 912     // crate. When building the rustdocs for the current crate, rustdoc can
 913     // see crate metadata for its dependencies, but cannot see metadata for its
 914     // dependents.
 915     //
 916     // To make this work, we generate a "hook" at this stage, and our
 917     // dependents can "plug in" to it when they build. For simplicity's sake,
 918     // it's [JSONP]: a JavaScript file with the data we need (and can parse),
 919     // surrounded by a tiny wrapper that the Rust side ignores, but allows the
 920     // JavaScript side to include without having to worry about Same Origin
 921     // Policy. The code for *that* is in `write_shared.rs`.
 922     //
 923     // This is further complicated by `#[doc(inline)]`. We want all copies
 924     // of an inlined trait to reference the same JS file, to address complex
 925     // dependency graphs like this one (lower crates depend on higher crates):
 926     //
 927     // ```text
 928     //  --------------------------------------------
 929     //  |            crate A: trait Foo            |
 930     //  --------------------------------------------
 931     //      |                               |
 932     //  --------------------------------    |
 933     //  | crate B: impl A::Foo for Bar |    |
 934     //  --------------------------------    |
 935     //      |                               |
 936     //  ---------------------------------------------
 937     //  | crate C: #[doc(inline)] use A::Foo as Baz |
 938     //  |          impl Baz for Quux                |
 939     //  ---------------------------------------------
 940     // ```
 941     //
 942     // Basically, we want `C::Baz` and `A::Foo` to show the same set of
 943     // impls, which is easier if they both treat `/implementors/A/trait.Foo.js`
 944     // as the Single Source of Truth.
 945     //
 946     // We also want the `impl Baz for Quux` to be written to
 947     // `trait.Foo.js`. However, when we generate plain HTML for `C::Baz`,
 948     // we're going to want to generate plain HTML for `impl Baz for Quux` too,
 949     // because that'll load faster, and it's better for SEO. And we don't want
 950     // the same impl to show up twice on the same page.
 951     //
 952     // To make this work, the implementors JS file has a structure kinda
 953     // like this:
 954     //
 955     // ```js
 956     // JSONP({
 957     // "B": {"impl A::Foo for Bar"},
 958     // "C": {"impl Baz for Quux"},
 959     // });
 960     // ```
 961     //
 962     // First of all, this means we can rebuild a crate, and it'll replace its own
 963     // data if something changes. That is, `rustdoc` is idempotent. The other
 964     // advantage is that we can list the crates that get included in the HTML,
 965     // and ignore them when doing the JavaScript-based part of rendering.
 966     // So C's HTML will have something like this:
 967     //
 968     // ```html
 969     // <script type="text/javascript" src="/implementors/A/trait.Foo.js"
 970     //     data-ignore-extern-crates="A,B" async></script>
 971     // ```
 972     //
 973     // And, when the JS runs, anything in data-ignore-extern-crates is known
 974     // to already be in the HTML, and will be ignored.
 975     //
 976     // [JSONP]: https://en.wikipedia.org/wiki/JSONP
 977     let mut js_src_path: UrlPartsBuilder = std::iter::repeat("..")
 978         .take(cx.current.len())
 979         .chain(std::iter::once("implementors"))
 980         .collect();
 981     if let Some(did) = it.item_id.as_def_id() &&
 982         let get_extern = { || cache.external_paths.get(&did).map(|s| s.0.clone()) } &&
 983         let Some(fqp) = cache.exact_paths.get(&did).cloned().or_else(get_extern) {
 984         js_src_path.extend(fqp[..fqp.len() - 1].iter().copied());
 985         js_src_path.push_fmt(format_args!("{}.{}.js", it.type_(), fqp.last().unwrap()));
 986     } else {
 987         js_src_path.extend(cx.current.iter().copied());
 988         js_src_path.push_fmt(format_args!("{}.{}.js", it.type_(), it.name.unwrap()));
 989     }
 990     let extern_crates = extern_crates
 991         .into_iter()
 992         .map(|cnum| cx.shared.tcx.crate_name(cnum).to_string())
 993         .collect::<Vec<_>>()
 994         .join(",");
 995     write!(
 996         w,
 997         "<script type=\"text/javascript\" src=\"{src}\" data-ignore-extern-crates=\"{extern_crates}\" async></script>",
 998         src = js_src_path.finish(),
 999     );
1000 }
1001
1002 fn item_trait_alias(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::TraitAlias) {
1003     wrap_into_docblock(w, |w| {
1004         wrap_item(w, "trait-alias", |w| {
1005             render_attributes_in_pre(w, it, "");
1006             write!(
1007                 w,
1008                 "trait {}{}{} = {};",
1009                 it.name.unwrap(),
1010                 t.generics.print(cx),
1011                 print_where_clause(&t.generics, cx, 0, true),
1012                 bounds(&t.bounds, true, cx)
1013             );
1014         });
1015     });
1016
1017     document(w, cx, it, None, HeadingOffset::H2);
1018
1019     // Render any items associated directly to this alias, as otherwise they
1020     // won't be visible anywhere in the docs. It would be nice to also show
1021     // associated items from the aliased type (see discussion in #32077), but
1022     // we need #14072 to make sense of the generics.
1023     render_assoc_items(w, cx, it, it.item_id.expect_def_id(), AssocItemRender::All)
1024 }
1025
1026 fn item_opaque_ty(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::OpaqueTy) {
1027     wrap_into_docblock(w, |w| {
1028         wrap_item(w, "opaque", |w| {
1029             render_attributes_in_pre(w, it, "");
1030             write!(
1031                 w,
1032                 "type {}{}{where_clause} = impl {bounds};",
1033                 it.name.unwrap(),
1034                 t.generics.print(cx),
1035                 where_clause = print_where_clause(&t.generics, cx, 0, true),
1036                 bounds = bounds(&t.bounds, false, cx),
1037             );
1038         });
1039     });
1040
1041     document(w, cx, it, None, HeadingOffset::H2);
1042
1043     // Render any items associated directly to this alias, as otherwise they
1044     // won't be visible anywhere in the docs. It would be nice to also show
1045     // associated items from the aliased type (see discussion in #32077), but
1046     // we need #14072 to make sense of the generics.
1047     render_assoc_items(w, cx, it, it.item_id.expect_def_id(), AssocItemRender::All)
1048 }
1049
1050 fn item_typedef(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Typedef) {
1051     fn write_content(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Typedef) {
1052         wrap_item(w, "typedef", |w| {
1053             render_attributes_in_pre(w, it, "");
1054             write!(w, "{}", it.visibility.print_with_space(it.item_id, cx));
1055             write!(
1056                 w,
1057                 "type {}{}{where_clause} = {type_};",
1058                 it.name.unwrap(),
1059                 t.generics.print(cx),
1060                 where_clause = print_where_clause(&t.generics, cx, 0, true),
1061                 type_ = t.type_.print(cx),
1062             );
1063         });
1064     }
1065
1066     wrap_into_docblock(w, |w| write_content(w, cx, it, t));
1067
1068     document(w, cx, it, None, HeadingOffset::H2);
1069
1070     let def_id = it.item_id.expect_def_id();
1071     // Render any items associated directly to this alias, as otherwise they
1072     // won't be visible anywhere in the docs. It would be nice to also show
1073     // associated items from the aliased type (see discussion in #32077), but
1074     // we need #14072 to make sense of the generics.
1075     render_assoc_items(w, cx, it, def_id, AssocItemRender::All);
1076     document_type_layout(w, cx, def_id);
1077 }
1078
1079 fn item_union(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, s: &clean::Union) {
1080     wrap_into_docblock(w, |w| {
1081         wrap_item(w, "union", |w| {
1082             render_attributes_in_pre(w, it, "");
1083             render_union(w, it, Some(&s.generics), &s.fields, "", cx);
1084         });
1085     });
1086
1087     document(w, cx, it, None, HeadingOffset::H2);
1088
1089     let mut fields = s
1090         .fields
1091         .iter()
1092         .filter_map(|f| match *f.kind {
1093             clean::StructFieldItem(ref ty) => Some((f, ty)),
1094             _ => None,
1095         })
1096         .peekable();
1097     if fields.peek().is_some() {
1098         write!(
1099             w,
1100             "<h2 id=\"fields\" class=\"fields small-section-header\">\
1101                    Fields<a href=\"#fields\" class=\"anchor\"></a></h2>"
1102         );
1103         for (field, ty) in fields {
1104             let name = field.name.expect("union field name");
1105             let id = format!("{}.{}", ItemType::StructField, name);
1106             write!(
1107                 w,
1108                 "<span id=\"{id}\" class=\"{shortty} small-section-header\">\
1109                      <a href=\"#{id}\" class=\"anchor field\"></a>\
1110                      <code>{name}: {ty}</code>\
1111                  </span>",
1112                 id = id,
1113                 name = name,
1114                 shortty = ItemType::StructField,
1115                 ty = ty.print(cx),
1116             );
1117             if let Some(stability_class) = field.stability_class(cx.tcx()) {
1118                 write!(w, "<span class=\"stab {stab}\"></span>", stab = stability_class);
1119             }
1120             document(w, cx, field, Some(it), HeadingOffset::H3);
1121         }
1122     }
1123     let def_id = it.item_id.expect_def_id();
1124     render_assoc_items(w, cx, it, def_id, AssocItemRender::All);
1125     document_type_layout(w, cx, def_id);
1126 }
1127
1128 fn print_tuple_struct_fields(w: &mut Buffer, cx: &Context<'_>, s: &[clean::Item]) {
1129     for (i, ty) in s.iter().enumerate() {
1130         if i > 0 {
1131             w.write_str(",&nbsp;");
1132         }
1133         match *ty.kind {
1134             clean::StrippedItem(box clean::StructFieldItem(_)) => w.write_str("_"),
1135             clean::StructFieldItem(ref ty) => write!(w, "{}", ty.print(cx)),
1136             _ => unreachable!(),
1137         }
1138     }
1139 }
1140
1141 fn item_enum(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, e: &clean::Enum) {
1142     wrap_into_docblock(w, |w| {
1143         wrap_item(w, "enum", |w| {
1144             render_attributes_in_pre(w, it, "");
1145             write!(
1146                 w,
1147                 "{}enum {}{}{}",
1148                 it.visibility.print_with_space(it.item_id, cx),
1149                 it.name.unwrap(),
1150                 e.generics.print(cx),
1151                 print_where_clause(&e.generics, cx, 0, true),
1152             );
1153             if e.variants.is_empty() && !e.variants_stripped {
1154                 w.write_str(" {}");
1155             } else {
1156                 w.write_str(" {\n");
1157                 let count_variants = e.variants.len();
1158                 let toggle = should_hide_fields(count_variants);
1159                 if toggle {
1160                     toggle_open(w, format_args!("{} variants", count_variants));
1161                 }
1162                 for v in &e.variants {
1163                     w.write_str("    ");
1164                     let name = v.name.unwrap();
1165                     match *v.kind {
1166                         clean::VariantItem(ref var) => match var {
1167                             clean::Variant::CLike => write!(w, "{}", name),
1168                             clean::Variant::Tuple(ref s) => {
1169                                 write!(w, "{}(", name);
1170                                 print_tuple_struct_fields(w, cx, s);
1171                                 w.write_str(")");
1172                             }
1173                             clean::Variant::Struct(ref s) => {
1174                                 render_struct(
1175                                     w,
1176                                     v,
1177                                     None,
1178                                     s.struct_type,
1179                                     &s.fields,
1180                                     "    ",
1181                                     false,
1182                                     cx,
1183                                 );
1184                             }
1185                         },
1186                         _ => unreachable!(),
1187                     }
1188                     w.write_str(",\n");
1189                 }
1190
1191                 if e.variants_stripped {
1192                     w.write_str("    // some variants omitted\n");
1193                 }
1194                 if toggle {
1195                     toggle_close(w);
1196                 }
1197                 w.write_str("}");
1198             }
1199         });
1200     });
1201
1202     document(w, cx, it, None, HeadingOffset::H2);
1203
1204     if !e.variants.is_empty() {
1205         write!(
1206             w,
1207             "<h2 id=\"variants\" class=\"variants small-section-header\">\
1208                    Variants{}<a href=\"#variants\" class=\"anchor\"></a></h2>",
1209             document_non_exhaustive_header(it)
1210         );
1211         document_non_exhaustive(w, it);
1212         for variant in &e.variants {
1213             let id = cx.derive_id(format!("{}.{}", ItemType::Variant, variant.name.unwrap()));
1214             write!(
1215                 w,
1216                 "<h3 id=\"{id}\" class=\"variant small-section-header\">\
1217                     <a href=\"#{id}\" class=\"anchor field\"></a>\
1218                     <code>{name}",
1219                 id = id,
1220                 name = variant.name.unwrap()
1221             );
1222             if let clean::VariantItem(clean::Variant::Tuple(ref s)) = *variant.kind {
1223                 w.write_str("(");
1224                 print_tuple_struct_fields(w, cx, s);
1225                 w.write_str(")");
1226             }
1227             w.write_str("</code>");
1228             render_stability_since(w, variant, it, cx.tcx());
1229             w.write_str("</h3>");
1230
1231             use crate::clean::Variant;
1232
1233             let heading_and_fields = match &*variant.kind {
1234                 clean::VariantItem(Variant::Struct(s)) => Some(("Fields", &s.fields)),
1235                 // Documentation on tuple variant fields is rare, so to reduce noise we only emit
1236                 // the section if at least one field is documented.
1237                 clean::VariantItem(Variant::Tuple(fields))
1238                     if fields.iter().any(|f| f.doc_value().is_some()) =>
1239                 {
1240                     Some(("Tuple Fields", fields))
1241                 }
1242                 _ => None,
1243             };
1244
1245             if let Some((heading, fields)) = heading_and_fields {
1246                 let variant_id =
1247                     cx.derive_id(format!("{}.{}.fields", ItemType::Variant, variant.name.unwrap()));
1248                 write!(w, "<div class=\"sub-variant\" id=\"{id}\">", id = variant_id);
1249                 write!(w, "<h4>{heading}</h4>", heading = heading);
1250                 document_non_exhaustive(w, variant);
1251                 for field in fields {
1252                     match *field.kind {
1253                         clean::StrippedItem(box clean::StructFieldItem(_)) => {}
1254                         clean::StructFieldItem(ref ty) => {
1255                             let id = cx.derive_id(format!(
1256                                 "variant.{}.field.{}",
1257                                 variant.name.unwrap(),
1258                                 field.name.unwrap()
1259                             ));
1260                             write!(
1261                                 w,
1262                                 "<div class=\"sub-variant-field\">\
1263                                  <span id=\"{id}\" class=\"variant small-section-header\">\
1264                                     <a href=\"#{id}\" class=\"anchor field\"></a>\
1265                                     <code>{f}:&nbsp;{t}</code>\
1266                                 </span>",
1267                                 id = id,
1268                                 f = field.name.unwrap(),
1269                                 t = ty.print(cx)
1270                             );
1271                             document(w, cx, field, Some(variant), HeadingOffset::H5);
1272                             write!(w, "</div>");
1273                         }
1274                         _ => unreachable!(),
1275                     }
1276                 }
1277                 w.write_str("</div>");
1278             }
1279
1280             document(w, cx, variant, Some(it), HeadingOffset::H4);
1281         }
1282     }
1283     let def_id = it.item_id.expect_def_id();
1284     render_assoc_items(w, cx, it, def_id, AssocItemRender::All);
1285     document_type_layout(w, cx, def_id);
1286 }
1287
1288 fn item_macro(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Macro) {
1289     wrap_into_docblock(w, |w| {
1290         highlight::render_with_highlighting(
1291             &t.source,
1292             w,
1293             Some("macro"),
1294             None,
1295             None,
1296             it.span(cx.tcx()).inner().edition(),
1297             None,
1298             None,
1299             None,
1300         );
1301     });
1302     document(w, cx, it, None, HeadingOffset::H2)
1303 }
1304
1305 fn item_proc_macro(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, m: &clean::ProcMacro) {
1306     wrap_into_docblock(w, |w| {
1307         let name = it.name.expect("proc-macros always have names");
1308         match m.kind {
1309             MacroKind::Bang => {
1310                 wrap_item(w, "macro", |w| {
1311                     write!(w, "{}!() {{ /* proc-macro */ }}", name);
1312                 });
1313             }
1314             MacroKind::Attr => {
1315                 wrap_item(w, "attr", |w| {
1316                     write!(w, "#[{}]", name);
1317                 });
1318             }
1319             MacroKind::Derive => {
1320                 wrap_item(w, "derive", |w| {
1321                     write!(w, "#[derive({})]", name);
1322                     if !m.helpers.is_empty() {
1323                         w.push_str("\n{\n");
1324                         w.push_str("    // Attributes available to this derive:\n");
1325                         for attr in &m.helpers {
1326                             writeln!(w, "    #[{}]", attr);
1327                         }
1328                         w.push_str("}\n");
1329                     }
1330                 });
1331             }
1332         }
1333     });
1334     document(w, cx, it, None, HeadingOffset::H2)
1335 }
1336
1337 fn item_primitive(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item) {
1338     document(w, cx, it, None, HeadingOffset::H2);
1339     render_assoc_items(w, cx, it, it.item_id.expect_def_id(), AssocItemRender::All)
1340 }
1341
1342 fn item_constant(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, c: &clean::Constant) {
1343     wrap_into_docblock(w, |w| {
1344         wrap_item(w, "const", |w| {
1345             render_attributes_in_code(w, it);
1346
1347             write!(
1348                 w,
1349                 "{vis}const {name}: {typ}",
1350                 vis = it.visibility.print_with_space(it.item_id, cx),
1351                 name = it.name.unwrap(),
1352                 typ = c.type_.print(cx),
1353             );
1354
1355             let value = c.value(cx.tcx());
1356             let is_literal = c.is_literal(cx.tcx());
1357             let expr = c.expr(cx.tcx());
1358             if value.is_some() || is_literal {
1359                 write!(w, " = {expr};", expr = Escape(&expr));
1360             } else {
1361                 w.write_str(";");
1362             }
1363
1364             if !is_literal {
1365                 if let Some(value) = &value {
1366                     let value_lowercase = value.to_lowercase();
1367                     let expr_lowercase = expr.to_lowercase();
1368
1369                     if value_lowercase != expr_lowercase
1370                         && value_lowercase.trim_end_matches("i32") != expr_lowercase
1371                     {
1372                         write!(w, " // {value}", value = Escape(value));
1373                     }
1374                 }
1375             }
1376         });
1377     });
1378
1379     document(w, cx, it, None, HeadingOffset::H2)
1380 }
1381
1382 fn item_struct(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, s: &clean::Struct) {
1383     wrap_into_docblock(w, |w| {
1384         wrap_item(w, "struct", |w| {
1385             render_attributes_in_code(w, it);
1386             render_struct(w, it, Some(&s.generics), s.struct_type, &s.fields, "", true, cx);
1387         });
1388     });
1389
1390     document(w, cx, it, None, HeadingOffset::H2);
1391
1392     let mut fields = s
1393         .fields
1394         .iter()
1395         .filter_map(|f| match *f.kind {
1396             clean::StructFieldItem(ref ty) => Some((f, ty)),
1397             _ => None,
1398         })
1399         .peekable();
1400     if let CtorKind::Fictive | CtorKind::Fn = s.struct_type {
1401         if fields.peek().is_some() {
1402             write!(
1403                 w,
1404                 "<h2 id=\"fields\" class=\"fields small-section-header\">\
1405                      {}{}<a href=\"#fields\" class=\"anchor\"></a>\
1406                  </h2>",
1407                 if let CtorKind::Fictive = s.struct_type { "Fields" } else { "Tuple Fields" },
1408                 document_non_exhaustive_header(it)
1409             );
1410             document_non_exhaustive(w, it);
1411             for (index, (field, ty)) in fields.enumerate() {
1412                 let field_name =
1413                     field.name.map_or_else(|| index.to_string(), |sym| sym.as_str().to_string());
1414                 let id = cx.derive_id(format!("{}.{}", ItemType::StructField, field_name));
1415                 write!(
1416                     w,
1417                     "<span id=\"{id}\" class=\"{item_type} small-section-header\">\
1418                          <a href=\"#{id}\" class=\"anchor field\"></a>\
1419                          <code>{name}: {ty}</code>\
1420                      </span>",
1421                     item_type = ItemType::StructField,
1422                     id = id,
1423                     name = field_name,
1424                     ty = ty.print(cx)
1425                 );
1426                 document(w, cx, field, Some(it), HeadingOffset::H3);
1427             }
1428         }
1429     }
1430     let def_id = it.item_id.expect_def_id();
1431     render_assoc_items(w, cx, it, def_id, AssocItemRender::All);
1432     document_type_layout(w, cx, def_id);
1433 }
1434
1435 fn item_static(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, s: &clean::Static) {
1436     wrap_into_docblock(w, |w| {
1437         wrap_item(w, "static", |w| {
1438             render_attributes_in_code(w, it);
1439             write!(
1440                 w,
1441                 "{vis}static {mutability}{name}: {typ}",
1442                 vis = it.visibility.print_with_space(it.item_id, cx),
1443                 mutability = s.mutability.print_with_space(),
1444                 name = it.name.unwrap(),
1445                 typ = s.type_.print(cx)
1446             );
1447         });
1448     });
1449     document(w, cx, it, None, HeadingOffset::H2)
1450 }
1451
1452 fn item_foreign_type(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item) {
1453     wrap_into_docblock(w, |w| {
1454         wrap_item(w, "foreigntype", |w| {
1455             w.write_str("extern {\n");
1456             render_attributes_in_code(w, it);
1457             write!(
1458                 w,
1459                 "    {}type {};\n}}",
1460                 it.visibility.print_with_space(it.item_id, cx),
1461                 it.name.unwrap(),
1462             );
1463         });
1464     });
1465
1466     document(w, cx, it, None, HeadingOffset::H2);
1467
1468     render_assoc_items(w, cx, it, it.item_id.expect_def_id(), AssocItemRender::All)
1469 }
1470
1471 fn item_keyword(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item) {
1472     document(w, cx, it, None, HeadingOffset::H2)
1473 }
1474
1475 /// Compare two strings treating multi-digit numbers as single units (i.e. natural sort order).
1476 crate fn compare_names(mut lhs: &str, mut rhs: &str) -> Ordering {
1477     /// Takes a non-numeric and a numeric part from the given &str.
1478     fn take_parts<'a>(s: &mut &'a str) -> (&'a str, &'a str) {
1479         let i = s.find(|c: char| c.is_ascii_digit());
1480         let (a, b) = s.split_at(i.unwrap_or(s.len()));
1481         let i = b.find(|c: char| !c.is_ascii_digit());
1482         let (b, c) = b.split_at(i.unwrap_or(b.len()));
1483         *s = c;
1484         (a, b)
1485     }
1486
1487     while !lhs.is_empty() || !rhs.is_empty() {
1488         let (la, lb) = take_parts(&mut lhs);
1489         let (ra, rb) = take_parts(&mut rhs);
1490         // First process the non-numeric part.
1491         match la.cmp(ra) {
1492             Ordering::Equal => (),
1493             x => return x,
1494         }
1495         // Then process the numeric part, if both sides have one (and they fit in a u64).
1496         if let (Ok(ln), Ok(rn)) = (lb.parse::<u64>(), rb.parse::<u64>()) {
1497             match ln.cmp(&rn) {
1498                 Ordering::Equal => (),
1499                 x => return x,
1500             }
1501         }
1502         // Then process the numeric part again, but this time as strings.
1503         match lb.cmp(rb) {
1504             Ordering::Equal => (),
1505             x => return x,
1506         }
1507     }
1508
1509     Ordering::Equal
1510 }
1511
1512 pub(super) fn full_path(cx: &Context<'_>, item: &clean::Item) -> String {
1513     let mut s = join_with_double_colon(&cx.current);
1514     s.push_str("::");
1515     s.push_str(item.name.unwrap().as_str());
1516     s
1517 }
1518
1519 pub(super) fn item_path(ty: ItemType, name: &str) -> String {
1520     match ty {
1521         ItemType::Module => format!("{}index.html", ensure_trailing_slash(name)),
1522         _ => format!("{}.{}.html", ty, name),
1523     }
1524 }
1525
1526 fn bounds(t_bounds: &[clean::GenericBound], trait_alias: bool, cx: &Context<'_>) -> String {
1527     let mut bounds = String::new();
1528     if !t_bounds.is_empty() {
1529         if !trait_alias {
1530             bounds.push_str(": ");
1531         }
1532         for (i, p) in t_bounds.iter().enumerate() {
1533             if i > 0 {
1534                 bounds.push_str(" + ");
1535             }
1536             bounds.push_str(&p.print(cx).to_string());
1537         }
1538     }
1539     bounds
1540 }
1541
1542 fn wrap_into_docblock<F>(w: &mut Buffer, f: F)
1543 where
1544     F: FnOnce(&mut Buffer),
1545 {
1546     w.write_str("<div class=\"docblock item-decl\">");
1547     f(w);
1548     w.write_str("</div>")
1549 }
1550
1551 fn wrap_item<F>(w: &mut Buffer, item_name: &str, f: F)
1552 where
1553     F: FnOnce(&mut Buffer),
1554 {
1555     w.write_fmt(format_args!("<pre class=\"rust {}\"><code>", item_name));
1556     f(w);
1557     w.write_str("</code></pre>");
1558 }
1559
1560 fn render_stability_since(
1561     w: &mut Buffer,
1562     item: &clean::Item,
1563     containing_item: &clean::Item,
1564     tcx: TyCtxt<'_>,
1565 ) -> bool {
1566     render_stability_since_raw(
1567         w,
1568         item.stable_since(tcx),
1569         item.const_stability(tcx),
1570         containing_item.stable_since(tcx),
1571         containing_item.const_stable_since(tcx),
1572     )
1573 }
1574
1575 fn compare_impl<'a, 'b>(lhs: &'a &&Impl, rhs: &'b &&Impl, cx: &Context<'_>) -> Ordering {
1576     let lhss = format!("{}", lhs.inner_impl().print(false, cx));
1577     let rhss = format!("{}", rhs.inner_impl().print(false, cx));
1578
1579     // lhs and rhs are formatted as HTML, which may be unnecessary
1580     compare_names(&lhss, &rhss)
1581 }
1582
1583 fn render_implementor(
1584     cx: &Context<'_>,
1585     implementor: &Impl,
1586     trait_: &clean::Item,
1587     w: &mut Buffer,
1588     implementor_dups: &FxHashMap<Symbol, (DefId, bool)>,
1589     aliases: &[String],
1590 ) {
1591     // If there's already another implementor that has the same abridged name, use the
1592     // full path, for example in `std::iter::ExactSizeIterator`
1593     let use_absolute = match implementor.inner_impl().for_ {
1594         clean::Type::Path { ref path, .. }
1595         | clean::BorrowedRef { type_: box clean::Type::Path { ref path, .. }, .. }
1596             if !path.is_assoc_ty() =>
1597         {
1598             implementor_dups[&path.last()].1
1599         }
1600         _ => false,
1601     };
1602     render_impl(
1603         w,
1604         cx,
1605         implementor,
1606         trait_,
1607         AssocItemLink::Anchor(None),
1608         RenderMode::Normal,
1609         Some(use_absolute),
1610         aliases,
1611         ImplRenderingParameters {
1612             show_def_docs: false,
1613             is_on_foreign_type: false,
1614             show_default_items: false,
1615             show_non_assoc_items: false,
1616             toggle_open_by_default: false,
1617         },
1618     );
1619 }
1620
1621 fn render_union(
1622     w: &mut Buffer,
1623     it: &clean::Item,
1624     g: Option<&clean::Generics>,
1625     fields: &[clean::Item],
1626     tab: &str,
1627     cx: &Context<'_>,
1628 ) {
1629     write!(w, "{}union {}", it.visibility.print_with_space(it.item_id, cx), it.name.unwrap());
1630     if let Some(g) = g {
1631         write!(w, "{}", g.print(cx));
1632         write!(w, "{}", print_where_clause(g, cx, 0, true));
1633     }
1634
1635     write!(w, " {{\n{}", tab);
1636     let count_fields =
1637         fields.iter().filter(|f| matches!(*f.kind, clean::StructFieldItem(..))).count();
1638     let toggle = should_hide_fields(count_fields);
1639     if toggle {
1640         toggle_open(w, format_args!("{} fields", count_fields));
1641     }
1642
1643     for field in fields {
1644         if let clean::StructFieldItem(ref ty) = *field.kind {
1645             write!(
1646                 w,
1647                 "    {}{}: {},\n{}",
1648                 field.visibility.print_with_space(field.item_id, cx),
1649                 field.name.unwrap(),
1650                 ty.print(cx),
1651                 tab
1652             );
1653         }
1654     }
1655
1656     if it.has_stripped_fields().unwrap() {
1657         write!(w, "    /* private fields */\n{}", tab);
1658     }
1659     if toggle {
1660         toggle_close(w);
1661     }
1662     w.write_str("}");
1663 }
1664
1665 fn render_struct(
1666     w: &mut Buffer,
1667     it: &clean::Item,
1668     g: Option<&clean::Generics>,
1669     ty: CtorKind,
1670     fields: &[clean::Item],
1671     tab: &str,
1672     structhead: bool,
1673     cx: &Context<'_>,
1674 ) {
1675     write!(
1676         w,
1677         "{}{}{}",
1678         it.visibility.print_with_space(it.item_id, cx),
1679         if structhead { "struct " } else { "" },
1680         it.name.unwrap()
1681     );
1682     if let Some(g) = g {
1683         write!(w, "{}", g.print(cx))
1684     }
1685     match ty {
1686         CtorKind::Fictive => {
1687             if let Some(g) = g {
1688                 write!(w, "{}", print_where_clause(g, cx, 0, true),)
1689             }
1690             w.write_str(" {");
1691             let count_fields =
1692                 fields.iter().filter(|f| matches!(*f.kind, clean::StructFieldItem(..))).count();
1693             let has_visible_fields = count_fields > 0;
1694             let toggle = should_hide_fields(count_fields);
1695             if toggle {
1696                 toggle_open(w, format_args!("{} fields", count_fields));
1697             }
1698             for field in fields {
1699                 if let clean::StructFieldItem(ref ty) = *field.kind {
1700                     write!(
1701                         w,
1702                         "\n{}    {}{}: {},",
1703                         tab,
1704                         field.visibility.print_with_space(field.item_id, cx),
1705                         field.name.unwrap(),
1706                         ty.print(cx),
1707                     );
1708                 }
1709             }
1710
1711             if has_visible_fields {
1712                 if it.has_stripped_fields().unwrap() {
1713                     write!(w, "\n{}    /* private fields */", tab);
1714                 }
1715                 write!(w, "\n{}", tab);
1716             } else if it.has_stripped_fields().unwrap() {
1717                 write!(w, " /* private fields */ ");
1718             }
1719             if toggle {
1720                 toggle_close(w);
1721             }
1722             w.write_str("}");
1723         }
1724         CtorKind::Fn => {
1725             w.write_str("(");
1726             for (i, field) in fields.iter().enumerate() {
1727                 if i > 0 {
1728                     w.write_str(", ");
1729                 }
1730                 match *field.kind {
1731                     clean::StrippedItem(box clean::StructFieldItem(..)) => write!(w, "_"),
1732                     clean::StructFieldItem(ref ty) => {
1733                         write!(
1734                             w,
1735                             "{}{}",
1736                             field.visibility.print_with_space(field.item_id, cx),
1737                             ty.print(cx),
1738                         )
1739                     }
1740                     _ => unreachable!(),
1741                 }
1742             }
1743             w.write_str(")");
1744             if let Some(g) = g {
1745                 write!(w, "{}", print_where_clause(g, cx, 0, false),)
1746             }
1747             // We only want a ";" when we are displaying a tuple struct, not a variant tuple struct.
1748             if structhead {
1749                 w.write_str(";");
1750             }
1751         }
1752         CtorKind::Const => {
1753             // Needed for PhantomData.
1754             if let Some(g) = g {
1755                 write!(w, "{}", print_where_clause(g, cx, 0, false),)
1756             }
1757             w.write_str(";");
1758         }
1759     }
1760 }
1761
1762 fn document_non_exhaustive_header(item: &clean::Item) -> &str {
1763     if item.is_non_exhaustive() { " (Non-exhaustive)" } else { "" }
1764 }
1765
1766 fn document_non_exhaustive(w: &mut Buffer, item: &clean::Item) {
1767     if item.is_non_exhaustive() {
1768         write!(
1769             w,
1770             "<details class=\"rustdoc-toggle non-exhaustive\">\
1771                  <summary class=\"hideme\"><span>{}</span></summary>\
1772                  <div class=\"docblock\">",
1773             {
1774                 if item.is_struct() {
1775                     "This struct is marked as non-exhaustive"
1776                 } else if item.is_enum() {
1777                     "This enum is marked as non-exhaustive"
1778                 } else if item.is_variant() {
1779                     "This variant is marked as non-exhaustive"
1780                 } else {
1781                     "This type is marked as non-exhaustive"
1782                 }
1783             }
1784         );
1785
1786         if item.is_struct() {
1787             w.write_str(
1788                 "Non-exhaustive structs could have additional fields added in future. \
1789                  Therefore, non-exhaustive structs cannot be constructed in external crates \
1790                  using the traditional <code>Struct { .. }</code> syntax; cannot be \
1791                  matched against without a wildcard <code>..</code>; and \
1792                  struct update syntax will not work.",
1793             );
1794         } else if item.is_enum() {
1795             w.write_str(
1796                 "Non-exhaustive enums could have additional variants added in future. \
1797                  Therefore, when matching against variants of non-exhaustive enums, an \
1798                  extra wildcard arm must be added to account for any future variants.",
1799             );
1800         } else if item.is_variant() {
1801             w.write_str(
1802                 "Non-exhaustive enum variants could have additional fields added in future. \
1803                  Therefore, non-exhaustive enum variants cannot be constructed in external \
1804                  crates and cannot be matched against.",
1805             );
1806         } else {
1807             w.write_str(
1808                 "This type will require a wildcard arm in any match statements or constructors.",
1809             );
1810         }
1811
1812         w.write_str("</div></details>");
1813     }
1814 }
1815
1816 fn document_type_layout(w: &mut Buffer, cx: &Context<'_>, ty_def_id: DefId) {
1817     fn write_size_of_layout(w: &mut Buffer, layout: Layout<'_>, tag_size: u64) {
1818         if layout.abi().is_unsized() {
1819             write!(w, "(unsized)");
1820         } else {
1821             let bytes = layout.size().bytes() - tag_size;
1822             write!(w, "{size} byte{pl}", size = bytes, pl = if bytes == 1 { "" } else { "s" },);
1823         }
1824     }
1825
1826     if !cx.shared.show_type_layout {
1827         return;
1828     }
1829
1830     writeln!(w, "<h2 class=\"small-section-header\">Layout</h2>");
1831     writeln!(w, "<div class=\"docblock\">");
1832
1833     let tcx = cx.tcx();
1834     let param_env = tcx.param_env(ty_def_id);
1835     let ty = tcx.type_of(ty_def_id);
1836     match tcx.layout_of(param_env.and(ty)) {
1837         Ok(ty_layout) => {
1838             writeln!(
1839                 w,
1840                 "<div class=\"warning\"><p><strong>Note:</strong> Most layout information is \
1841                  <strong>completely unstable</strong> and may even differ between compilations. \
1842                  The only exception is types with certain <code>repr(...)</code> attributes. \
1843                  Please see the Rust Reference’s \
1844                  <a href=\"https://doc.rust-lang.org/reference/type-layout.html\">“Type Layout”</a> \
1845                  chapter for details on type layout guarantees.</p></div>"
1846             );
1847             w.write_str("<p><strong>Size:</strong> ");
1848             write_size_of_layout(w, ty_layout.layout, 0);
1849             writeln!(w, "</p>");
1850             if let Variants::Multiple { variants, tag, tag_encoding, .. } =
1851                 &ty_layout.layout.variants()
1852             {
1853                 if !variants.is_empty() {
1854                     w.write_str(
1855                         "<p><strong>Size for each variant:</strong></p>\
1856                             <ul>",
1857                     );
1858
1859                     let Adt(adt, _) = ty_layout.ty.kind() else {
1860                         span_bug!(tcx.def_span(ty_def_id), "not an adt")
1861                     };
1862
1863                     let tag_size = if let TagEncoding::Niche { .. } = tag_encoding {
1864                         0
1865                     } else if let Primitive::Int(i, _) = tag.primitive() {
1866                         i.size().bytes()
1867                     } else {
1868                         span_bug!(tcx.def_span(ty_def_id), "tag is neither niche nor int")
1869                     };
1870
1871                     for (index, layout) in variants.iter_enumerated() {
1872                         let name = adt.variant(index).name;
1873                         write!(w, "<li><code>{name}</code>: ", name = name);
1874                         write_size_of_layout(w, *layout, tag_size);
1875                         writeln!(w, "</li>");
1876                     }
1877                     w.write_str("</ul>");
1878                 }
1879             }
1880         }
1881         // This kind of layout error can occur with valid code, e.g. if you try to
1882         // get the layout of a generic type such as `Vec<T>`.
1883         Err(LayoutError::Unknown(_)) => {
1884             writeln!(
1885                 w,
1886                 "<p><strong>Note:</strong> Unable to compute type layout, \
1887                  possibly due to this type having generic parameters. \
1888                  Layout can only be computed for concrete, fully-instantiated types.</p>"
1889             );
1890         }
1891         // This kind of error probably can't happen with valid code, but we don't
1892         // want to panic and prevent the docs from building, so we just let the
1893         // user know that we couldn't compute the layout.
1894         Err(LayoutError::SizeOverflow(_)) => {
1895             writeln!(
1896                 w,
1897                 "<p><strong>Note:</strong> Encountered an error during type layout; \
1898                  the type was too big.</p>"
1899             );
1900         }
1901         Err(LayoutError::NormalizationFailure(_, _)) => {
1902             writeln!(
1903                 w,
1904                 "<p><strong>Note:</strong> Encountered an error during type layout; \
1905                 the type failed to be normalized.</p>"
1906             )
1907         }
1908     }
1909
1910     writeln!(w, "</div>");
1911 }
1912
1913 fn pluralize(count: usize) -> &'static str {
1914     if count > 1 { "s" } else { "" }
1915 }