1 use clean::AttributesExt;
3 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
5 use rustc_hir::def::CtorKind;
6 use rustc_hir::def_id::DefId;
7 use rustc_middle::middle::stability;
8 use rustc_middle::span_bug;
9 use rustc_middle::ty::layout::LayoutError;
10 use rustc_middle::ty::{self, Adt, TyCtxt};
11 use rustc_span::hygiene::MacroKind;
12 use rustc_span::symbol::{kw, sym, Symbol};
13 use rustc_target::abi::{LayoutS, Primitive, TagEncoding, VariantIdx, Variants};
14 use std::cmp::Ordering;
19 collect_paths_for_type, document, ensure_trailing_slash, get_filtered_impls_for_reference,
20 item_ty_to_section, notable_traits_button, notable_traits_json, render_all_impls,
21 render_assoc_item, render_assoc_items, render_attributes_in_code, render_attributes_in_pre,
22 render_impl, render_rightside, render_stability_since_raw,
23 render_stability_since_raw_with_extra, AssocItemLink, Context, ImplRenderingParameters,
26 use crate::config::ModuleSorting;
27 use crate::formats::item_type::ItemType;
28 use crate::formats::{AssocItemRender, Impl, RenderMode};
29 use crate::html::escape::Escape;
30 use crate::html::format::{
31 join_with_double_colon, print_abi_with_space, print_constness_with_space, print_where_clause,
32 visibility_print_with_space, Buffer, Ending, PrintWithSpace,
34 use crate::html::layout::Page;
35 use crate::html::markdown::{HeadingOffset, MarkdownSummaryLine};
36 use crate::html::url_parts_builder::UrlPartsBuilder;
37 use crate::html::{highlight, static_files};
40 use itertools::Itertools;
42 const ITEM_TABLE_OPEN: &str = "<div class=\"item-table\">";
43 const ITEM_TABLE_CLOSE: &str = "</div>";
44 const ITEM_TABLE_ROW_OPEN: &str = "<div class=\"item-row\">";
45 const ITEM_TABLE_ROW_CLOSE: &str = "</div>";
47 // A component in a `use` path, like `string` in std::string::ToString
48 struct PathComponent {
54 #[template(path = "print_item.html")]
56 static_root_path: &'a str,
57 clipboard_svg: &'static static_files::StaticFile,
61 path_components: Vec<PathComponent>,
62 stability_since_raw: &'a str,
63 src_href: Option<&'a str>,
66 /// Calls `print_where_clause` and returns `true` if a `where` clause was generated.
67 fn print_where_clause_and_check<'a, 'tcx: 'a>(
69 gens: &'a clean::Generics,
70 cx: &'a Context<'tcx>,
72 let len_before = buffer.len();
73 write!(buffer, "{}", print_where_clause(gens, cx, 0, Ending::Newline));
74 len_before != buffer.len()
77 pub(super) fn print_item(
83 debug_assert!(!item.is_stripped());
84 let typ = match *item.kind {
85 clean::ModuleItem(_) => {
92 clean::FunctionItem(..) | clean::ForeignFunctionItem(..) => "Function ",
93 clean::TraitItem(..) => "Trait ",
94 clean::StructItem(..) => "Struct ",
95 clean::UnionItem(..) => "Union ",
96 clean::EnumItem(..) => "Enum ",
97 clean::TypedefItem(..) => "Type Definition ",
98 clean::MacroItem(..) => "Macro ",
99 clean::ProcMacroItem(ref mac) => match mac.kind {
100 MacroKind::Bang => "Macro ",
101 MacroKind::Attr => "Attribute Macro ",
102 MacroKind::Derive => "Derive Macro ",
104 clean::PrimitiveItem(..) => "Primitive Type ",
105 clean::StaticItem(..) | clean::ForeignStaticItem(..) => "Static ",
106 clean::ConstantItem(..) => "Constant ",
107 clean::ForeignTypeItem => "Foreign Type ",
108 clean::KeywordItem => "Keyword ",
109 clean::OpaqueTyItem(..) => "Opaque Type ",
110 clean::TraitAliasItem(..) => "Trait Alias ",
112 // We don't generate pages for any other type.
116 let mut stability_since_raw = Buffer::new();
117 render_stability_since_raw(
118 &mut stability_since_raw,
119 item.stable_since(cx.tcx()),
120 item.const_stability(cx.tcx()),
124 let stability_since_raw: String = stability_since_raw.into_inner();
128 // When this item is part of a `crate use` in a downstream crate, the
129 // source link in the downstream documentation will actually come back to
130 // this page, and this link will be auto-clicked. The `id` attribute is
131 // used to find the link to auto-click.
133 if cx.include_sources && !item.is_primitive() { cx.src_href(item) } else { None };
135 let path_components = if item.is_primitive() || item.is_keyword() {
138 let cur = &cx.current;
139 let amt = if item.is_mod() { cur.len() - 1 } else { cur.len() };
143 .map(|(i, component)| PathComponent {
144 path: "../".repeat(cur.len() - i - 1),
150 let item_vars = ItemVars {
151 static_root_path: &page.get_static_root_path(),
152 clipboard_svg: &static_files::STATIC_FILES.clipboard_svg,
154 name: item.name.as_ref().unwrap().as_str(),
155 item_type: &item.type_().to_string(),
157 stability_since_raw: &stability_since_raw,
158 src_href: src_href.as_deref(),
161 item_vars.render_into(buf).unwrap();
164 clean::ModuleItem(ref m) => item_module(buf, cx, item, &m.items),
165 clean::FunctionItem(ref f) | clean::ForeignFunctionItem(ref f) => {
166 item_function(buf, cx, item, f)
168 clean::TraitItem(ref t) => item_trait(buf, cx, item, t),
169 clean::StructItem(ref s) => item_struct(buf, cx, item, s),
170 clean::UnionItem(ref s) => item_union(buf, cx, item, s),
171 clean::EnumItem(ref e) => item_enum(buf, cx, item, e),
172 clean::TypedefItem(ref t) => item_typedef(buf, cx, item, t),
173 clean::MacroItem(ref m) => item_macro(buf, cx, item, m),
174 clean::ProcMacroItem(ref m) => item_proc_macro(buf, cx, item, m),
175 clean::PrimitiveItem(_) => item_primitive(buf, cx, item),
176 clean::StaticItem(ref i) | clean::ForeignStaticItem(ref i) => item_static(buf, cx, item, i),
177 clean::ConstantItem(ref c) => item_constant(buf, cx, item, c),
178 clean::ForeignTypeItem => item_foreign_type(buf, cx, item),
179 clean::KeywordItem => item_keyword(buf, cx, item),
180 clean::OpaqueTyItem(ref e) => item_opaque_ty(buf, cx, item, e),
181 clean::TraitAliasItem(ref ta) => item_trait_alias(buf, cx, item, ta),
183 // We don't generate pages for any other type.
188 // Render notable-traits.js used for all methods in this module.
189 if !cx.types_with_notable_traits.is_empty() {
192 r#"<script type="text/json" id="notable-traits-data">{}</script>"#,
193 notable_traits_json(cx.types_with_notable_traits.iter(), cx)
195 cx.types_with_notable_traits.clear();
199 /// For large structs, enums, unions, etc, determine whether to hide their fields
200 fn should_hide_fields(n_fields: usize) -> bool {
204 fn toggle_open(w: &mut Buffer, text: impl fmt::Display) {
207 "<details class=\"rustdoc-toggle type-contents-toggle\">\
208 <summary class=\"hideme\">\
209 <span>Show {}</span>\
215 fn toggle_close(w: &mut Buffer) {
216 w.write_str("</details>");
219 fn item_module(w: &mut Buffer, cx: &mut Context<'_>, item: &clean::Item, items: &[clean::Item]) {
220 document(w, cx, item, None, HeadingOffset::H2);
222 let mut indices = (0..items.len()).filter(|i| !items[*i].is_stripped()).collect::<Vec<usize>>();
224 // the order of item types in the listing
225 fn reorder(ty: ItemType) -> u8 {
227 ItemType::ExternCrate => 0,
228 ItemType::Import => 1,
229 ItemType::Primitive => 2,
230 ItemType::Module => 3,
231 ItemType::Macro => 4,
232 ItemType::Struct => 5,
234 ItemType::Constant => 7,
235 ItemType::Static => 8,
236 ItemType::Trait => 9,
237 ItemType::Function => 10,
238 ItemType::Typedef => 12,
239 ItemType::Union => 13,
251 let ty1 = i1.type_();
252 let ty2 = i2.type_();
253 if item_ty_to_section(ty1) != item_ty_to_section(ty2)
254 || (ty1 != ty2 && (ty1 == ItemType::ExternCrate || ty2 == ItemType::ExternCrate))
256 return (reorder(ty1), idx1).cmp(&(reorder(ty2), idx2));
258 let s1 = i1.stability(tcx).as_ref().map(|s| s.level);
259 let s2 = i2.stability(tcx).as_ref().map(|s| s.level);
260 if let (Some(a), Some(b)) = (s1, s2) {
261 match (a.is_stable(), b.is_stable()) {
262 (true, true) | (false, false) => {}
263 (false, true) => return Ordering::Less,
264 (true, false) => return Ordering::Greater,
267 let lhs = i1.name.unwrap_or(kw::Empty);
268 let rhs = i2.name.unwrap_or(kw::Empty);
269 compare_names(lhs.as_str(), rhs.as_str())
272 match cx.shared.module_sorting {
273 ModuleSorting::Alphabetical => {
274 indices.sort_by(|&i1, &i2| cmp(&items[i1], &items[i2], i1, i2, cx.tcx()));
276 ModuleSorting::DeclarationOrder => {}
278 // This call is to remove re-export duplicates in cases such as:
281 // pub(crate) mod foo {
282 // pub(crate) mod bar {
283 // pub(crate) trait Double { fn foo(); }
287 // pub(crate) use foo::bar::*;
288 // pub(crate) use foo::*;
291 // `Double` will appear twice in the generated docs.
293 // FIXME: This code is quite ugly and could be improved. Small issue: DefId
294 // can be identical even if the elements are different (mostly in imports).
295 // So in case this is an import, we keep everything by adding a "unique id"
296 // (which is the position in the vector).
297 indices.dedup_by_key(|i| {
300 if items[*i].name.is_some() { Some(full_path(cx, &items[*i])) } else { None },
302 if items[*i].is_import() { *i } else { 0 },
306 debug!("{:?}", indices);
307 let mut last_section = None;
309 for &idx in &indices {
310 let myitem = &items[idx];
311 if myitem.is_stripped() {
315 let my_section = item_ty_to_section(myitem.type_());
316 if Some(my_section) != last_section {
317 if last_section.is_some() {
318 w.write_str(ITEM_TABLE_CLOSE);
320 last_section = Some(my_section);
323 "<h2 id=\"{id}\" class=\"small-section-header\">\
324 <a href=\"#{id}\">{name}</a>\
327 id = cx.derive_id(my_section.id().to_owned()),
328 name = my_section.name(),
334 clean::ExternCrateItem { ref src } => {
335 use crate::html::format::anchor;
337 w.write_str(ITEM_TABLE_ROW_OPEN);
341 "<div class=\"item-left\"><code>{}extern crate {} as {};",
342 visibility_print_with_space(myitem.visibility(tcx), myitem.item_id, cx),
343 anchor(myitem.item_id.expect_def_id(), src, cx),
344 myitem.name.unwrap(),
348 "<div class=\"item-left\"><code>{}extern crate {};",
349 visibility_print_with_space(myitem.visibility(tcx), myitem.item_id, cx),
350 anchor(myitem.item_id.expect_def_id(), myitem.name.unwrap(), cx),
353 w.write_str("</code></div>");
354 w.write_str(ITEM_TABLE_ROW_CLOSE);
357 clean::ImportItem(ref import) => {
358 let (stab, stab_tags) = if let Some(import_def_id) = import.source.did {
359 let ast_attrs = cx.tcx().get_attrs_unchecked(import_def_id);
360 let import_attrs = Box::new(clean::Attributes::from_ast(ast_attrs));
362 // Just need an item with the correct def_id and attrs
363 let import_item = clean::Item {
364 item_id: import_def_id.into(),
366 cfg: ast_attrs.cfg(cx.tcx(), &cx.cache().hidden_cfg),
370 let stab = import_item.stability_class(cx.tcx());
371 let stab_tags = Some(extra_info_tags(&import_item, item, cx.tcx()));
377 let add = if stab.is_some() { " " } else { "" };
379 w.write_str(ITEM_TABLE_ROW_OPEN);
380 let id = match import.kind {
381 clean::ImportKind::Simple(s) => {
382 format!(" id=\"{}\"", cx.derive_id(format!("reexport.{}", s)))
384 clean::ImportKind::Glob => String::new(),
386 let stab_tags = stab_tags.unwrap_or_default();
387 let (stab_tags_before, stab_tags_after) = if stab_tags.is_empty() {
390 ("<div class=\"item-right docblock-short\">", "</div>")
394 "<div class=\"item-left {stab}{add}import-item\"{id}>\
395 <code>{vis}{imp}</code>\
397 {stab_tags_before}{stab_tags}{stab_tags_after}",
398 stab = stab.unwrap_or_default(),
399 vis = visibility_print_with_space(myitem.visibility(tcx), myitem.item_id, cx),
400 imp = import.print(cx),
402 w.write_str(ITEM_TABLE_ROW_CLOSE);
406 if myitem.name.is_none() {
410 let unsafety_flag = match *myitem.kind {
411 clean::FunctionItem(_) | clean::ForeignFunctionItem(_)
412 if myitem.fn_header(cx.tcx()).unwrap().unsafety
413 == hir::Unsafety::Unsafe =>
415 "<sup title=\"unsafe function\">⚠</sup>"
420 let stab = myitem.stability_class(cx.tcx());
421 let add = if stab.is_some() { " " } else { "" };
423 let visibility_emoji = match myitem.visibility(tcx) {
424 Some(ty::Visibility::Restricted(_)) => {
425 "<span title=\"Restricted Visibility\"> 🔒</span> "
430 let doc_value = myitem.doc_value().unwrap_or_default();
431 w.write_str(ITEM_TABLE_ROW_OPEN);
432 let docs = MarkdownSummaryLine(&doc_value, &myitem.links(cx)).into_string();
433 let (docs_before, docs_after) = if docs.is_empty() {
436 ("<div class=\"item-right docblock-short\">", "</div>")
440 "<div class=\"item-left {stab}{add}module-item\">\
441 <a class=\"{class}\" href=\"{href}\" title=\"{title}\">{name}</a>\
446 {docs_before}{docs}{docs_after}",
447 name = myitem.name.unwrap(),
448 visibility_emoji = visibility_emoji,
449 stab_tags = extra_info_tags(myitem, item, cx.tcx()),
450 class = myitem.type_(),
452 stab = stab.unwrap_or_default(),
453 unsafety_flag = unsafety_flag,
454 href = item_path(myitem.type_(), myitem.name.unwrap().as_str()),
455 title = [full_path(cx, myitem), myitem.type_().to_string()]
457 .filter_map(|s| if !s.is_empty() { Some(s.as_str()) } else { None })
461 w.write_str(ITEM_TABLE_ROW_CLOSE);
466 if last_section.is_some() {
467 w.write_str(ITEM_TABLE_CLOSE);
471 /// Render the stability, deprecation and portability tags that are displayed in the item's summary
472 /// at the module level.
473 fn extra_info_tags(item: &clean::Item, parent: &clean::Item, tcx: TyCtxt<'_>) -> String {
474 let mut tags = String::new();
476 fn tag_html(class: &str, title: &str, contents: &str) -> String {
477 format!(r#"<span class="stab {}" title="{}">{}</span>"#, class, Escape(title), contents)
480 // The trailing space after each tag is to space it properly against the rest of the docs.
481 if let Some(depr) = &item.deprecation(tcx) {
482 let mut message = "Deprecated";
483 if !stability::deprecation_in_effect(depr) {
484 message = "Deprecation planned";
486 tags += &tag_html("deprecated", "", message);
489 // The "rustc_private" crates are permanently unstable so it makes no sense
490 // to render "unstable" everywhere.
491 if item.stability(tcx).as_ref().map(|s| s.is_unstable() && s.feature != sym::rustc_private)
494 tags += &tag_html("unstable", "", "Experimental");
497 let cfg = match (&item.cfg, parent.cfg.as_ref()) {
498 (Some(cfg), Some(parent_cfg)) => cfg.simplify_with(parent_cfg),
499 (cfg, _) => cfg.as_deref().cloned(),
502 debug!("Portability name={:?} {:?} - {:?} = {:?}", item.name, item.cfg, parent.cfg, cfg);
503 if let Some(ref cfg) = cfg {
504 tags += &tag_html("portability", &cfg.render_long_plain(), &cfg.render_short_html());
510 fn item_function(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, f: &clean::Function) {
512 let header = it.fn_header(tcx).expect("printing a function which isn't a function");
513 let constness = print_constness_with_space(&header.constness, it.const_stability(tcx));
514 let unsafety = header.unsafety.print_with_space();
515 let abi = print_abi_with_space(header.abi).to_string();
516 let asyncness = header.asyncness.print_with_space();
517 let visibility = visibility_print_with_space(it.visibility(tcx), it.item_id, cx).to_string();
518 let name = it.name.unwrap();
520 let generics_len = format!("{:#}", f.generics.print(cx)).len();
521 let header_len = "fn ".len()
527 + name.as_str().len()
531 f.decl.output.as_return().and_then(|output| notable_traits_button(output, cx));
533 wrap_into_item_decl(w, |w| {
534 wrap_item(w, "fn", |w| {
535 render_attributes_in_pre(w, it, "");
536 w.reserve(header_len);
539 "{vis}{constness}{asyncness}{unsafety}{abi}fn \
540 {name}{generics}{decl}{notable_traits}{where_clause}",
542 constness = constness,
543 asyncness = asyncness,
547 generics = f.generics.print(cx),
548 where_clause = print_where_clause(&f.generics, cx, 0, Ending::Newline),
549 decl = f.decl.full_print(header_len, 0, cx),
550 notable_traits = notable_traits.unwrap_or_default(),
554 document(w, cx, it, None, HeadingOffset::H2);
557 fn item_trait(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean::Trait) {
559 let bounds = bounds(&t.bounds, false, cx);
560 let required_types = t.items.iter().filter(|m| m.is_ty_associated_type()).collect::<Vec<_>>();
561 let provided_types = t.items.iter().filter(|m| m.is_associated_type()).collect::<Vec<_>>();
562 let required_consts = t.items.iter().filter(|m| m.is_ty_associated_const()).collect::<Vec<_>>();
563 let provided_consts = t.items.iter().filter(|m| m.is_associated_const()).collect::<Vec<_>>();
564 let required_methods = t.items.iter().filter(|m| m.is_ty_method()).collect::<Vec<_>>();
565 let provided_methods = t.items.iter().filter(|m| m.is_method()).collect::<Vec<_>>();
566 let count_types = required_types.len() + provided_types.len();
567 let count_consts = required_consts.len() + provided_consts.len();
568 let count_methods = required_methods.len() + provided_methods.len();
569 let must_implement_one_of_functions = tcx.trait_def(t.def_id).must_implement_one_of.clone();
571 // Output the trait definition
572 wrap_into_item_decl(w, |w| {
573 wrap_item(w, "trait", |w| {
574 render_attributes_in_pre(w, it, "");
577 "{}{}{}trait {}{}{}",
578 visibility_print_with_space(it.visibility(tcx), it.item_id, cx),
579 t.unsafety(tcx).print_with_space(),
580 if t.is_auto(tcx) { "auto " } else { "" },
582 t.generics.print(cx),
586 if !t.generics.where_predicates.is_empty() {
587 write!(w, "{}", print_where_clause(&t.generics, cx, 0, Ending::Newline));
592 if t.items.is_empty() {
595 // FIXME: we should be using a derived_id for the Anchors here
597 let mut toggle = false;
599 // If there are too many associated types, hide _everything_
600 if should_hide_fields(count_types) {
605 "{} associated items",
606 count_types + count_consts + count_methods
610 for types in [&required_types, &provided_types] {
615 AssocItemLink::Anchor(None),
623 // If there are too many associated constants, hide everything after them
624 // We also do this if the types + consts is large because otherwise we could
625 // render a bunch of types and _then_ a bunch of consts just because both were
626 // _just_ under the limit
627 if !toggle && should_hide_fields(count_types + count_consts) {
632 "{} associated constant{} and {} method{}",
634 pluralize(count_consts),
636 pluralize(count_methods),
640 if count_types != 0 && (count_consts != 0 || count_methods != 0) {
643 for consts in [&required_consts, &provided_consts] {
648 AssocItemLink::Anchor(None),
656 if !toggle && should_hide_fields(count_methods) {
658 toggle_open(w, format_args!("{} methods", count_methods));
660 if count_consts != 0 && count_methods != 0 {
663 for (pos, m) in required_methods.iter().enumerate() {
667 AssocItemLink::Anchor(None),
674 if pos < required_methods.len() - 1 {
675 w.write_str("<span class=\"item-spacer\"></span>");
678 if !required_methods.is_empty() && !provided_methods.is_empty() {
681 for (pos, m) in provided_methods.iter().enumerate() {
685 AssocItemLink::Anchor(None),
691 clean::MethodItem(ref inner, _)
692 if !inner.generics.where_predicates.is_empty() =>
694 w.write_str(",\n { ... }\n");
697 w.write_str(" { ... }\n");
701 if pos < provided_methods.len() - 1 {
702 w.write_str("<span class=\"item-spacer\"></span>");
713 // Trait documentation
714 document(w, cx, it, None, HeadingOffset::H2);
716 fn write_small_section_header(w: &mut Buffer, id: &str, title: &str, extra_content: &str) {
719 "<h2 id=\"{0}\" class=\"small-section-header\">\
720 {1}<a href=\"#{0}\" class=\"anchor\">§</a>\
722 id, title, extra_content
726 fn trait_item(w: &mut Buffer, cx: &mut Context<'_>, m: &clean::Item, t: &clean::Item) {
727 let name = m.name.unwrap();
728 info!("Documenting {} on {:?}", name, t.name);
729 let item_type = m.type_();
730 let id = cx.derive_id(format!("{}.{}", item_type, name));
731 let mut content = Buffer::empty_from(w);
732 document(&mut content, cx, m, Some(t), HeadingOffset::H5);
733 let toggled = !content.is_empty();
735 write!(w, "<details class=\"rustdoc-toggle method-toggle\" open><summary>");
737 write!(w, "<section id=\"{}\" class=\"method has-srclink\">", id);
738 render_rightside(w, cx, m, t, RenderMode::Normal);
739 write!(w, "<h4 class=\"code-header\">");
743 AssocItemLink::Anchor(Some(&id)),
748 w.write_str("</h4>");
749 w.write_str("</section>");
751 write!(w, "</summary>");
752 w.push_buffer(content);
753 write!(w, "</details>");
757 if !required_types.is_empty() {
758 write_small_section_header(
760 "required-associated-types",
761 "Required Associated Types",
762 "<div class=\"methods\">",
764 for t in required_types {
765 trait_item(w, cx, t, it);
767 w.write_str("</div>");
769 if !provided_types.is_empty() {
770 write_small_section_header(
772 "provided-associated-types",
773 "Provided Associated Types",
774 "<div class=\"methods\">",
776 for t in provided_types {
777 trait_item(w, cx, t, it);
779 w.write_str("</div>");
782 if !required_consts.is_empty() {
783 write_small_section_header(
785 "required-associated-consts",
786 "Required Associated Constants",
787 "<div class=\"methods\">",
789 for t in required_consts {
790 trait_item(w, cx, t, it);
792 w.write_str("</div>");
794 if !provided_consts.is_empty() {
795 write_small_section_header(
797 "provided-associated-consts",
798 "Provided Associated Constants",
799 "<div class=\"methods\">",
801 for t in provided_consts {
802 trait_item(w, cx, t, it);
804 w.write_str("</div>");
807 // Output the documentation for each function individually
808 if !required_methods.is_empty() || must_implement_one_of_functions.is_some() {
809 write_small_section_header(
813 "<div class=\"methods\">",
816 if let Some(list) = must_implement_one_of_functions.as_deref() {
819 "<div class=\"stab must_implement\">At least one of the `{}` methods is required.</div>",
820 list.iter().join("`, `")
824 for m in required_methods {
825 trait_item(w, cx, m, it);
827 w.write_str("</div>");
829 if !provided_methods.is_empty() {
830 write_small_section_header(
834 "<div class=\"methods\">",
836 for m in provided_methods {
837 trait_item(w, cx, m, it);
839 w.write_str("</div>");
842 // If there are methods directly on this trait object, render them here.
843 render_assoc_items(w, cx, it, it.item_id.expect_def_id(), AssocItemRender::All);
845 let cloned_shared = Rc::clone(&cx.shared);
846 let cache = &cloned_shared.cache;
847 let mut extern_crates = FxHashSet::default();
848 if let Some(implementors) = cache.implementors.get(&it.item_id.expect_def_id()) {
849 // The DefId is for the first Type found with that name. The bool is
850 // if any Types with the same name but different DefId have been found.
851 let mut implementor_dups: FxHashMap<Symbol, (DefId, bool)> = FxHashMap::default();
852 for implementor in implementors {
853 if let Some(did) = implementor.inner_impl().for_.without_borrowed_ref().def_id(cache) &&
855 extern_crates.insert(did.krate);
857 match implementor.inner_impl().for_.without_borrowed_ref() {
858 clean::Type::Path { ref path } if !path.is_assoc_ty() => {
859 let did = path.def_id();
860 let &mut (prev_did, ref mut has_duplicates) =
861 implementor_dups.entry(path.last()).or_insert((did, false));
863 *has_duplicates = true;
870 let (local, foreign) =
871 implementors.iter().partition::<Vec<_>, _>(|i| i.is_on_local_type(cx));
873 let (mut synthetic, mut concrete): (Vec<&&Impl>, Vec<&&Impl>) =
874 local.iter().partition(|i| i.inner_impl().kind.is_auto());
876 synthetic.sort_by(|a, b| compare_impl(a, b, cx));
877 concrete.sort_by(|a, b| compare_impl(a, b, cx));
879 if !foreign.is_empty() {
880 write_small_section_header(w, "foreign-impls", "Implementations on Foreign Types", "");
882 for implementor in foreign {
883 let provided_methods = implementor.inner_impl().provided_trait_methods(cx.tcx());
885 AssocItemLink::GotoSource(implementor.impl_item.item_id, &provided_methods);
895 ImplRenderingParameters {
896 show_def_docs: false,
897 show_default_items: false,
898 show_non_assoc_items: true,
899 toggle_open_by_default: false,
905 write_small_section_header(
909 "<div id=\"implementors-list\">",
911 for implementor in concrete {
912 render_implementor(cx, implementor, it, w, &implementor_dups, &[]);
914 w.write_str("</div>");
916 if t.is_auto(cx.tcx()) {
917 write_small_section_header(
919 "synthetic-implementors",
921 "<div id=\"synthetic-implementors-list\">",
923 for implementor in synthetic {
930 &collect_paths_for_type(implementor.inner_impl().for_.clone(), cache),
933 w.write_str("</div>");
936 // even without any implementations to write in, we still want the heading and list, so the
937 // implementors javascript file pulled in below has somewhere to write the impls into
938 write_small_section_header(
942 "<div id=\"implementors-list\"></div>",
945 if t.is_auto(cx.tcx()) {
946 write_small_section_header(
948 "synthetic-implementors",
950 "<div id=\"synthetic-implementors-list\"></div>",
955 // Include implementors in crates that depend on the current crate.
957 // This is complicated by the way rustdoc is invoked, which is basically
958 // the same way rustc is invoked: it gets called, one at a time, for each
959 // crate. When building the rustdocs for the current crate, rustdoc can
960 // see crate metadata for its dependencies, but cannot see metadata for its
963 // To make this work, we generate a "hook" at this stage, and our
964 // dependents can "plug in" to it when they build. For simplicity's sake,
965 // it's [JSONP]: a JavaScript file with the data we need (and can parse),
966 // surrounded by a tiny wrapper that the Rust side ignores, but allows the
967 // JavaScript side to include without having to worry about Same Origin
968 // Policy. The code for *that* is in `write_shared.rs`.
970 // This is further complicated by `#[doc(inline)]`. We want all copies
971 // of an inlined trait to reference the same JS file, to address complex
972 // dependency graphs like this one (lower crates depend on higher crates):
975 // --------------------------------------------
976 // | crate A: trait Foo |
977 // --------------------------------------------
979 // -------------------------------- |
980 // | crate B: impl A::Foo for Bar | |
981 // -------------------------------- |
983 // ---------------------------------------------
984 // | crate C: #[doc(inline)] use A::Foo as Baz |
985 // | impl Baz for Quux |
986 // ---------------------------------------------
989 // Basically, we want `C::Baz` and `A::Foo` to show the same set of
990 // impls, which is easier if they both treat `/implementors/A/trait.Foo.js`
991 // as the Single Source of Truth.
993 // We also want the `impl Baz for Quux` to be written to
994 // `trait.Foo.js`. However, when we generate plain HTML for `C::Baz`,
995 // we're going to want to generate plain HTML for `impl Baz for Quux` too,
996 // because that'll load faster, and it's better for SEO. And we don't want
997 // the same impl to show up twice on the same page.
999 // To make this work, the implementors JS file has a structure kinda
1004 // "B": {"impl A::Foo for Bar"},
1005 // "C": {"impl Baz for Quux"},
1009 // First of all, this means we can rebuild a crate, and it'll replace its own
1010 // data if something changes. That is, `rustdoc` is idempotent. The other
1011 // advantage is that we can list the crates that get included in the HTML,
1012 // and ignore them when doing the JavaScript-based part of rendering.
1013 // So C's HTML will have something like this:
1016 // <script src="/implementors/A/trait.Foo.js"
1017 // data-ignore-extern-crates="A,B" async></script>
1020 // And, when the JS runs, anything in data-ignore-extern-crates is known
1021 // to already be in the HTML, and will be ignored.
1023 // [JSONP]: https://en.wikipedia.org/wiki/JSONP
1024 let mut js_src_path: UrlPartsBuilder = std::iter::repeat("..")
1025 .take(cx.current.len())
1026 .chain(std::iter::once("implementors"))
1028 if let Some(did) = it.item_id.as_def_id() &&
1029 let get_extern = { || cache.external_paths.get(&did).map(|s| s.0.clone()) } &&
1030 let Some(fqp) = cache.exact_paths.get(&did).cloned().or_else(get_extern) {
1031 js_src_path.extend(fqp[..fqp.len() - 1].iter().copied());
1032 js_src_path.push_fmt(format_args!("{}.{}.js", it.type_(), fqp.last().unwrap()));
1034 js_src_path.extend(cx.current.iter().copied());
1035 js_src_path.push_fmt(format_args!("{}.{}.js", it.type_(), it.name.unwrap()));
1037 let extern_crates = extern_crates
1039 .map(|cnum| tcx.crate_name(cnum).to_string())
1040 .collect::<Vec<_>>()
1042 let (extern_before, extern_after) =
1043 if extern_crates.is_empty() { ("", "") } else { (" data-ignore-extern-crates=\"", "\"") };
1046 "<script src=\"{src}\"{extern_before}{extern_crates}{extern_after} async></script>",
1047 src = js_src_path.finish(),
1051 fn item_trait_alias(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean::TraitAlias) {
1052 wrap_into_item_decl(w, |w| {
1053 wrap_item(w, "trait-alias", |w| {
1054 render_attributes_in_pre(w, it, "");
1057 "trait {}{}{} = {};",
1059 t.generics.print(cx),
1060 print_where_clause(&t.generics, cx, 0, Ending::Newline),
1061 bounds(&t.bounds, true, cx)
1066 document(w, cx, it, None, HeadingOffset::H2);
1068 // Render any items associated directly to this alias, as otherwise they
1069 // won't be visible anywhere in the docs. It would be nice to also show
1070 // associated items from the aliased type (see discussion in #32077), but
1071 // we need #14072 to make sense of the generics.
1072 render_assoc_items(w, cx, it, it.item_id.expect_def_id(), AssocItemRender::All)
1075 fn item_opaque_ty(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean::OpaqueTy) {
1076 wrap_into_item_decl(w, |w| {
1077 wrap_item(w, "opaque", |w| {
1078 render_attributes_in_pre(w, it, "");
1081 "type {}{}{where_clause} = impl {bounds};",
1083 t.generics.print(cx),
1084 where_clause = print_where_clause(&t.generics, cx, 0, Ending::Newline),
1085 bounds = bounds(&t.bounds, false, cx),
1090 document(w, cx, it, None, HeadingOffset::H2);
1092 // Render any items associated directly to this alias, as otherwise they
1093 // won't be visible anywhere in the docs. It would be nice to also show
1094 // associated items from the aliased type (see discussion in #32077), but
1095 // we need #14072 to make sense of the generics.
1096 render_assoc_items(w, cx, it, it.item_id.expect_def_id(), AssocItemRender::All)
1099 fn item_typedef(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean::Typedef) {
1100 fn write_content(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Typedef) {
1101 wrap_item(w, "typedef", |w| {
1102 render_attributes_in_pre(w, it, "");
1103 write!(w, "{}", visibility_print_with_space(it.visibility(cx.tcx()), it.item_id, cx));
1106 "type {}{}{where_clause} = {type_};",
1108 t.generics.print(cx),
1109 where_clause = print_where_clause(&t.generics, cx, 0, Ending::Newline),
1110 type_ = t.type_.print(cx),
1115 wrap_into_item_decl(w, |w| write_content(w, cx, it, t));
1117 document(w, cx, it, None, HeadingOffset::H2);
1119 let def_id = it.item_id.expect_def_id();
1120 // Render any items associated directly to this alias, as otherwise they
1121 // won't be visible anywhere in the docs. It would be nice to also show
1122 // associated items from the aliased type (see discussion in #32077), but
1123 // we need #14072 to make sense of the generics.
1124 render_assoc_items(w, cx, it, def_id, AssocItemRender::All);
1125 document_type_layout(w, cx, def_id);
1128 fn item_union(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, s: &clean::Union) {
1129 wrap_into_item_decl(w, |w| {
1130 wrap_item(w, "union", |w| {
1131 render_attributes_in_pre(w, it, "");
1132 render_union(w, it, Some(&s.generics), &s.fields, "", cx);
1136 document(w, cx, it, None, HeadingOffset::H2);
1141 .filter_map(|f| match *f.kind {
1142 clean::StructFieldItem(ref ty) => Some((f, ty)),
1146 if fields.peek().is_some() {
1149 "<h2 id=\"fields\" class=\"fields small-section-header\">\
1150 Fields<a href=\"#fields\" class=\"anchor\">§</a>\
1153 for (field, ty) in fields {
1154 let name = field.name.expect("union field name");
1155 let id = format!("{}.{}", ItemType::StructField, name);
1158 "<span id=\"{id}\" class=\"{shortty} small-section-header\">\
1159 <a href=\"#{id}\" class=\"anchor field\">§</a>\
1160 <code>{name}: {ty}</code>\
1164 shortty = ItemType::StructField,
1167 if let Some(stability_class) = field.stability_class(cx.tcx()) {
1168 write!(w, "<span class=\"stab {stab}\"></span>", stab = stability_class);
1170 document(w, cx, field, Some(it), HeadingOffset::H3);
1173 let def_id = it.item_id.expect_def_id();
1174 render_assoc_items(w, cx, it, def_id, AssocItemRender::All);
1175 document_type_layout(w, cx, def_id);
1178 fn print_tuple_struct_fields(w: &mut Buffer, cx: &Context<'_>, s: &[clean::Item]) {
1179 for (i, ty) in s.iter().enumerate() {
1181 w.write_str(", ");
1184 clean::StrippedItem(box clean::StructFieldItem(_)) => w.write_str("_"),
1185 clean::StructFieldItem(ref ty) => write!(w, "{}", ty.print(cx)),
1186 _ => unreachable!(),
1191 fn item_enum(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, e: &clean::Enum) {
1193 let count_variants = e.variants().count();
1194 wrap_into_item_decl(w, |w| {
1195 wrap_item(w, "enum", |w| {
1196 render_attributes_in_pre(w, it, "");
1200 visibility_print_with_space(it.visibility(tcx), it.item_id, cx),
1202 e.generics.print(cx),
1204 if !print_where_clause_and_check(w, &e.generics, cx) {
1205 // If there wasn't a `where` clause, we add a whitespace.
1209 let variants_stripped = e.has_stripped_entries();
1210 if count_variants == 0 && !variants_stripped {
1214 let toggle = should_hide_fields(count_variants);
1216 toggle_open(w, format_args!("{} variants", count_variants));
1218 for v in e.variants() {
1220 let name = v.name.unwrap();
1222 clean::VariantItem(ref var) => match var {
1223 // FIXME(#101337): Show discriminant
1224 clean::Variant::CLike(..) => write!(w, "{}", name),
1225 clean::Variant::Tuple(ref s) => {
1226 write!(w, "{}(", name);
1227 print_tuple_struct_fields(w, cx, s);
1230 clean::Variant::Struct(ref s) => {
1243 _ => unreachable!(),
1248 if variants_stripped {
1249 w.write_str(" // some variants omitted\n");
1259 document(w, cx, it, None, HeadingOffset::H2);
1261 if count_variants != 0 {
1264 "<h2 id=\"variants\" class=\"variants small-section-header\">\
1265 Variants{}<a href=\"#variants\" class=\"anchor\">§</a>\
1267 document_non_exhaustive_header(it)
1269 document_non_exhaustive(w, it);
1270 write!(w, "<div class=\"variants\">");
1271 for variant in e.variants() {
1272 let id = cx.derive_id(format!("{}.{}", ItemType::Variant, variant.name.unwrap()));
1275 "<section id=\"{id}\" class=\"variant\">\
1276 <a href=\"#{id}\" class=\"anchor\">§</a>",
1279 render_stability_since_raw_with_extra(
1281 variant.stable_since(tcx),
1282 variant.const_stability(tcx),
1283 it.stable_since(tcx),
1284 it.const_stable_since(tcx),
1287 write!(w, "<h3 class=\"code-header\">{name}", name = variant.name.unwrap());
1288 if let clean::VariantItem(clean::Variant::Tuple(ref s)) = *variant.kind {
1290 print_tuple_struct_fields(w, cx, s);
1293 w.write_str("</h3></section>");
1295 use crate::clean::Variant;
1297 let heading_and_fields = match &*variant.kind {
1298 clean::VariantItem(Variant::Struct(s)) => Some(("Fields", &s.fields)),
1299 // Documentation on tuple variant fields is rare, so to reduce noise we only emit
1300 // the section if at least one field is documented.
1301 clean::VariantItem(Variant::Tuple(fields))
1302 if fields.iter().any(|f| f.doc_value().is_some()) =>
1304 Some(("Tuple Fields", fields))
1309 if let Some((heading, fields)) = heading_and_fields {
1311 cx.derive_id(format!("{}.{}.fields", ItemType::Variant, variant.name.unwrap()));
1312 write!(w, "<div class=\"sub-variant\" id=\"{id}\">", id = variant_id);
1313 write!(w, "<h4>{heading}</h4>", heading = heading);
1314 document_non_exhaustive(w, variant);
1315 for field in fields {
1317 clean::StrippedItem(box clean::StructFieldItem(_)) => {}
1318 clean::StructFieldItem(ref ty) => {
1319 let id = cx.derive_id(format!(
1320 "variant.{}.field.{}",
1321 variant.name.unwrap(),
1326 "<div class=\"sub-variant-field\">\
1327 <span id=\"{id}\" class=\"small-section-header\">\
1328 <a href=\"#{id}\" class=\"anchor field\">§</a>\
1329 <code>{f}: {t}</code>\
1332 f = field.name.unwrap(),
1335 document(w, cx, field, Some(variant), HeadingOffset::H5);
1336 write!(w, "</div>");
1338 _ => unreachable!(),
1341 w.write_str("</div>");
1344 document(w, cx, variant, Some(it), HeadingOffset::H4);
1346 write!(w, "</div>");
1348 let def_id = it.item_id.expect_def_id();
1349 render_assoc_items(w, cx, it, def_id, AssocItemRender::All);
1350 document_type_layout(w, cx, def_id);
1353 fn item_macro(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean::Macro) {
1354 wrap_into_item_decl(w, |w| {
1355 highlight::render_macro_with_highlighting(&t.source, w);
1357 document(w, cx, it, None, HeadingOffset::H2)
1360 fn item_proc_macro(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, m: &clean::ProcMacro) {
1361 wrap_into_item_decl(w, |w| {
1362 let name = it.name.expect("proc-macros always have names");
1364 MacroKind::Bang => {
1365 wrap_item(w, "macro", |w| {
1366 write!(w, "{}!() {{ /* proc-macro */ }}", name);
1369 MacroKind::Attr => {
1370 wrap_item(w, "attr", |w| {
1371 write!(w, "#[{}]", name);
1374 MacroKind::Derive => {
1375 wrap_item(w, "derive", |w| {
1376 write!(w, "#[derive({})]", name);
1377 if !m.helpers.is_empty() {
1378 w.push_str("\n{\n");
1379 w.push_str(" // Attributes available to this derive:\n");
1380 for attr in &m.helpers {
1381 writeln!(w, " #[{}]", attr);
1389 document(w, cx, it, None, HeadingOffset::H2)
1392 fn item_primitive(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item) {
1393 let def_id = it.item_id.expect_def_id();
1394 document(w, cx, it, None, HeadingOffset::H2);
1395 if it.name.map(|n| n.as_str() != "reference").unwrap_or(false) {
1396 render_assoc_items(w, cx, it, def_id, AssocItemRender::All);
1398 // We handle the "reference" primitive type on its own because we only want to list
1399 // implementations on generic types.
1400 let shared = Rc::clone(&cx.shared);
1401 let (concrete, synthetic, blanket_impl) = get_filtered_impls_for_reference(&shared, it);
1403 render_all_impls(w, cx, it, &concrete, &synthetic, &blanket_impl);
1407 fn item_constant(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, c: &clean::Constant) {
1408 wrap_into_item_decl(w, |w| {
1409 wrap_item(w, "const", |w| {
1411 render_attributes_in_code(w, it);
1415 "{vis}const {name}: {typ}",
1416 vis = visibility_print_with_space(it.visibility(tcx), it.item_id, cx),
1417 name = it.name.unwrap(),
1418 typ = c.type_.print(cx),
1421 // FIXME: The code below now prints
1422 // ` = _; // 100i32`
1423 // if the expression is
1425 // which looks just wrong.
1430 let value = c.value(tcx);
1431 let is_literal = c.is_literal(tcx);
1432 let expr = c.expr(tcx);
1433 if value.is_some() || is_literal {
1434 write!(w, " = {expr};", expr = Escape(&expr));
1440 if let Some(value) = &value {
1441 let value_lowercase = value.to_lowercase();
1442 let expr_lowercase = expr.to_lowercase();
1444 if value_lowercase != expr_lowercase
1445 && value_lowercase.trim_end_matches("i32") != expr_lowercase
1447 write!(w, " // {value}", value = Escape(value));
1454 document(w, cx, it, None, HeadingOffset::H2)
1457 fn item_struct(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, s: &clean::Struct) {
1458 wrap_into_item_decl(w, |w| {
1459 wrap_item(w, "struct", |w| {
1460 render_attributes_in_code(w, it);
1461 render_struct(w, it, Some(&s.generics), s.ctor_kind, &s.fields, "", true, cx);
1465 document(w, cx, it, None, HeadingOffset::H2);
1470 .filter_map(|f| match *f.kind {
1471 clean::StructFieldItem(ref ty) => Some((f, ty)),
1475 if let None | Some(CtorKind::Fn) = s.ctor_kind {
1476 if fields.peek().is_some() {
1479 "<h2 id=\"fields\" class=\"fields small-section-header\">\
1480 {}{}<a href=\"#fields\" class=\"anchor\">§</a>\
1482 if s.ctor_kind.is_none() { "Fields" } else { "Tuple Fields" },
1483 document_non_exhaustive_header(it)
1485 document_non_exhaustive(w, it);
1486 for (index, (field, ty)) in fields.enumerate() {
1488 field.name.map_or_else(|| index.to_string(), |sym| sym.as_str().to_string());
1489 let id = cx.derive_id(format!("{}.{}", ItemType::StructField, field_name));
1492 "<span id=\"{id}\" class=\"{item_type} small-section-header\">\
1493 <a href=\"#{id}\" class=\"anchor field\">§</a>\
1494 <code>{name}: {ty}</code>\
1496 item_type = ItemType::StructField,
1501 document(w, cx, field, Some(it), HeadingOffset::H3);
1505 let def_id = it.item_id.expect_def_id();
1506 render_assoc_items(w, cx, it, def_id, AssocItemRender::All);
1507 document_type_layout(w, cx, def_id);
1510 fn item_static(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, s: &clean::Static) {
1511 wrap_into_item_decl(w, |w| {
1512 wrap_item(w, "static", |w| {
1513 render_attributes_in_code(w, it);
1516 "{vis}static {mutability}{name}: {typ}",
1517 vis = visibility_print_with_space(it.visibility(cx.tcx()), it.item_id, cx),
1518 mutability = s.mutability.print_with_space(),
1519 name = it.name.unwrap(),
1520 typ = s.type_.print(cx)
1524 document(w, cx, it, None, HeadingOffset::H2)
1527 fn item_foreign_type(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item) {
1528 wrap_into_item_decl(w, |w| {
1529 wrap_item(w, "foreigntype", |w| {
1530 w.write_str("extern {\n");
1531 render_attributes_in_code(w, it);
1535 visibility_print_with_space(it.visibility(cx.tcx()), it.item_id, cx),
1541 document(w, cx, it, None, HeadingOffset::H2);
1543 render_assoc_items(w, cx, it, it.item_id.expect_def_id(), AssocItemRender::All)
1546 fn item_keyword(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item) {
1547 document(w, cx, it, None, HeadingOffset::H2)
1550 /// Compare two strings treating multi-digit numbers as single units (i.e. natural sort order).
1551 pub(crate) fn compare_names(mut lhs: &str, mut rhs: &str) -> Ordering {
1552 /// Takes a non-numeric and a numeric part from the given &str.
1553 fn take_parts<'a>(s: &mut &'a str) -> (&'a str, &'a str) {
1554 let i = s.find(|c: char| c.is_ascii_digit());
1555 let (a, b) = s.split_at(i.unwrap_or(s.len()));
1556 let i = b.find(|c: char| !c.is_ascii_digit());
1557 let (b, c) = b.split_at(i.unwrap_or(b.len()));
1562 while !lhs.is_empty() || !rhs.is_empty() {
1563 let (la, lb) = take_parts(&mut lhs);
1564 let (ra, rb) = take_parts(&mut rhs);
1565 // First process the non-numeric part.
1567 Ordering::Equal => (),
1570 // Then process the numeric part, if both sides have one (and they fit in a u64).
1571 if let (Ok(ln), Ok(rn)) = (lb.parse::<u64>(), rb.parse::<u64>()) {
1573 Ordering::Equal => (),
1577 // Then process the numeric part again, but this time as strings.
1579 Ordering::Equal => (),
1587 pub(super) fn full_path(cx: &Context<'_>, item: &clean::Item) -> String {
1588 let mut s = join_with_double_colon(&cx.current);
1590 s.push_str(item.name.unwrap().as_str());
1594 pub(super) fn item_path(ty: ItemType, name: &str) -> String {
1596 ItemType::Module => format!("{}index.html", ensure_trailing_slash(name)),
1597 _ => format!("{}.{}.html", ty, name),
1601 fn bounds(t_bounds: &[clean::GenericBound], trait_alias: bool, cx: &Context<'_>) -> String {
1602 let mut bounds = String::new();
1603 if !t_bounds.is_empty() {
1605 bounds.push_str(": ");
1607 for (i, p) in t_bounds.iter().enumerate() {
1609 bounds.push_str(" + ");
1611 bounds.push_str(&p.print(cx).to_string());
1617 fn wrap_into_item_decl<F>(w: &mut Buffer, f: F)
1619 F: FnOnce(&mut Buffer),
1621 w.write_str("<div class=\"item-decl\">");
1623 w.write_str("</div>")
1626 fn wrap_item<F>(w: &mut Buffer, item_name: &str, f: F)
1628 F: FnOnce(&mut Buffer),
1630 w.write_fmt(format_args!("<pre class=\"rust {}\"><code>", item_name));
1632 w.write_str("</code></pre>");
1635 fn compare_impl<'a, 'b>(lhs: &'a &&Impl, rhs: &'b &&Impl, cx: &Context<'_>) -> Ordering {
1636 let lhss = format!("{}", lhs.inner_impl().print(false, cx));
1637 let rhss = format!("{}", rhs.inner_impl().print(false, cx));
1639 // lhs and rhs are formatted as HTML, which may be unnecessary
1640 compare_names(&lhss, &rhss)
1643 fn render_implementor(
1644 cx: &mut Context<'_>,
1646 trait_: &clean::Item,
1648 implementor_dups: &FxHashMap<Symbol, (DefId, bool)>,
1651 // If there's already another implementor that has the same abridged name, use the
1652 // full path, for example in `std::iter::ExactSizeIterator`
1653 let use_absolute = match implementor.inner_impl().for_ {
1654 clean::Type::Path { ref path, .. }
1655 | clean::BorrowedRef { type_: box clean::Type::Path { ref path, .. }, .. }
1656 if !path.is_assoc_ty() =>
1658 implementor_dups[&path.last()].1
1667 AssocItemLink::Anchor(None),
1671 ImplRenderingParameters {
1672 show_def_docs: false,
1673 show_default_items: false,
1674 show_non_assoc_items: false,
1675 toggle_open_by_default: false,
1683 g: Option<&clean::Generics>,
1684 fields: &[clean::Item],
1692 visibility_print_with_space(it.visibility(tcx), it.item_id, cx),
1696 let where_displayed = g
1698 write!(w, "{}", g.print(cx));
1699 print_where_clause_and_check(w, g, cx)
1703 // If there wasn't a `where` clause, we add a whitespace.
1704 if !where_displayed {
1708 write!(w, "{{\n{}", tab);
1710 fields.iter().filter(|f| matches!(*f.kind, clean::StructFieldItem(..))).count();
1711 let toggle = should_hide_fields(count_fields);
1713 toggle_open(w, format_args!("{} fields", count_fields));
1716 for field in fields {
1717 if let clean::StructFieldItem(ref ty) = *field.kind {
1721 visibility_print_with_space(field.visibility(tcx), field.item_id, cx),
1722 field.name.unwrap(),
1729 if it.has_stripped_entries().unwrap() {
1730 write!(w, " /* private fields */\n{}", tab);
1741 g: Option<&clean::Generics>,
1742 ty: Option<CtorKind>,
1743 fields: &[clean::Item],
1752 visibility_print_with_space(it.visibility(tcx), it.item_id, cx),
1753 if structhead { "struct " } else { "" },
1756 if let Some(g) = g {
1757 write!(w, "{}", g.print(cx))
1761 let where_diplayed = g.map(|g| print_where_clause_and_check(w, g, cx)).unwrap_or(false);
1763 // If there wasn't a `where` clause, we add a whitespace.
1764 if !where_diplayed {
1770 fields.iter().filter(|f| matches!(*f.kind, clean::StructFieldItem(..))).count();
1771 let has_visible_fields = count_fields > 0;
1772 let toggle = should_hide_fields(count_fields);
1774 toggle_open(w, format_args!("{} fields", count_fields));
1776 for field in fields {
1777 if let clean::StructFieldItem(ref ty) = *field.kind {
1782 visibility_print_with_space(field.visibility(tcx), field.item_id, cx),
1783 field.name.unwrap(),
1789 if has_visible_fields {
1790 if it.has_stripped_entries().unwrap() {
1791 write!(w, "\n{} /* private fields */", tab);
1793 write!(w, "\n{}", tab);
1794 } else if it.has_stripped_entries().unwrap() {
1795 write!(w, " /* private fields */ ");
1802 Some(CtorKind::Fn) => {
1804 for (i, field) in fields.iter().enumerate() {
1809 clean::StrippedItem(box clean::StructFieldItem(..)) => write!(w, "_"),
1810 clean::StructFieldItem(ref ty) => {
1814 visibility_print_with_space(field.visibility(tcx), field.item_id, cx),
1818 _ => unreachable!(),
1822 if let Some(g) = g {
1823 write!(w, "{}", print_where_clause(g, cx, 0, Ending::NoNewline));
1825 // We only want a ";" when we are displaying a tuple struct, not a variant tuple struct.
1830 Some(CtorKind::Const) => {
1831 // Needed for PhantomData.
1832 if let Some(g) = g {
1833 write!(w, "{}", print_where_clause(g, cx, 0, Ending::NoNewline));
1840 fn document_non_exhaustive_header(item: &clean::Item) -> &str {
1841 if item.is_non_exhaustive() { " (Non-exhaustive)" } else { "" }
1844 fn document_non_exhaustive(w: &mut Buffer, item: &clean::Item) {
1845 if item.is_non_exhaustive() {
1848 "<details class=\"rustdoc-toggle non-exhaustive\">\
1849 <summary class=\"hideme\"><span>{}</span></summary>\
1850 <div class=\"docblock\">",
1852 if item.is_struct() {
1853 "This struct is marked as non-exhaustive"
1854 } else if item.is_enum() {
1855 "This enum is marked as non-exhaustive"
1856 } else if item.is_variant() {
1857 "This variant is marked as non-exhaustive"
1859 "This type is marked as non-exhaustive"
1864 if item.is_struct() {
1866 "Non-exhaustive structs could have additional fields added in future. \
1867 Therefore, non-exhaustive structs cannot be constructed in external crates \
1868 using the traditional <code>Struct { .. }</code> syntax; cannot be \
1869 matched against without a wildcard <code>..</code>; and \
1870 struct update syntax will not work.",
1872 } else if item.is_enum() {
1874 "Non-exhaustive enums could have additional variants added in future. \
1875 Therefore, when matching against variants of non-exhaustive enums, an \
1876 extra wildcard arm must be added to account for any future variants.",
1878 } else if item.is_variant() {
1880 "Non-exhaustive enum variants could have additional fields added in future. \
1881 Therefore, non-exhaustive enum variants cannot be constructed in external \
1882 crates and cannot be matched against.",
1886 "This type will require a wildcard arm in any match statements or constructors.",
1890 w.write_str("</div></details>");
1894 fn document_type_layout(w: &mut Buffer, cx: &Context<'_>, ty_def_id: DefId) {
1895 fn write_size_of_layout(w: &mut Buffer, layout: &LayoutS<VariantIdx>, tag_size: u64) {
1896 if layout.abi.is_unsized() {
1897 write!(w, "(unsized)");
1899 let bytes = layout.size.bytes() - tag_size;
1900 write!(w, "{size} byte{pl}", size = bytes, pl = if bytes == 1 { "" } else { "s" },);
1904 if !cx.shared.show_type_layout {
1910 "<h2 id=\"layout\" class=\"small-section-header\"> \
1911 Layout<a href=\"#layout\" class=\"anchor\">§</a></h2>"
1913 writeln!(w, "<div class=\"docblock\">");
1916 let param_env = tcx.param_env(ty_def_id);
1917 let ty = tcx.type_of(ty_def_id);
1918 match tcx.layout_of(param_env.and(ty)) {
1922 "<div class=\"warning\"><p><strong>Note:</strong> Most layout information is \
1923 <strong>completely unstable</strong> and may even differ between compilations. \
1924 The only exception is types with certain <code>repr(...)</code> attributes. \
1925 Please see the Rust Reference’s \
1926 <a href=\"https://doc.rust-lang.org/reference/type-layout.html\">“Type Layout”</a> \
1927 chapter for details on type layout guarantees.</p></div>"
1929 w.write_str("<p><strong>Size:</strong> ");
1930 write_size_of_layout(w, &ty_layout.layout.0, 0);
1931 writeln!(w, "</p>");
1932 if let Variants::Multiple { variants, tag, tag_encoding, .. } =
1933 &ty_layout.layout.variants()
1935 if !variants.is_empty() {
1937 "<p><strong>Size for each variant:</strong></p>\
1941 let Adt(adt, _) = ty_layout.ty.kind() else {
1942 span_bug!(tcx.def_span(ty_def_id), "not an adt")
1945 let tag_size = if let TagEncoding::Niche { .. } = tag_encoding {
1947 } else if let Primitive::Int(i, _) = tag.primitive() {
1950 span_bug!(tcx.def_span(ty_def_id), "tag is neither niche nor int")
1953 for (index, layout) in variants.iter_enumerated() {
1954 let name = adt.variant(index).name;
1955 write!(w, "<li><code>{name}</code>: ", name = name);
1956 write_size_of_layout(w, layout, tag_size);
1957 writeln!(w, "</li>");
1959 w.write_str("</ul>");
1963 // This kind of layout error can occur with valid code, e.g. if you try to
1964 // get the layout of a generic type such as `Vec<T>`.
1965 Err(LayoutError::Unknown(_)) => {
1968 "<p><strong>Note:</strong> Unable to compute type layout, \
1969 possibly due to this type having generic parameters. \
1970 Layout can only be computed for concrete, fully-instantiated types.</p>"
1973 // This kind of error probably can't happen with valid code, but we don't
1974 // want to panic and prevent the docs from building, so we just let the
1975 // user know that we couldn't compute the layout.
1976 Err(LayoutError::SizeOverflow(_)) => {
1979 "<p><strong>Note:</strong> Encountered an error during type layout; \
1980 the type was too big.</p>"
1983 Err(LayoutError::NormalizationFailure(_, _)) => {
1986 "<p><strong>Note:</strong> Encountered an error during type layout; \
1987 the type failed to be normalized.</p>"
1992 writeln!(w, "</div>");
1995 fn pluralize(count: usize) -> &'static str {
1996 if count > 1 { "s" } else { "" }