Auto merge of #73767 - P1n3appl3:rustdoc-formats, r=tmandry

Refactor librustdoc html backend

This PR moves several types out of the librustdoc::html module so that they can be used by a future json backend. These changes are a re-implementation of [some work done 6 months ago](https://github.com/rust-lang/rust/compare/master...GuillaumeGomez:multiple-output-formats) by @GuillaumeGomez. I'm currently working on said json backend and will put up an RFC soon with the proposed implementation.

There are a couple of changes that are more substantial than relocating structs to a different module:
1. The `Cache` is no longer part of the `html::render::Context` type and therefor it needs to be explicitly passed to any functions that access it.
2. The driving function `html::render::run` has been rewritten to use the `FormatRenderer` trait which should allow different backends to re-use the driving code.

r? @GuillaumeGomez

cc @tmandry @betamos

2 files changed, 4601 insertions, 488 deletions

diff --git a/src/librustdoc/html/render/cache.rs b/src/librustdoc/html/render/cache.rs
index 1b5c8a9378e..378efa1a1be 100644
--- a/src/librustdoc/html/render/cache.rs
+++ b/src/librustdoc/html/render/cache.rs
@@ -1,18 +1,16 @@
-use crate::clean::{self, AttributesExt, GetDefId};
-use crate::fold::DocFolder;
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
-use rustc_hir::def_id::{CrateNum, DefId, CRATE_DEF_INDEX};
-use rustc_middle::middle::privacy::AccessLevels;
-use rustc_span::source_map::FileName;
-use rustc_span::symbol::sym;
 use std::collections::BTreeMap;
-use std::mem;
-use std::path::{Path, PathBuf};
+use std::path::Path;
 
+use rustc_data_structures::fx::FxHashMap;
+use rustc_span::symbol::sym;
 use serde::Serialize;
 
-use super::{plain_summary_line, shorten, Impl, IndexItem, IndexItemFunctionType, ItemType};
-use super::{Generic, RenderInfo, RenderType, TypeWithKind};
+use crate::clean::types::GetDefId;
+use crate::clean::{self, AttributesExt};
+use crate::formats::cache::Cache;
+use crate::formats::item_type::ItemType;
+use crate::html::render::{plain_summary_line, shorten};
+use crate::html::render::{Generic, IndexItem, IndexItemFunctionType, RenderType, TypeWithKind};
 
 /// Indicates where an external crate can be found.
 pub enum ExternalLocation {
@@ -24,483 +22,9 @@ pub enum ExternalLocation {
     Unknown,
 }
 
-/// This cache is used to store information about the `clean::Crate` being
-/// rendered in order to provide more useful documentation. This contains
-/// information like all implementors of a trait, all traits a type implements,
-/// documentation for all known traits, etc.
-///
-/// This structure purposefully does not implement `Clone` because it's intended
-/// to be a fairly large and expensive structure to clone. Instead this adheres
-/// to `Send` so it may be stored in a `Arc` instance and shared among the various
-/// rendering threads.
-#[derive(Default)]
-crate struct Cache {
-    /// Maps a type ID to all known implementations for that type. This is only
-    /// recognized for intra-crate `ResolvedPath` types, and is used to print
-    /// out extra documentation on the page of an enum/struct.
-    ///
-    /// The values of the map are a list of implementations and documentation
-    /// found on that implementation.
-    pub impls: FxHashMap<DefId, Vec<Impl>>,
-
-    /// Maintains a mapping of local crate `DefId`s to the fully qualified name
-    /// and "short type description" of that node. This is used when generating
-    /// URLs when a type is being linked to. External paths are not located in
-    /// this map because the `External` type itself has all the information
-    /// necessary.
-    pub paths: FxHashMap<DefId, (Vec<String>, ItemType)>,
-
-    /// Similar to `paths`, but only holds external paths. This is only used for
-    /// generating explicit hyperlinks to other crates.
-    pub external_paths: FxHashMap<DefId, (Vec<String>, ItemType)>,
-
-    /// Maps local `DefId`s of exported types to fully qualified paths.
-    /// Unlike 'paths', this mapping ignores any renames that occur
-    /// due to 'use' statements.
-    ///
-    /// This map is used when writing out the special 'implementors'
-    /// javascript file. By using the exact path that the type
-    /// is declared with, we ensure that each path will be identical
-    /// to the path used if the corresponding type is inlined. By
-    /// doing this, we can detect duplicate impls on a trait page, and only display
-    /// the impl for the inlined type.
-    pub exact_paths: FxHashMap<DefId, Vec<String>>,
-
-    /// This map contains information about all known traits of this crate.
-    /// Implementations of a crate should inherit the documentation of the
-    /// parent trait if no extra documentation is specified, and default methods
-    /// should show up in documentation about trait implementations.
-    pub traits: FxHashMap<DefId, clean::Trait>,
-
-    /// When rendering traits, it's often useful to be able to list all
-    /// implementors of the trait, and this mapping is exactly, that: a mapping
-    /// of trait ids to the list of known implementors of the trait
-    pub implementors: FxHashMap<DefId, Vec<Impl>>,
-
-    /// Cache of where external crate documentation can be found.
-    pub extern_locations: FxHashMap<CrateNum, (String, PathBuf, ExternalLocation)>,
-
-    /// Cache of where documentation for primitives can be found.
-    pub primitive_locations: FxHashMap<clean::PrimitiveType, DefId>,
-
-    // Note that external items for which `doc(hidden)` applies to are shown as
-    // non-reachable while local items aren't. This is because we're reusing
-    // the access levels from the privacy check pass.
-    pub access_levels: AccessLevels<DefId>,
-
-    /// The version of the crate being documented, if given from the `--crate-version` flag.
-    pub crate_version: Option<String>,
-
-    /// Whether to document private items.
-    /// This is stored in `Cache` so it doesn't need to be passed through all rustdoc functions.
-    pub document_private: bool,
-
-    // Private fields only used when initially crawling a crate to build a cache
-    stack: Vec<String>,
-    parent_stack: Vec<DefId>,
-    parent_is_trait_impl: bool,
-    search_index: Vec<IndexItem>,
-    stripped_mod: bool,
-    pub deref_trait_did: Option<DefId>,
-    pub deref_mut_trait_did: Option<DefId>,
-    pub owned_box_did: Option<DefId>,
-    masked_crates: FxHashSet<CrateNum>,
-
-    // In rare case where a structure is defined in one module but implemented
-    // in another, if the implementing module is parsed before defining module,
-    // then the fully qualified name of the structure isn't presented in `paths`
-    // yet when its implementation methods are being indexed. Caches such methods
-    // and their parent id here and indexes them at the end of crate parsing.
-    orphan_impl_items: Vec<(DefId, clean::Item)>,
-
-    // Similarly to `orphan_impl_items`, sometimes trait impls are picked up
-    // even though the trait itself is not exported. This can happen if a trait
-    // was defined in function/expression scope, since the impl will be picked
-    // up by `collect-trait-impls` but the trait won't be scraped out in the HIR
-    // crawl. In order to prevent crashes when looking for spotlight traits or
-    // when gathering trait documentation on a type, hold impls here while
-    // folding and add them to the cache later on if we find the trait.
-    orphan_trait_impls: Vec<(DefId, FxHashSet<DefId>, Impl)>,
-
-    /// Aliases added through `#[doc(alias = "...")]`. Since a few items can have the same alias,
-    /// we need the alias element to have an array of items.
-    pub(super) aliases: BTreeMap<String, Vec<usize>>,
-}
-
-impl Cache {
-    pub fn from_krate(
-        renderinfo: RenderInfo,
-        document_private: bool,
-        extern_html_root_urls: &BTreeMap<String, String>,
-        dst: &Path,
-        mut krate: clean::Crate,
-    ) -> (clean::Crate, String, Cache) {
-        // Crawl the crate to build various caches used for the output
-        let RenderInfo {
-            inlined: _,
-            external_paths,
-            exact_paths,
-            access_levels,
-            deref_trait_did,
-            deref_mut_trait_did,
-            owned_box_did,
-            ..
-        } = renderinfo;
-
-        let external_paths =
-            external_paths.into_iter().map(|(k, (v, t))| (k, (v, ItemType::from(t)))).collect();
-
-        let mut cache = Cache {
-            impls: Default::default(),
-            external_paths,
-            exact_paths,
-            paths: Default::default(),
-            implementors: Default::default(),
-            stack: Vec::new(),
-            parent_stack: Vec::new(),
-            search_index: Vec::new(),
-            parent_is_trait_impl: false,
-            extern_locations: Default::default(),
-            primitive_locations: Default::default(),
-            stripped_mod: false,
-            access_levels,
-            crate_version: krate.version.take(),
-            document_private,
-            orphan_impl_items: Vec::new(),
-            orphan_trait_impls: Vec::new(),
-            traits: krate.external_traits.replace(Default::default()),
-            deref_trait_did,
-            deref_mut_trait_did,
-            owned_box_did,
-            masked_crates: mem::take(&mut krate.masked_crates),
-            aliases: Default::default(),
-        };
-
-        // Cache where all our extern crates are located
-        for &(n, ref e) in &krate.externs {
-            let src_root = match e.src {
-                FileName::Real(ref p) => match p.local_path().parent() {
-                    Some(p) => p.to_path_buf(),
-                    None => PathBuf::new(),
-                },
-                _ => PathBuf::new(),
-            };
-            let extern_url = extern_html_root_urls.get(&e.name).map(|u| &**u);
-            cache
-                .extern_locations
-                .insert(n, (e.name.clone(), src_root, extern_location(e, extern_url, &dst)));
-
-            let did = DefId { krate: n, index: CRATE_DEF_INDEX };
-            cache.external_paths.insert(did, (vec![e.name.to_string()], ItemType::Module));
-        }
-
-        // Cache where all known primitives have their documentation located.
-        //
-        // Favor linking to as local extern as possible, so iterate all crates in
-        // reverse topological order.
-        for &(_, ref e) in krate.externs.iter().rev() {
-            for &(def_id, prim, _) in &e.primitives {
-                cache.primitive_locations.insert(prim, def_id);
-            }
-        }
-        for &(def_id, prim, _) in &krate.primitives {
-            cache.primitive_locations.insert(prim, def_id);
-        }
-
-        cache.stack.push(krate.name.clone());
-        krate = cache.fold_crate(krate);
-
-        for (trait_did, dids, impl_) in cache.orphan_trait_impls.drain(..) {
-            if cache.traits.contains_key(&trait_did) {
-                for did in dids {
-                    cache.impls.entry(did).or_insert(vec![]).push(impl_.clone());
-                }
-            }
-        }
-
-        // Build our search index
-        let index = build_index(&krate, &mut cache);
-
-        (krate, index, cache)
-    }
-}
-
-impl DocFolder for Cache {
-    fn fold_item(&mut self, item: clean::Item) -> Option<clean::Item> {
-        if item.def_id.is_local() {
-            debug!("folding {} \"{:?}\", id {:?}", item.type_(), item.name, item.def_id);
-        }
-
-        // If this is a stripped module,
-        // we don't want it or its children in the search index.
-        let orig_stripped_mod = match item.inner {
-            clean::StrippedItem(box clean::ModuleItem(..)) => {
-                mem::replace(&mut self.stripped_mod, true)
-            }
-            _ => self.stripped_mod,
-        };
-
-        // If the impl is from a masked crate or references something from a
-        // masked crate then remove it completely.
-        if let clean::ImplItem(ref i) = item.inner {
-            if self.masked_crates.contains(&item.def_id.krate)
-                || i.trait_.def_id().map_or(false, |d| self.masked_crates.contains(&d.krate))
-                || i.for_.def_id().map_or(false, |d| self.masked_crates.contains(&d.krate))
-            {
-                return None;
-            }
-        }
-
-        // Propagate a trait method's documentation to all implementors of the
-        // trait.
-        if let clean::TraitItem(ref t) = item.inner {
-            self.traits.entry(item.def_id).or_insert_with(|| t.clone());
-        }
-
-        // Collect all the implementors of traits.
-        if let clean::ImplItem(ref i) = item.inner {
-            if let Some(did) = i.trait_.def_id() {
-                if i.blanket_impl.is_none() {
-                    self.implementors
-                        .entry(did)
-                        .or_default()
-                        .push(Impl { impl_item: item.clone() });
-                }
-            }
-        }
-
-        // Index this method for searching later on.
-        if let Some(ref s) = item.name {
-            let (parent, is_inherent_impl_item) = match item.inner {
-                clean::StrippedItem(..) => ((None, None), false),
-                clean::AssocConstItem(..) | clean::TypedefItem(_, true)
-                    if self.parent_is_trait_impl =>
-                {
-                    // skip associated items in trait impls
-                    ((None, None), false)
-                }
-                clean::AssocTypeItem(..)
-                | clean::TyMethodItem(..)
-                | clean::StructFieldItem(..)
-                | clean::VariantItem(..) => (
-                    (
-                        Some(*self.parent_stack.last().expect("parent_stack is empty")),
-                        Some(&self.stack[..self.stack.len() - 1]),
-                    ),
-                    false,
-                ),
-                clean::MethodItem(..) | clean::AssocConstItem(..) => {
-                    if self.parent_stack.is_empty() {
-                        ((None, None), false)
-                    } else {
-                        let last = self.parent_stack.last().expect("parent_stack is empty 2");
-                        let did = *last;
-                        let path = match self.paths.get(&did) {
-                            // The current stack not necessarily has correlation
-                            // for where the type was defined. On the other
-                            // hand, `paths` always has the right
-                            // information if present.
-                            Some(&(
-                                ref fqp,
-                                ItemType::Trait
-                                | ItemType::Struct
-                                | ItemType::Union
-                                | ItemType::Enum,
-                            )) => Some(&fqp[..fqp.len() - 1]),
-                            Some(..) => Some(&*self.stack),
-                            None => None,
-                        };
-                        ((Some(*last), path), true)
-                    }
-                }
-                _ => ((None, Some(&*self.stack)), false),
-            };
-
-            match parent {
-                (parent, Some(path)) if is_inherent_impl_item || !self.stripped_mod => {
-                    debug_assert!(!item.is_stripped());
-
-                    // A crate has a module at its root, containing all items,
-                    // which should not be indexed. The crate-item itself is
-                    // inserted later on when serializing the search-index.
-                    if item.def_id.index != CRATE_DEF_INDEX {
-                        self.search_index.push(IndexItem {
-                            ty: item.type_(),
-                            name: s.to_string(),
-                            path: path.join("::"),
-                            desc: shorten(plain_summary_line(item.doc_value())),
-                            parent,
-                            parent_idx: None,
-                            search_type: get_index_search_type(&item),
-                        });
-
-                        for alias in item.attrs.get_doc_aliases() {
-                            self.aliases
-                                .entry(alias.to_lowercase())
-                                .or_insert(Vec::new())
-                                .push(self.search_index.len() - 1);
-                        }
-                    }
-                }
-                (Some(parent), None) if is_inherent_impl_item => {
-                    // We have a parent, but we don't know where they're
-                    // defined yet. Wait for later to index this item.
-                    self.orphan_impl_items.push((parent, item.clone()));
-                }
-                _ => {}
-            }
-        }
-
-        // Keep track of the fully qualified path for this item.
-        let pushed = match item.name {
-            Some(ref n) if !n.is_empty() => {
-                self.stack.push(n.to_string());
-                true
-            }
-            _ => false,
-        };
-
-        match item.inner {
-            clean::StructItem(..)
-            | clean::EnumItem(..)
-            | clean::TypedefItem(..)
-            | clean::TraitItem(..)
-            | clean::FunctionItem(..)
-            | clean::ModuleItem(..)
-            | clean::ForeignFunctionItem(..)
-            | clean::ForeignStaticItem(..)
-            | clean::ConstantItem(..)
-            | clean::StaticItem(..)
-            | clean::UnionItem(..)
-            | clean::ForeignTypeItem
-            | clean::MacroItem(..)
-            | clean::ProcMacroItem(..)
-            | clean::VariantItem(..)
-                if !self.stripped_mod =>
-            {
-                // Re-exported items mean that the same id can show up twice
-                // in the rustdoc ast that we're looking at. We know,
-                // however, that a re-exported item doesn't show up in the
-                // `public_items` map, so we can skip inserting into the
-                // paths map if there was already an entry present and we're
-                // not a public item.
-                if !self.paths.contains_key(&item.def_id)
-                    || self.access_levels.is_public(item.def_id)
-                {
-                    self.paths.insert(item.def_id, (self.stack.clone(), item.type_()));
-                }
-            }
-            clean::PrimitiveItem(..) => {
-                self.paths.insert(item.def_id, (self.stack.clone(), item.type_()));
-            }
-
-            _ => {}
-        }
-
-        // Maintain the parent stack
-        let orig_parent_is_trait_impl = self.parent_is_trait_impl;
-        let parent_pushed = match item.inner {
-            clean::TraitItem(..)
-            | clean::EnumItem(..)
-            | clean::ForeignTypeItem
-            | clean::StructItem(..)
-            | clean::UnionItem(..)
-            | clean::VariantItem(..) => {
-                self.parent_stack.push(item.def_id);
-                self.parent_is_trait_impl = false;
-                true
-            }
-            clean::ImplItem(ref i) => {
-                self.parent_is_trait_impl = i.trait_.is_some();
-                match i.for_ {
-                    clean::ResolvedPath { did, .. } => {
-                        self.parent_stack.push(did);
-                        true
-                    }
-                    ref t => {
-                        let prim_did = t
-                            .primitive_type()
-                            .and_then(|t| self.primitive_locations.get(&t).cloned());
-                        match prim_did {
-                            Some(did) => {
-                                self.parent_stack.push(did);
-                                true
-                            }
-                            None => false,
-                        }
-                    }
-                }
-            }
-            _ => false,
-        };
-
-        // Once we've recursively found all the generics, hoard off all the
-        // implementations elsewhere.
-        let ret = self.fold_item_recur(item).and_then(|item| {
-            if let clean::Item { inner: clean::ImplItem(_), .. } = item {
-                // Figure out the id of this impl. This may map to a
-                // primitive rather than always to a struct/enum.
-                // Note: matching twice to restrict the lifetime of the `i` borrow.
-                let mut dids = FxHashSet::default();
-                if let clean::Item { inner: clean::ImplItem(ref i), .. } = item {
-                    match i.for_ {
-                        clean::ResolvedPath { did, .. }
-                        | clean::BorrowedRef {
-                            type_: box clean::ResolvedPath { did, .. }, ..
-                        } => {
-                            dids.insert(did);
-                        }
-                        ref t => {
-                            let did = t
-                                .primitive_type()
-                                .and_then(|t| self.primitive_locations.get(&t).cloned());
-
-                            if let Some(did) = did {
-                                dids.insert(did);
-                            }
-                        }
-                    }
-
-                    if let Some(generics) = i.trait_.as_ref().and_then(|t| t.generics()) {
-                        for bound in generics {
-                            if let Some(did) = bound.def_id() {
-                                dids.insert(did);
-                            }
-                        }
-                    }
-                } else {
-                    unreachable!()
-                };
-                let impl_item = Impl { impl_item: item };
-                if impl_item.trait_did().map_or(true, |d| self.traits.contains_key(&d)) {
-                    for did in dids {
-                        self.impls.entry(did).or_insert(vec![]).push(impl_item.clone());
-                    }
-                } else {
-                    let trait_did = impl_item.trait_did().expect("no trait did");
-                    self.orphan_trait_impls.push((trait_did, dids, impl_item));
-                }
-                None
-            } else {
-                Some(item)
-            }
-        });
-
-        if pushed {
-            self.stack.pop().expect("stack already empty");
-        }
-        if parent_pushed {
-            self.parent_stack.pop().expect("parent stack already empty");
-        }
-        self.stripped_mod = orig_stripped_mod;
-        self.parent_is_trait_impl = orig_parent_is_trait_impl;
-        ret
-    }
-}
-
 /// Attempts to find where an external crate is located, given that we're
 /// rendering in to the specified source destination.
-fn extern_location(
+pub fn extern_location(
     e: &clean::ExternalCrate,
     extern_url: Option<&str>,
     dst: &Path,
@@ -538,7 +62,7 @@ fn extern_location(
 }
 
 /// Builds the search index from the collected metadata
-fn build_index(krate: &clean::Crate, cache: &mut Cache) -> String {
+pub fn build_index(krate: &clean::Crate, cache: &mut Cache) -> String {
     let mut defid_to_pathid = FxHashMap::default();
     let mut crate_items = Vec::with_capacity(cache.search_index.len());
     let mut crate_paths = vec![];
@@ -640,7 +164,7 @@ fn build_index(krate: &clean::Crate, cache: &mut Cache) -> String {
     )
 }
 
-fn get_index_search_type(item: &clean::Item) -> Option<IndexItemFunctionType> {
+crate fn get_index_search_type(item: &clean::Item) -> Option<IndexItemFunctionType> {
     let (all_types, ret_types) = match item.inner {
         clean::FunctionItem(ref f) => (&f.all_types, &f.ret_types),
         clean::MethodItem(ref m) => (&m.all_types, &m.ret_types),
diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
new file mode 100644
index 00000000000..5fb2d9f6f91
--- /dev/null
+++ b/src/librustdoc/html/render/mod.rs
@@ -0,0 +1,4589 @@
+// ignore-tidy-filelength
+
+//! Rustdoc's HTML rendering module.
+//!
+//! This modules contains the bulk of the logic necessary for rendering a
+//! rustdoc `clean::Crate` instance to a set of static HTML pages. This
+//! rendering process is largely driven by the `format!` syntax extension to
+//! perform all I/O into files and streams.
+//!
+//! The rendering process is largely driven by the `Context` and `Cache`
+//! structures. The cache is pre-populated by crawling the crate in question,
+//! and then it is shared among the various rendering threads. The cache is meant
+//! to be a fairly large structure not implementing `Clone` (because it's shared
+//! among threads). The context, however, should be a lightweight structure. This
+//! is cloned per-thread and contains information about what is currently being
+//! rendered.
+//!
+//! In order to speed up rendering (mostly because of markdown rendering), the
+//! rendering process has been parallelized. This parallelization is only
+//! exposed through the `crate` method on the context, and then also from the
+//! fact that the shared cache is stored in TLS (and must be accessed as such).
+//!
+//! In addition to rendering the crate itself, this module is also responsible
+//! for creating the corresponding search index and source file renderings.
+//! These threads are not parallelized (they haven't been a bottleneck yet), and
+//! both occur before the crate is rendered.
+
+pub mod cache;
+
+#[cfg(test)]
+mod tests;
+
+use std::borrow::Cow;
+use std::cell::{Cell, RefCell};
+use std::cmp::Ordering;
+use std::collections::{BTreeMap, VecDeque};
+use std::default::Default;
+use std::ffi::OsStr;
+use std::fmt::{self, Write};
+use std::fs::{self, File};
+use std::io::prelude::*;
+use std::io::{self, BufReader};
+use std::path::{Component, Path, PathBuf};
+use std::rc::Rc;
+use std::str;
+use std::string::ToString;
+use std::sync::mpsc::{channel, Receiver};
+use std::sync::Arc;
+
+use itertools::Itertools;
+use rustc_ast_pretty::pprust;
+use rustc_data_structures::flock;
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_feature::UnstableFeatures;
+use rustc_hir as hir;
+use rustc_hir::def_id::{DefId, LOCAL_CRATE};
+use rustc_hir::Mutability;
+use rustc_middle::middle::stability;
+use rustc_span::edition::Edition;
+use rustc_span::hygiene::MacroKind;
+use rustc_span::source_map::FileName;
+use rustc_span::symbol::{sym, Symbol};
+use serde::ser::SerializeSeq;
+use serde::{Serialize, Serializer};
+
+use crate::clean::{self, AttributesExt, Deprecation, GetDefId, SelfTy, TypeKind};
+use crate::config::RenderInfo;
+use crate::config::RenderOptions;
+use crate::docfs::{DocFS, PathError};
+use crate::doctree;
+use crate::error::Error;
+use crate::formats::cache::{cache, Cache};
+use crate::formats::item_type::ItemType;
+use crate::formats::{AssocItemRender, FormatRenderer, Impl, RenderMode};
+use crate::html::escape::Escape;
+use crate::html::format::fmt_impl_for_trait_page;
+use crate::html::format::Function;
+use crate::html::format::{href, print_default_space, print_generic_bounds, WhereClause};
+use crate::html::format::{print_abi_with_space, Buffer, PrintWithSpace};
+use crate::html::markdown::{self, ErrorCodes, IdMap, Markdown, MarkdownHtml, MarkdownSummaryLine};
+use crate::html::sources;
+use crate::html::{highlight, layout, static_files};
+use cache::{build_index, ExternalLocation};
+
+/// A pair of name and its optional document.
+pub type NameDoc = (String, Option<String>);
+
+crate fn ensure_trailing_slash(v: &str) -> impl fmt::Display + '_ {
+    crate::html::format::display_fn(move |f| {
+        if !v.ends_with('/') && !v.is_empty() { write!(f, "{}/", v) } else { write!(f, "{}", v) }
+    })
+}
+
+/// Major driving force in all rustdoc rendering. This contains information
+/// about where in the tree-like hierarchy rendering is occurring and controls
+/// how the current page is being rendered.
+///
+/// It is intended that this context is a lightweight object which can be fairly
+/// easily cloned because it is cloned per work-job (about once per item in the
+/// rustdoc tree).
+#[derive(Clone)]
+crate struct Context {
+    /// Current hierarchy of components leading down to what's currently being
+    /// rendered
+    pub current: Vec<String>,
+    /// The current destination folder of where HTML artifacts should be placed.
+    /// This changes as the context descends into the module hierarchy.
+    pub dst: PathBuf,
+    /// A flag, which when `true`, will render pages which redirect to the
+    /// real location of an item. This is used to allow external links to
+    /// publicly reused items to redirect to the right location.
+    pub render_redirect_pages: bool,
+    /// The map used to ensure all generated 'id=' attributes are unique.
+    id_map: Rc<RefCell<IdMap>>,
+    pub shared: Arc<SharedContext>,
+    all: Rc<RefCell<AllTypes>>,
+    /// Storage for the errors produced while generating documentation so they
+    /// can be printed together at the end.
+    pub errors: Rc<Receiver<String>>,
+}
+
+crate struct SharedContext {
+    /// The path to the crate root source minus the file name.
+    /// Used for simplifying paths to the highlighted source code files.
+    pub src_root: PathBuf,
+    /// This describes the layout of each page, and is not modified after
+    /// creation of the context (contains info like the favicon and added html).
+    pub layout: layout::Layout,
+    /// This flag indicates whether `[src]` links should be generated or not. If
+    /// the source files are present in the html rendering, then this will be
+    /// `true`.
+    pub include_sources: bool,
+    /// The local file sources we've emitted and their respective url-paths.
+    pub local_sources: FxHashMap<PathBuf, String>,
+    /// Whether the collapsed pass ran
+    pub collapsed: bool,
+    /// The base-URL of the issue tracker for when an item has been tagged with
+    /// an issue number.
+    pub issue_tracker_base_url: Option<String>,
+    /// The directories that have already been created in this doc run. Used to reduce the number
+    /// of spurious `create_dir_all` calls.
+    pub created_dirs: RefCell<FxHashSet<PathBuf>>,
+    /// This flag indicates whether listings of modules (in the side bar and documentation itself)
+    /// should be ordered alphabetically or in order of appearance (in the source code).
+    pub sort_modules_alphabetically: bool,
+    /// Additional CSS files to be added to the generated docs.
+    pub style_files: Vec<StylePath>,
+    /// Suffix to be added on resource files (if suffix is "-v2" then "light.css" becomes
+    /// "light-v2.css").
+    pub resource_suffix: String,
+    /// Optional path string to be used to load static files on output pages. If not set, uses
+    /// combinations of `../` to reach the documentation root.
+    pub static_root_path: Option<String>,
+    /// The fs handle we are working with.
+    pub fs: DocFS,
+    /// The default edition used to parse doctests.
+    pub edition: Edition,
+    pub codes: ErrorCodes,
+    playground: Option<markdown::Playground>,
+}
+
+impl Context {
+    fn path(&self, filename: &str) -> PathBuf {
+        // We use splitn vs Path::extension here because we might get a filename
+        // like `style.min.css` and we want to process that into
+        // `style-suffix.min.css`.  Path::extension would just return `css`
+        // which would result in `style.min-suffix.css` which isn't what we
+        // want.
+        let mut iter = filename.splitn(2, '.');
+        let base = iter.next().unwrap();
+        let ext = iter.next().unwrap();
+        let filename = format!("{}{}.{}", base, self.shared.resource_suffix, ext,);
+        self.dst.join(&filename)
+    }
+}
+
+impl SharedContext {
+    crate fn ensure_dir(&self, dst: &Path) -> Result<(), Error> {
+        let mut dirs = self.created_dirs.borrow_mut();
+        if !dirs.contains(dst) {
+            try_err!(self.fs.create_dir_all(dst), dst);
+            dirs.insert(dst.to_path_buf());
+        }
+
+        Ok(())
+    }
+
+    /// Based on whether the `collapse-docs` pass was run, return either the `doc_value` or the
+    /// `collapsed_doc_value` of the given item.
+    pub fn maybe_collapsed_doc_value<'a>(&self, item: &'a clean::Item) -> Option<Cow<'a, str>> {
+        if self.collapsed {
+            item.collapsed_doc_value().map(|s| s.into())
+        } else {
+            item.doc_value().map(|s| s.into())
+        }
+    }
+}
+
+// Helper structs for rendering items/sidebars and carrying along contextual
+// information
+
+/// Struct representing one entry in the JS search index. These are all emitted
+/// by hand to a large JS file at the end of cache-creation.
+#[derive(Debug)]
+pub struct IndexItem {
+    pub ty: ItemType,
+    pub name: String,
+    pub path: String,
+    pub desc: String,
+    pub parent: Option<DefId>,
+    pub parent_idx: Option<usize>,
+    pub search_type: Option<IndexItemFunctionType>,
+}
+
+impl Serialize for IndexItem {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        assert_eq!(
+            self.parent.is_some(),
+            self.parent_idx.is_some(),
+            "`{}` is missing idx",
+            self.name
+        );
+
+        (self.ty, &self.name, &self.path, &self.desc, self.parent_idx, &self.search_type)
+            .serialize(serializer)
+    }
+}
+
+/// A type used for the search index.
+#[derive(Debug)]
+crate struct RenderType {
+    ty: Option<DefId>,
+    idx: Option<usize>,
+    name: Option<String>,
+    generics: Option<Vec<Generic>>,
+}
+
+impl Serialize for RenderType {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        if let Some(name) = &self.name {
+            let mut seq = serializer.serialize_seq(None)?;
+            if let Some(id) = self.idx {
+                seq.serialize_element(&id)?;
+            } else {
+                seq.serialize_element(&name)?;
+            }
+            if let Some(generics) = &self.generics {
+                seq.serialize_element(&generics)?;
+            }
+            seq.end()
+        } else {
+            serializer.serialize_none()
+        }
+    }
+}
+
+/// A type used for the search index.
+#[derive(Debug)]
+crate struct Generic {
+    name: String,
+    defid: Option<DefId>,
+    idx: Option<usize>,
+}
+
+impl Serialize for Generic {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        if let Some(id) = self.idx {
+            serializer.serialize_some(&id)
+        } else {
+            serializer.serialize_some(&self.name)
+        }
+    }
+}
+
+/// Full type of functions/methods in the search index.
+#[derive(Debug)]
+pub struct IndexItemFunctionType {
+    inputs: Vec<TypeWithKind>,
+    output: Option<Vec<TypeWithKind>>,
+}
+
+impl Serialize for IndexItemFunctionType {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        // If we couldn't figure out a type, just write `null`.
+        let mut iter = self.inputs.iter();
+        if match self.output {
+            Some(ref output) => iter.chain(output.iter()).any(|ref i| i.ty.name.is_none()),
+            None => iter.any(|ref i| i.ty.name.is_none()),
+        } {
+            serializer.serialize_none()
+        } else {
+            let mut seq = serializer.serialize_seq(None)?;
+            seq.serialize_element(&self.inputs)?;
+            if let Some(output) = &self.output {
+                if output.len() > 1 {
+                    seq.serialize_element(&output)?;
+                } else {
+                    seq.serialize_element(&output[0])?;
+                }
+            }
+            seq.end()
+        }
+    }
+}
+
+#[derive(Debug)]
+crate struct TypeWithKind {
+    ty: RenderType,
+    kind: TypeKind,
+}
+
+impl From<(RenderType, TypeKind)> for TypeWithKind {
+    fn from(x: (RenderType, TypeKind)) -> TypeWithKind {
+        TypeWithKind { ty: x.0, kind: x.1 }
+    }
+}
+
+impl Serialize for TypeWithKind {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        let mut seq = serializer.serialize_seq(None)?;
+        seq.serialize_element(&self.ty.name)?;
+        let x: ItemType = self.kind.into();
+        seq.serialize_element(&x)?;
+        seq.end()
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct StylePath {
+    /// The path to the theme
+    pub path: PathBuf,
+    /// What the `disabled` attribute should be set to in the HTML tag
+    pub disabled: bool,
+}
+
+thread_local!(pub static CURRENT_DEPTH: Cell<usize> = Cell::new(0));
+
+pub fn initial_ids() -> Vec<String> {
+    [
+        "main",
+        "search",
+        "help",
+        "TOC",
+        "render-detail",
+        "associated-types",
+        "associated-const",
+        "required-methods",
+        "provided-methods",
+        "implementors",
+        "synthetic-implementors",
+        "implementors-list",
+        "synthetic-implementors-list",
+        "methods",
+        "deref-methods",
+        "implementations",
+    ]
+    .iter()
+    .map(|id| (String::from(*id)))
+    .collect()
+}
+
+/// Generates the documentation for `crate` into the directory `dst`
+impl FormatRenderer for Context {
+    fn init(
+        mut krate: clean::Crate,
+        options: RenderOptions,
+        _render_info: RenderInfo,
+        edition: Edition,
+        cache: &mut Cache,
+    ) -> Result<(Context, clean::Crate), Error> {
+        // need to save a copy of the options for rendering the index page
+        let md_opts = options.clone();
+        let RenderOptions {
+            output,
+            external_html,
+            id_map,
+            playground_url,
+            sort_modules_alphabetically,
+            themes: style_files,
+            extension_css,
+            resource_suffix,
+            static_root_path,
+            generate_search_filter,
+            ..
+        } = options;
+
+        let src_root = match krate.src {
+            FileName::Real(ref p) => match p.local_path().parent() {
+                Some(p) => p.to_path_buf(),
+                None => PathBuf::new(),
+            },
+            _ => PathBuf::new(),
+        };
+        // If user passed in `--playground-url` arg, we fill in crate name here
+        let mut playground = None;
+        if let Some(url) = playground_url {
+            playground = Some(markdown::Playground { crate_name: Some(krate.name.clone()), url });
+        }
+        let mut layout = layout::Layout {
+            logo: String::new(),
+            favicon: String::new(),
+            external_html,
+            krate: krate.name.clone(),
+            css_file_extension: extension_css,
+            generate_search_filter,
+        };
+        let mut issue_tracker_base_url = None;
+        let mut include_sources = true;
+
+        // Crawl the crate attributes looking for attributes which control how we're
+        // going to emit HTML
+        if let Some(attrs) = krate.module.as_ref().map(|m| &m.attrs) {
+            for attr in attrs.lists(sym::doc) {
+                match (attr.name_or_empty(), attr.value_str()) {
+                    (sym::html_favicon_url, Some(s)) => {
+                        layout.favicon = s.to_string();
+                    }
+                    (sym::html_logo_url, Some(s)) => {
+                        layout.logo = s.to_string();
+                    }
+                    (sym::html_playground_url, Some(s)) => {
+                        playground = Some(markdown::Playground {
+                            crate_name: Some(krate.name.clone()),
+                            url: s.to_string(),
+                        });
+                    }
+                    (sym::issue_tracker_base_url, Some(s)) => {
+                        issue_tracker_base_url = Some(s.to_string());
+                    }
+                    (sym::html_no_source, None) if attr.is_word() => {
+                        include_sources = false;
+                    }
+                    _ => {}
+                }
+            }
+        }
+        let (sender, receiver) = channel();
+        let mut scx = SharedContext {
+            collapsed: krate.collapsed,
+            src_root,
+            include_sources,
+            local_sources: Default::default(),
+            issue_tracker_base_url,
+            layout,
+            created_dirs: Default::default(),
+            sort_modules_alphabetically,
+            style_files,
+            resource_suffix,
+            static_root_path,
+            fs: DocFS::new(sender),
+            edition,
+            codes: ErrorCodes::from(UnstableFeatures::from_environment().is_nightly_build()),
+            playground,
+        };
+
+        // Add the default themes to the `Vec` of stylepaths
+        //
+        // Note that these must be added before `sources::render` is called
+        // so that the resulting source pages are styled
+        //
+        // `light.css` is not disabled because it is the stylesheet that stays loaded
+        // by the browser as the theme stylesheet. The theme system (hackily) works by
+        // changing the href to this stylesheet. All other themes are disabled to
+        // prevent rule conflicts
+        scx.style_files.push(StylePath { path: PathBuf::from("light.css"), disabled: false });
+        scx.style_files.push(StylePath { path: PathBuf::from("dark.css"), disabled: true });
+        scx.style_files.push(StylePath { path: PathBuf::from("ayu.css"), disabled: true });
+
+        let dst = output;
+        scx.ensure_dir(&dst)?;
+        krate = sources::render(&dst, &mut scx, krate)?;
+
+        // Build our search index
+        let index = build_index(&krate, cache);
+
+        let cache = Arc::new(cache);
+        let mut cx = Context {
+            current: Vec::new(),
+            dst,
+            render_redirect_pages: false,
+            id_map: Rc::new(RefCell::new(id_map)),
+            shared: Arc::new(scx),
+            all: Rc::new(RefCell::new(AllTypes::new())),
+            errors: Rc::new(receiver),
+        };
+
+        CURRENT_DEPTH.with(|s| s.set(0));
+
+        // Write shared runs within a flock; disable thread dispatching of IO temporarily.
+        Arc::get_mut(&mut cx.shared).unwrap().fs.set_sync_only(true);
+        write_shared(&cx, &krate, index, &md_opts, &cache)?;
+        Arc::get_mut(&mut cx.shared).unwrap().fs.set_sync_only(false);
+        Ok((cx, krate))
+    }
+
+    fn after_run(&mut self, diag: &rustc_errors::Handler) -> Result<(), Error> {
+        Arc::get_mut(&mut self.shared).unwrap().fs.close();
+        let nb_errors = self.errors.iter().map(|err| diag.struct_err(&err).emit()).count();
+        if nb_errors > 0 {
+            Err(Error::new(io::Error::new(io::ErrorKind::Other, "I/O error"), ""))
+        } else {
+            Ok(())
+        }
+    }
+
+    fn after_krate(&mut self, krate: &clean::Crate, cache: &Cache) -> Result<(), Error> {
+        let final_file = self.dst.join(&krate.name).join("all.html");
+        let settings_file = self.dst.join("settings.html");
+        let crate_name = krate.name.clone();
+
+        let mut root_path = self.dst.to_str().expect("invalid path").to_owned();
+        if !root_path.ends_with('/') {
+            root_path.push('/');
+        }
+        let mut page = layout::Page {
+            title: "List of all items in this crate",
+            css_class: "mod",
+            root_path: "../",
+            static_root_path: self.shared.static_root_path.as_deref(),
+            description: "List of all items in this crate",
+            keywords: BASIC_KEYWORDS,
+            resource_suffix: &self.shared.resource_suffix,
+            extra_scripts: &[],
+            static_extra_scripts: &[],
+        };
+        let sidebar = if let Some(ref version) = cache.crate_version {
+            format!(
+                "<p class='location'>Crate {}</p>\
+                     <div class='block version'>\
+                         <p>Version {}</p>\
+                     </div>\
+                     <a id='all-types' href='index.html'><p>Back to index</p></a>",
+                crate_name,
+                Escape(version),
+            )
+        } else {
+            String::new()
+        };
+        let all = self.all.replace(AllTypes::new());
+        let v = layout::render(
+            &self.shared.layout,
+            &page,
+            sidebar,
+            |buf: &mut Buffer| all.print(buf),
+            &self.shared.style_files,
+        );
+        self.shared.fs.write(&final_file, v.as_bytes())?;
+
+        // Generating settings page.
+        page.title = "Rustdoc settings";
+        page.description = "Settings of Rustdoc";
+        page.root_path = "./";
+
+        let mut style_files = self.shared.style_files.clone();
+        let sidebar = "<p class='location'>Settings</p><div class='sidebar-elems'></div>";
+        style_files.push(StylePath { path: PathBuf::from("settings.css"), disabled: false });
+        let v = layout::render(
+            &self.shared.layout,
+            &page,
+            sidebar,
+            settings(
+                self.shared.static_root_path.as_deref().unwrap_or("./"),
+                &self.shared.resource_suffix,
+            ),
+            &style_files,
+        );
+        self.shared.fs.write(&settings_file, v.as_bytes())?;
+        Ok(())
+    }
+
+    fn mod_item_in(
+        &mut self,
+        item: &clean::Item,
+        item_name: &str,
+        cache: &Cache,
+    ) -> Result<(), Error> {
+        // Stripped modules survive the rustdoc passes (i.e., `strip-private`)
+        // if they contain impls for public types. These modules can also
+        // contain items such as publicly re-exported structures.
+        //
+        // External crates will provide links to these structures, so
+        // these modules are recursed into, but not rendered normally
+        // (a flag on the context).
+        if !self.render_redirect_pages {
+            self.render_redirect_pages = item.is_stripped();
+        }
+        let scx = &self.shared;
+        self.dst.push(item_name);
+        self.current.push(item_name.to_owned());
+
+        info!("Recursing into {}", self.dst.display());
+
+        let buf = self.render_item(item, false, cache);
+        // buf will be empty if the module is stripped and there is no redirect for it
+        if !buf.is_empty() {
+            self.shared.ensure_dir(&self.dst)?;
+            let joint_dst = self.dst.join("index.html");
+            scx.fs.write(&joint_dst, buf.as_bytes())?;
+        }
+
+        // Render sidebar-items.js used throughout this module.
+        if !self.render_redirect_pages {
+            let module = match item.inner {
+                clean::StrippedItem(box clean::ModuleItem(ref m)) | clean::ModuleItem(ref m) => m,
+                _ => unreachable!(),
+            };
+            let items = self.build_sidebar_items(module);
+            let js_dst = self.dst.join("sidebar-items.js");
+            let v = format!("initSidebarItems({});", serde_json::to_string(&items).unwrap());
+            scx.fs.write(&js_dst, &v)?;
+        }
+        Ok(())
+    }
+
+    fn mod_item_out(&mut self, _item_name: &str) -> Result<(), Error> {
+        info!("Recursed; leaving {}", self.dst.display());
+
+        // Go back to where we were at
+        self.dst.pop();
+        self.current.pop();
+        Ok(())
+    }
+
+    fn item(&mut self, item: clean::Item, cache: &Cache) -> Result<(), Error> {
+        // Stripped modules survive the rustdoc passes (i.e., `strip-private`)
+        // if they contain impls for public types. These modules can also
+        // contain items such as publicly re-exported structures.
+        //
+        // External crates will provide links to these structures, so
+        // these modules are recursed into, but not rendered normally
+        // (a flag on the context).
+        if !self.render_redirect_pages {
+            self.render_redirect_pages = item.is_stripped();
+        }
+
+        let buf = self.render_item(&item, true, cache);
+        // buf will be empty if the item is stripped and there is no redirect for it
+        if !buf.is_empty() {
+            let name = item.name.as_ref().unwrap();
+            let item_type = item.type_();
+            let file_name = &item_path(item_type, name);
+            self.shared.ensure_dir(&self.dst)?;
+            let joint_dst = self.dst.join(file_name);
+            self.shared.fs.write(&joint_dst, buf.as_bytes())?;
+
+            if !self.render_redirect_pages {
+                self.all.borrow_mut().append(full_path(self, &item), &item_type);
+            }
+            // If the item is a macro, redirect from the old macro URL (with !)
+            // to the new one (without).
+            if item_type == ItemType::Macro {
+                let redir_name = format!("{}.{}!.html", item_type, name);
+                let redir_dst = self.dst.join(redir_name);
+                let v = layout::redirect(file_name);
+                self.shared.fs.write(&redir_dst, v.as_bytes())?;
+            }
+        }
+        Ok(())
+    }
+}
+
+fn write_shared(
+    cx: &Context,
+    krate: &clean::Crate,
+    search_index: String,
+    options: &RenderOptions,
+    cache: &Cache,
+) -> Result<(), Error> {
+    // Write out the shared files. Note that these are shared among all rustdoc
+    // docs placed in the output directory, so this needs to be a synchronized
+    // operation with respect to all other rustdocs running around.
+    let lock_file = cx.dst.join(".lock");
+    let _lock = try_err!(flock::Lock::new(&lock_file, true, true, true), &lock_file);
+
+    // Add all the static files. These may already exist, but we just
+    // overwrite them anyway to make sure that they're fresh and up-to-date.
+
+    write_minify(
+        &cx.shared.fs,
+        cx.path("rustdoc.css"),
+        static_files::RUSTDOC_CSS,
+        options.enable_minification,
+    )?;
+    write_minify(
+        &cx.shared.fs,
+        cx.path("settings.css"),
+        static_files::SETTINGS_CSS,
+        options.enable_minification,
+    )?;
+    write_minify(
+        &cx.shared.fs,
+        cx.path("noscript.css"),
+        static_files::NOSCRIPT_CSS,
+        options.enable_minification,
+    )?;
+
+    // To avoid "light.css" to be overwritten, we'll first run over the received themes and only
+    // then we'll run over the "official" styles.
+    let mut themes: FxHashSet<String> = FxHashSet::default();
+
+    for entry in &cx.shared.style_files {
+        let theme = try_none!(try_none!(entry.path.file_stem(), &entry.path).to_str(), &entry.path);
+        let extension =
+            try_none!(try_none!(entry.path.extension(), &entry.path).to_str(), &entry.path);
+
+        // Handle the official themes
+        match theme {
+            "light" => write_minify(
+                &cx.shared.fs,
+                cx.path("light.css"),
+                static_files::themes::LIGHT,
+                options.enable_minification,
+            )?,
+            "dark" => write_minify(
+                &cx.shared.fs,
+                cx.path("dark.css"),
+                static_files::themes::DARK,
+                options.enable_minification,
+            )?,
+            "ayu" => write_minify(
+                &cx.shared.fs,
+                cx.path("ayu.css"),
+                static_files::themes::AYU,
+                options.enable_minification,
+            )?,
+            _ => {
+                // Handle added third-party themes
+                let content = try_err!(fs::read(&entry.path), &entry.path);
+                cx.shared
+                    .fs
+                    .write(cx.path(&format!("{}.{}", theme, extension)), content.as_slice())?;
+            }
+        };
+
+        themes.insert(theme.to_owned());
+    }
+
+    let write = |p, c| cx.shared.fs.write(p, c);
+    if (*cx.shared).layout.logo.is_empty() {
+        write(cx.path("rust-logo.png"), static_files::RUST_LOGO)?;
+    }
+    if (*cx.shared).layout.favicon.is_empty() {
+        write(cx.path("favicon.ico"), static_files::RUST_FAVICON)?;
+    }
+    write(cx.path("brush.svg"), static_files::BRUSH_SVG)?;
+    write(cx.path("wheel.svg"), static_files::WHEEL_SVG)?;
+    write(cx.path("down-arrow.svg"), static_files::DOWN_ARROW_SVG)?;
+
+    let mut themes: Vec<&String> = themes.iter().collect();
+    themes.sort();
+    // To avoid theme switch latencies as much as possible, we put everything theme related
+    // at the beginning of the html files into another js file.
+    let theme_js = format!(
+        r#"var themes = document.getElementById("theme-choices");
+var themePicker = document.getElementById("theme-picker");
+
+function showThemeButtonState() {{
+    themes.style.display = "block";
+    themePicker.style.borderBottomRightRadius = "0";
+    themePicker.style.borderBottomLeftRadius = "0";
+}}
+
+function hideThemeButtonState() {{
+    themes.style.display = "none";
+    themePicker.style.borderBottomRightRadius = "3px";
+    themePicker.style.borderBottomLeftRadius = "3px";
+}}
+
+function switchThemeButtonState() {{
+    if (themes.style.display === "block") {{
+        hideThemeButtonState();
+    }} else {{
+        showThemeButtonState();
+    }}
+}};
+
+function handleThemeButtonsBlur(e) {{
+    var active = document.activeElement;
+    var related = e.relatedTarget;
+
+    if (active.id !== "themePicker" &&
+        (!active.parentNode || active.parentNode.id !== "theme-choices") &&
+        (!related ||
+         (related.id !== "themePicker" &&
+          (!related.parentNode || related.parentNode.id !== "theme-choices")))) {{
+        hideThemeButtonState();
+    }}
+}}
+
+themePicker.onclick = switchThemeButtonState;
+themePicker.onblur = handleThemeButtonsBlur;
+{}.forEach(function(item) {{
+    var but = document.createElement('button');
+    but.textContent = item;
+    but.onclick = function(el) {{
+        switchTheme(currentTheme, mainTheme, item, true);
+    }};
+    but.onblur = handleThemeButtonsBlur;
+    themes.appendChild(but);
+}});"#,
+        serde_json::to_string(&themes).unwrap()
+    );
+
+    write_minify(&cx.shared.fs, cx.path("theme.js"), &theme_js, options.enable_minification)?;
+    write_minify(
+        &cx.shared.fs,
+        cx.path("main.js"),
+        static_files::MAIN_JS,
+        options.enable_minification,
+    )?;
+    write_minify(
+        &cx.shared.fs,
+        cx.path("settings.js"),
+        static_files::SETTINGS_JS,
+        options.enable_minification,
+    )?;
+    if cx.shared.include_sources {
+        write_minify(
+            &cx.shared.fs,
+            cx.path("source-script.js"),
+            static_files::sidebar::SOURCE_SCRIPT,
+            options.enable_minification,
+        )?;
+    }
+
+    {
+        write_minify(
+            &cx.shared.fs,
+            cx.path("storage.js"),
+            &format!(
+                "var resourcesSuffix = \"{}\";{}",
+                cx.shared.resource_suffix,
+                static_files::STORAGE_JS
+            ),
+            options.enable_minification,
+        )?;
+    }
+
+    if let Some(ref css) = cx.shared.layout.css_file_extension {
+        let out = cx.path("theme.css");
+        let buffer = try_err!(fs::read_to_string(css), css);
+        if !options.enable_minification {
+            cx.shared.fs.write(&out, &buffer)?;
+        } else {
+            write_minify(&cx.shared.fs, out, &buffer, options.enable_minification)?;
+        }
+    }
+    write_minify(
+        &cx.shared.fs,
+        cx.path("normalize.css"),
+        static_files::NORMALIZE_CSS,
+        options.enable_minification,
+    )?;
+    write(cx.dst.join("FiraSans-Regular.woff"), static_files::fira_sans::REGULAR)?;
+    write(cx.dst.join("FiraSans-Medium.woff"), static_files::fira_sans::MEDIUM)?;
+    write(cx.dst.join("FiraSans-LICENSE.txt"), static_files::fira_sans::LICENSE)?;
+    write(cx.dst.join("SourceSerifPro-Regular.ttf.woff"), static_files::source_serif_pro::REGULAR)?;
+    write(cx.dst.join("SourceSerifPro-Bold.ttf.woff"), static_files::source_serif_pro::BOLD)?;
+    write(cx.dst.join("SourceSerifPro-It.ttf.woff"), static_files::source_serif_pro::ITALIC)?;
+    write(cx.dst.join("SourceSerifPro-LICENSE.md"), static_files::source_serif_pro::LICENSE)?;
+    write(cx.dst.join("SourceCodePro-Regular.woff"), static_files::source_code_pro::REGULAR)?;
+    write(cx.dst.join("SourceCodePro-Semibold.woff"), static_files::source_code_pro::SEMIBOLD)?;
+    write(cx.dst.join("SourceCodePro-LICENSE.txt"), static_files::source_code_pro::LICENSE)?;
+    write(cx.dst.join("LICENSE-MIT.txt"), static_files::LICENSE_MIT)?;
+    write(cx.dst.join("LICENSE-APACHE.txt"), static_files::LICENSE_APACHE)?;
+    write(cx.dst.join("COPYRIGHT.txt"), static_files::COPYRIGHT)?;
+
+    fn collect(path: &Path, krate: &str, key: &str) -> io::Result<(Vec<String>, Vec<String>)> {
+        let mut ret = Vec::new();
+        let mut krates = Vec::new();
+
+        if path.exists() {
+            for line in BufReader::new(File::open(path)?).lines() {
+                let line = line?;
+                if !line.starts_with(key) {
+                    continue;
+                }
+                if line.starts_with(&format!(r#"{}["{}"]"#, key, krate)) {
+                    continue;
+                }
+                ret.push(line.to_string());
+                krates.push(
+                    line[key.len() + 2..]
+                        .split('"')
+                        .next()
+                        .map(|s| s.to_owned())
+                        .unwrap_or_else(String::new),
+                );
+            }
+        }
+        Ok((ret, krates))
+    }
+
+    fn collect_json(path: &Path, krate: &str) -> io::Result<(Vec<String>, Vec<String>)> {
+        let mut ret = Vec::new();
+        let mut krates = Vec::new();
+
+        if path.exists() {
+            for line in BufReader::new(File::open(path)?).lines() {
+                let line = line?;
+                if !line.starts_with('"') {
+                    continue;
+                }
+                if line.starts_with(&format!("\"{}\"", krate)) {
+                    continue;
+                }
+                if line.ends_with(",\\") {
+                    ret.push(line[..line.len() - 2].to_string());
+                } else {
+                    // Ends with "\\" (it's the case for the last added crate line)
+                    ret.push(line[..line.len() - 1].to_string());
+                }
+                krates.push(
+                    line.split('"')
+                        .find(|s| !s.is_empty())
+                        .map(|s| s.to_owned())
+                        .unwrap_or_else(String::new),
+                );
+            }
+        }
+        Ok((ret, krates))
+    }
+
+    use std::ffi::OsString;
+
+    #[derive(Debug)]
+    struct Hierarchy {
+        elem: OsString,
+        children: FxHashMap<OsString, Hierarchy>,
+        elems: FxHashSet<OsString>,
+    }
+
+    impl Hierarchy {
+        fn new(elem: OsString) -> Hierarchy {
+            Hierarchy { elem, children: FxHashMap::default(), elems: FxHashSet::default() }
+        }
+
+        fn to_json_string(&self) -> String {
+            let mut subs: Vec<&Hierarchy> = self.children.values().collect();
+            subs.sort_unstable_by(|a, b| a.elem.cmp(&b.elem));
+            let mut files = self
+                .elems
+                .iter()
+                .map(|s| format!("\"{}\"", s.to_str().expect("invalid osstring conversion")))
+                .collect::<Vec<_>>();
+            files.sort_unstable_by(|a, b| a.cmp(b));
+            let subs = subs.iter().map(|s| s.to_json_string()).collect::<Vec<_>>().join(",");
+            let dirs =
+                if subs.is_empty() { String::new() } else { format!(",\"dirs\":[{}]", subs) };
+            let files = files.join(",");
+            let files =
+                if files.is_empty() { String::new() } else { format!(",\"files\":[{}]", files) };
+            format!(
+                "{{\"name\":\"{name}\"{dirs}{files}}}",
+                name = self.elem.to_str().expect("invalid osstring conversion"),
+                dirs = dirs,
+                files = files
+            )
+        }
+    }
+
+    if cx.shared.include_sources {
+        let mut hierarchy = Hierarchy::new(OsString::new());
+        for source in cx
+            .shared
+            .local_sources
+            .iter()
+            .filter_map(|p| p.0.strip_prefix(&cx.shared.src_root).ok())
+        {
+            let mut h = &mut hierarchy;
+            let mut elems = source
+                .components()
+                .filter_map(|s| match s {
+                    Component::Normal(s) => Some(s.to_owned()),
+                    _ => None,
+                })
+                .peekable();
+            loop {
+                let cur_elem = elems.next().expect("empty file path");
+                if elems.peek().is_none() {
+                    h.elems.insert(cur_elem);
+                    break;
+                } else {
+                    let e = cur_elem.clone();
+                    h.children.entry(cur_elem.clone()).or_insert_with(|| Hierarchy::new(e));
+                    h = h.children.get_mut(&cur_elem).expect("not found child");
+                }
+            }
+        }
+
+        let dst = cx.dst.join(&format!("source-files{}.js", cx.shared.resource_suffix));
+        let (mut all_sources, _krates) = try_err!(collect(&dst, &krate.name, "sourcesIndex"), &dst);
+        all_sources.push(format!(
+            "sourcesIndex[\"{}\"] = {};",
+            &krate.name,
+            hierarchy.to_json_string()
+        ));
+        all_sources.sort();
+        let v = format!(
+            "var N = null;var sourcesIndex = {{}};\n{}\ncreateSourceSidebar();\n",
+            all_sources.join("\n")
+        );
+        cx.shared.fs.write(&dst, v.as_bytes())?;
+    }
+
+    // Update the search index
+    let dst = cx.dst.join(&format!("search-index{}.js", cx.shared.resource_suffix));
+    let (mut all_indexes, mut krates) = try_err!(collect_json(&dst, &krate.name), &dst);
+    all_indexes.push(search_index);
+
+    // Sort the indexes by crate so the file will be generated identically even
+    // with rustdoc running in parallel.
+    all_indexes.sort();
+    {
+        let mut v = String::from("var searchIndex = JSON.parse('{\\\n");
+        v.push_str(&all_indexes.join(",\\\n"));
+        // "addSearchOptions" has to be called first so the crate filtering can be set before the
+        // search might start (if it's set into the URL for example).
+        v.push_str("\\\n}');\naddSearchOptions(searchIndex);initSearch(searchIndex);");
+        cx.shared.fs.write(&dst, &v)?;
+    }
+    if options.enable_index_page {
+        if let Some(index_page) = options.index_page.clone() {
+            let mut md_opts = options.clone();
+            md_opts.output = cx.dst.clone();
+            md_opts.external_html = (*cx.shared).layout.external_html.clone();
+
+            crate::markdown::render(&index_page, md_opts, cx.shared.edition)
+                .map_err(|e| Error::new(e, &index_page))?;
+        } else {
+            let dst = cx.dst.join("index.html");
+            let page = layout::Page {
+                title: "Index of crates",
+                css_class: "mod",
+                root_path: "./",
+                static_root_path: cx.shared.static_root_path.as_deref(),
+                description: "List of crates",
+                keywords: BASIC_KEYWORDS,
+                resource_suffix: &cx.shared.resource_suffix,
+                extra_scripts: &[],
+                static_extra_scripts: &[],
+            };
+            krates.push(krate.name.clone());
+            krates.sort();
+            krates.dedup();
+
+            let content = format!(
+                "<h1 class='fqn'>\
+     <span class='in-band'>List of all crates</span>\
+</h1><ul class='mod'>{}</ul>",
+                krates
+                    .iter()
+                    .map(|s| {
+                        format!("<li><a href=\"{}index.html\">{}</li>", ensure_trailing_slash(s), s)
+                    })
+                    .collect::<String>()
+            );
+            let v = layout::render(&cx.shared.layout, &page, "", content, &cx.shared.style_files);
+            cx.shared.fs.write(&dst, v.as_bytes())?;
+        }
+    }
+
+    // Update the list of all implementors for traits
+    let dst = cx.dst.join("implementors");
+    for (&did, imps) in &cache.implementors {
+        // Private modules can leak through to this phase of rustdoc, which
+        // could contain implementations for otherwise private types. In some
+        // rare cases we could find an implementation for an item which wasn't
+        // indexed, so we just skip this step in that case.
+        //
+        // FIXME: this is a vague explanation for why this can't be a `get`, in
+        //        theory it should be...
+        let &(ref remote_path, remote_item_type) = match cache.paths.get(&did) {
+            Some(p) => p,
+            None => match cache.external_paths.get(&did) {
+                Some(p) => p,
+                None => continue,
+            },
+        };
+
+        #[derive(Serialize)]
+        struct Implementor {
+            text: String,
+            synthetic: bool,
+            types: Vec<String>,
+        }
+
+        let implementors = imps
+            .iter()
+            .filter_map(|imp| {
+                // If the trait and implementation are in the same crate, then
+                // there's no need to emit information about it (there's inlining
+                // going on). If they're in different crates then the crate defining
+                // the trait will be interested in our implementation.
+                //
+                // If the implementation is from another crate then that crate
+                // should add it.
+                if imp.impl_item.def_id.krate == did.krate || !imp.impl_item.def_id.is_local() {
+                    None
+                } else {
+                    Some(Implementor {
+                        text: imp.inner_impl().print().to_string(),
+                        synthetic: imp.inner_impl().synthetic,
+                        types: collect_paths_for_type(imp.inner_impl().for_.clone()),
+                    })
+                }
+            })
+            .collect::<Vec<_>>();
+
+        // Only create a js file if we have impls to add to it. If the trait is
+        // documented locally though we always create the file to avoid dead
+        // links.
+        if implementors.is_empty() && !cache.paths.contains_key(&did) {
+            continue;
+        }
+
+        let implementors = format!(
+            r#"implementors["{}"] = {};"#,
+            krate.name,
+            serde_json::to_string(&implementors).unwrap()
+        );
+
+        let mut mydst = dst.clone();
+        for part in &remote_path[..remote_path.len() - 1] {
+            mydst.push(part);
+        }
+        cx.shared.ensure_dir(&mydst)?;
+        mydst.push(&format!("{}.{}.js", remote_item_type, remote_path[remote_path.len() - 1]));
+
+        let (mut all_implementors, _) =
+            try_err!(collect(&mydst, &krate.name, "implementors"), &mydst);
+        all_implementors.push(implementors);
+        // Sort the implementors by crate so the file will be generated
+        // identically even with rustdoc running in parallel.
+        all_implementors.sort();
+
+        let mut v = String::from("(function() {var implementors = {};\n");
+        for implementor in &all_implementors {
+            writeln!(v, "{}", *implementor).unwrap();
+        }
+        v.push_str(
+            "if (window.register_implementors) {\
+                 window.register_implementors(implementors);\
+             } else {\
+                 window.pending_implementors = implementors;\
+             }",
+        );
+        v.push_str("})()");
+        cx.shared.fs.write(&mydst, &v)?;
+    }
+    Ok(())
+}
+
+fn write_minify(
+    fs: &DocFS,
+    dst: PathBuf,
+    contents: &str,
+    enable_minification: bool,
+) -> Result<(), Error> {
+    if enable_minification {
+        if dst.extension() == Some(&OsStr::new("css")) {
+            let res = try_none!(minifier::css::minify(contents).ok(), &dst);
+            fs.write(dst, res.as_bytes())
+        } else {
+            fs.write(dst, minifier::js::minify(contents).as_bytes())
+        }
+    } else {
+        fs.write(dst, contents.as_bytes())
+    }
+}
+
+#[derive(Debug, Eq, PartialEq, Hash)]
+struct ItemEntry {
+    url: String,
+    name: String,
+}
+
+impl ItemEntry {
+    fn new(mut url: String, name: String) -> ItemEntry {
+        while url.starts_with('/') {
+            url.remove(0);
+        }
+        ItemEntry { url, name }
+    }
+}
+
+impl ItemEntry {
+    crate fn print(&self) -> impl fmt::Display + '_ {
+        crate::html::format::display_fn(move |f| {
+            write!(f, "<a href='{}'>{}</a>", self.url, Escape(&self.name))
+        })
+    }
+}
+
+impl PartialOrd for ItemEntry {
+    fn partial_cmp(&self, other: &ItemEntry) -> Option<::std::cmp::Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl Ord for ItemEntry {
+    fn cmp(&self, other: &ItemEntry) -> ::std::cmp::Ordering {
+        self.name.cmp(&other.name)
+    }
+}
+
+#[derive(Debug)]
+struct AllTypes {
+    structs: FxHashSet<ItemEntry>,
+    enums: FxHashSet<ItemEntry>,
+    unions: FxHashSet<ItemEntry>,
+    primitives: FxHashSet<ItemEntry>,
+    traits: FxHashSet<ItemEntry>,
+    macros: FxHashSet<ItemEntry>,
+    functions: FxHashSet<ItemEntry>,
+    typedefs: FxHashSet<ItemEntry>,
+    opaque_tys: FxHashSet<ItemEntry>,
+    statics: FxHashSet<ItemEntry>,
+    constants: FxHashSet<ItemEntry>,
+    keywords: FxHashSet<ItemEntry>,
+    attributes: FxHashSet<ItemEntry>,
+    derives: FxHashSet<ItemEntry>,
+    trait_aliases: FxHashSet<ItemEntry>,
+}
+
+impl AllTypes {
+    fn new() -> AllTypes {
+        let new_set = |cap| FxHashSet::with_capacity_and_hasher(cap, Default::default());
+        AllTypes {
+            structs: new_set(100),
+            enums: new_set(100),
+            unions: new_set(100),
+            primitives: new_set(26),
+            traits: new_set(100),
+            macros: new_set(100),
+            functions: new_set(100),
+            typedefs: new_set(100),
+            opaque_tys: new_set(100),
+            statics: new_set(100),
+            constants: new_set(100),
+            keywords: new_set(100),
+            attributes: new_set(100),
+            derives: new_set(100),
+            trait_aliases: new_set(100),
+        }
+    }
+
+    fn append(&mut self, item_name: String, item_type: &ItemType) {
+        let mut url: Vec<_> = item_name.split("::").skip(1).collect();
+        if let Some(name) = url.pop() {
+            let new_url = format!("{}/{}.{}.html", url.join("/"), item_type, name);
+            url.push(name);
+            let name = url.join("::");
+            match *item_type {
+                ItemType::Struct => self.structs.insert(ItemEntry::new(new_url, name)),
+                ItemType::Enum => self.enums.insert(ItemEntry::new(new_url, name)),
+                ItemType::Union => self.unions.insert(ItemEntry::new(new_url, name)),
+                ItemType::Primitive => self.primitives.insert(ItemEntry::new(new_url, name)),
+                ItemType::Trait => self.traits.insert(ItemEntry::new(new_url, name)),
+                ItemType::Macro => self.macros.insert(ItemEntry::new(new_url, name)),
+                ItemType::Function => self.functions.insert(ItemEntry::new(new_url, name)),
+                ItemType::Typedef => self.typedefs.insert(ItemEntry::new(new_url, name)),
+                ItemType::OpaqueTy => self.opaque_tys.insert(ItemEntry::new(new_url, name)),
+                ItemType::Static => self.statics.insert(ItemEntry::new(new_url, name)),
+                ItemType::Constant => self.constants.insert(ItemEntry::new(new_url, name)),
+                ItemType::ProcAttribute => self.attributes.insert(ItemEntry::new(new_url, name)),
+                ItemType::ProcDerive => self.derives.insert(ItemEntry::new(new_url, name)),
+                ItemType::TraitAlias => self.trait_aliases.insert(ItemEntry::new(new_url, name)),
+                _ => true,
+            };
+        }
+    }
+}
+
+fn print_entries(f: &mut Buffer, e: &FxHashSet<ItemEntry>, title: &str, class: &str) {
+    if !e.is_empty() {
+        let mut e: Vec<&ItemEntry> = e.iter().collect();
+        e.sort();
+        write!(
+            f,
+            "<h3 id='{}'>{}</h3><ul class='{} docblock'>{}</ul>",
+            title,
+            Escape(title),
+            class,
+            e.iter().map(|s| format!("<li>{}</li>", s.print())).collect::<String>()
+        );
+    }
+}
+
+impl AllTypes {
+    fn print(self, f: &mut Buffer) {
+        write!(
+            f,
+            "<h1 class='fqn'>\
+        <span class='out-of-band'>\
+            <span id='render-detail'>\
+                <a id=\"toggle-all-docs\" href=\"javascript:void(0)\" title=\"collapse all docs\">\
+                    [<span class='inner'>&#x2212;</span>]\
+                </a>\
+            </span>
+        </span>
+        <span class='in-band'>List of all items</span>\
+    </h1>"
+        );
+        print_entries(f, &self.structs, "Structs", "structs");
+        print_entries(f, &self.enums, "Enums", "enums");
+        print_entries(f, &self.unions, "Unions", "unions");
+        print_entries(f, &self.primitives, "Primitives", "primitives");
+        print_entries(f, &self.traits, "Traits", "traits");
+        print_entries(f, &self.macros, "Macros", "macros");
+        print_entries(f, &self.attributes, "Attribute Macros", "attributes");
+        print_entries(f, &self.derives, "Derive Macros", "derives");
+        print_entries(f, &self.functions, "Functions", "functions");
+        print_entries(f, &self.typedefs, "Typedefs", "typedefs");
+        print_entries(f, &self.trait_aliases, "Trait Aliases", "trait-aliases");
+        print_entries(f, &self.opaque_tys, "Opaque Types", "opaque-types");
+        print_entries(f, &self.statics, "Statics", "statics");
+        print_entries(f, &self.constants, "Constants", "constants")
+    }
+}
+
+#[derive(Debug)]
+enum Setting {
+    Section { description: &'static str, sub_settings: Vec<Setting> },
+    Entry { js_data_name: &'static str, description: &'static str, default_value: bool },
+}
+
+impl Setting {
+    fn display(&self) -> String {
+        match *self {
+            Setting::Section { ref description, ref sub_settings } => format!(
+                "<div class='setting-line'>\
+                        <div class='title'>{}</div>\
+                        <div class='sub-settings'>{}</div>
+                    </div>",
+                description,
+                sub_settings.iter().map(|s| s.display()).collect::<String>()
+            ),
+            Setting::Entry { ref js_data_name, ref description, ref default_value } => format!(
+                "<div class='setting-line'>\
+                        <label class='toggle'>\
+                        <input type='checkbox' id='{}' {}>\
+                        <span class='slider'></span>\
+                        </label>\
+                        <div>{}</div>\
+                    </div>",
+                js_data_name,
+                if *default_value { " checked" } else { "" },
+                description,
+            ),
+        }
+    }
+}
+
+impl From<(&'static str, &'static str, bool)> for Setting {
+    fn from(values: (&'static str, &'static str, bool)) -> Setting {
+        Setting::Entry { js_data_name: values.0, description: values.1, default_value: values.2 }
+    }
+}
+
+impl<T: Into<Setting>> From<(&'static str, Vec<T>)> for Setting {
+    fn from(values: (&'static str, Vec<T>)) -> Setting {
+        Setting::Section {
+            description: values.0,
+            sub_settings: values.1.into_iter().map(|v| v.into()).collect::<Vec<_>>(),
+        }
+    }
+}
+
+fn settings(root_path: &str, suffix: &str) -> String {
+    // (id, explanation, default value)
+    let settings: &[Setting] = &[
+        (
+            "Auto-hide item declarations",
+            vec![
+                ("auto-hide-struct", "Auto-hide structs declaration", true),
+                ("auto-hide-enum", "Auto-hide enums declaration", false),
+                ("auto-hide-union", "Auto-hide unions declaration", true),
+                ("auto-hide-trait", "Auto-hide traits declaration", true),
+                ("auto-hide-macro", "Auto-hide macros declaration", false),
+            ],
+        )
+            .into(),
+        ("auto-hide-attributes", "Auto-hide item attributes.", true).into(),
+        ("auto-hide-method-docs", "Auto-hide item methods' documentation", false).into(),
+        ("auto-hide-trait-implementations", "Auto-hide trait implementation documentation", true)
+            .into(),
+        ("auto-collapse-implementors", "Auto-hide implementors of a trait", true).into(),
+        ("go-to-only-result", "Directly go to item in search if there is only one result", false)
+            .into(),
+        ("line-numbers", "Show line numbers on code examples", false).into(),
+        ("disable-shortcuts", "Disable keyboard shortcuts", false).into(),
+    ];
+    format!(
+        "<h1 class='fqn'>\
+    <span class='in-band'>Rustdoc settings</span>\
+</h1>\
+<div class='settings'>{}</div>\
+<script src='{}settings{}.js'></script>",
+        settings.iter().map(|s| s.display()).collect::<String>(),
+        root_path,
+        suffix
+    )
+}
+
+impl Context {
+    fn derive_id(&self, id: String) -> String {
+        let mut map = self.id_map.borrow_mut();
+        map.derive(id)
+    }
+
+    /// String representation of how to get back to the root path of the 'doc/'
+    /// folder in terms of a relative URL.
+    fn root_path(&self) -> String {
+        "../".repeat(self.current.len())
+    }
+
+    fn render_item(&self, it: &clean::Item, pushname: bool, cache: &Cache) -> String {
+        // A little unfortunate that this is done like this, but it sure
+        // does make formatting *a lot* nicer.
+        CURRENT_DEPTH.with(|slot| {
+            slot.set(self.current.len());
+        });
+
+        let mut title = if it.is_primitive() || it.is_keyword() {
+            // No need to include the namespace for primitive types and keywords
+            String::new()
+        } else {
+            self.current.join("::")
+        };
+        if pushname {
+            if !title.is_empty() {
+                title.push_str("::");
+            }
+            title.push_str(it.name.as_ref().unwrap());
+        }
+        title.push_str(" - Rust");
+        let tyname = it.type_();
+        let desc = if it.is_crate() {
+            format!("API documentation for the Rust `{}` crate.", self.shared.layout.krate)
+        } else {
+            format!(
+                "API documentation for the Rust `{}` {} in crate `{}`.",
+                it.name.as_ref().unwrap(),
+                tyname,
+                self.shared.layout.krate
+            )
+        };
+        let keywords = make_item_keywords(it);
+        let page = layout::Page {
+            css_class: tyname.as_str(),
+            root_path: &self.root_path(),
+            static_root_path: self.shared.static_root_path.as_deref(),
+            title: &title,
+            description: &desc,
+            keywords: &keywords,
+            resource_suffix: &self.shared.resource_suffix,
+            extra_scripts: &[],
+            static_extra_scripts: &[],
+        };
+
+        {
+            self.id_map.borrow_mut().reset();
+            self.id_map.borrow_mut().populate(initial_ids());
+        }
+
+        if !self.render_redirect_pages {
+            layout::render(
+                &self.shared.layout,
+                &page,
+                |buf: &mut _| print_sidebar(self, it, buf, cache),
+                |buf: &mut _| print_item(self, it, buf, cache),
+                &self.shared.style_files,
+            )
+        } else {
+            let mut url = self.root_path();
+            if let Some(&(ref names, ty)) = cache.paths.get(&it.def_id) {
+                for name in &names[..names.len() - 1] {
+                    url.push_str(name);
+                    url.push_str("/");
+                }
+                url.push_str(&item_path(ty, names.last().unwrap()));
+                layout::redirect(&url)
+            } else {
+                String::new()
+            }
+        }
+    }
+
+    fn build_sidebar_items(&self, m: &clean::Module) -> BTreeMap<String, Vec<NameDoc>> {
+        // BTreeMap instead of HashMap to get a sorted output
+        let mut map: BTreeMap<_, Vec<_>> = BTreeMap::new();
+        for item in &m.items {
+            if item.is_stripped() {
+                continue;
+            }
+
+            let short = item.type_();
+            let myname = match item.name {
+                None => continue,
+                Some(ref s) => s.to_string(),
+            };
+            let short = short.to_string();
+            map.entry(short)
+                .or_default()
+                .push((myname, Some(plain_summary_line(item.doc_value()))));
+        }
+
+        if self.shared.sort_modules_alphabetically {
+            for items in map.values_mut() {
+                items.sort();
+            }
+        }
+        map
+    }
+
+    /// Generates a url appropriate for an `href` attribute back to the source of
+    /// this item.
+    ///
+    /// The url generated, when clicked, will redirect the browser back to the
+    /// original source code.
+    ///
+    /// If `None` is returned, then a source link couldn't be generated. This
+    /// may happen, for example, with externally inlined items where the source
+    /// of their crate documentation isn't known.
+    fn src_href(&self, item: &clean::Item, cache: &Cache) -> Option<String> {
+        let mut root = self.root_path();
+
+        let mut path = String::new();
+
+        // We can safely ignore synthetic `SourceFile`s.
+        let file = match item.source.filename {
+            FileName::Real(ref path) => path.local_path().to_path_buf(),
+            _ => return None,
+        };
+        let file = &file;
+
+        let (krate, path) = if item.source.cnum == LOCAL_CRATE {
+            if let Some(path) = self.shared.local_sources.get(file) {
+                (&self.shared.layout.krate, path)
+            } else {
+                return None;
+            }
+        } else {
+            let (krate, src_root) = match *cache.extern_locations.get(&item.source.cnum)? {
+                (ref name, ref src, ExternalLocation::Local) => (name, src),
+                (ref name, ref src, ExternalLocation::Remote(ref s)) => {
+                    root = s.to_string();
+                    (name, src)
+                }
+                (_, _, ExternalLocation::Unknown) => return None,
+            };
+
+            sources::clean_path(&src_root, file, false, |component| {
+                path.push_str(&component.to_string_lossy());
+                path.push('/');
+            });
+            let mut fname = file.file_name().expect("source has no filename").to_os_string();
+            fname.push(".html");
+            path.push_str(&fname.to_string_lossy());
+            (krate, &path)
+        };
+
+        let lines = if item.source.loline == item.source.hiline {
+            item.source.loline.to_string()
+        } else {
+            format!("{}-{}", item.source.loline, item.source.hiline)
+        };
+        Some(format!(
+            "{root}src/{krate}/{path}#{lines}",
+            root = Escape(&root),
+            krate = krate,
+            path = path,
+            lines = lines
+        ))
+    }
+}
+
+fn wrap_into_docblock<F>(w: &mut Buffer, f: F)
+where
+    F: FnOnce(&mut Buffer),
+{
+    write!(w, "<div class=\"docblock type-decl hidden-by-usual-hider\">");
+    f(w);
+    write!(w, "</div>")
+}
+
+fn print_item(cx: &Context, item: &clean::Item, buf: &mut Buffer, cache: &Cache) {
+    debug_assert!(!item.is_stripped());
+    // Write the breadcrumb trail header for the top
+    write!(buf, "<h1 class='fqn'><span class='out-of-band'>");
+    if let Some(version) = item.stable_since() {
+        write!(
+            buf,
+            "<span class='since' title='Stable since Rust version {0}'>{0}</span>",
+            version
+        );
+    }
+    write!(
+        buf,
+        "<span id='render-detail'>\
+                <a id=\"toggle-all-docs\" href=\"javascript:void(0)\" \
+                    title=\"collapse all docs\">\
+                    [<span class='inner'>&#x2212;</span>]\
+                </a>\
+            </span>"
+    );
+
+    // Write `src` tag
+    //
+    // When this item is part of a `pub use` in a downstream crate, the
+    // [src] link in the downstream documentation will actually come back to
+    // this page, and this link will be auto-clicked. The `id` attribute is
+    // used to find the link to auto-click.
+    if cx.shared.include_sources && !item.is_primitive() {
+        if let Some(l) = cx.src_href(item, cache) {
+            write!(buf, "<a class='srclink' href='{}' title='{}'>[src]</a>", l, "goto source code");
+        }
+    }
+
+    write!(buf, "</span>"); // out-of-band
+    write!(buf, "<span class='in-band'>");
+    let name = match item.inner {
+        clean::ModuleItem(ref m) => {
+            if m.is_crate {
+                "Crate "
+            } else {
+                "Module "
+            }
+        }
+        clean::FunctionItem(..) | clean::ForeignFunctionItem(..) => "Function ",
+        clean::TraitItem(..) => "Trait ",
+        clean::StructItem(..) => "Struct ",
+        clean::UnionItem(..) => "Union ",
+        clean::EnumItem(..) => "Enum ",
+        clean::TypedefItem(..) => "Type Definition ",
+        clean::MacroItem(..) => "Macro ",
+        clean::ProcMacroItem(ref mac) => match mac.kind {
+            MacroKind::Bang => "Macro ",
+            MacroKind::Attr => "Attribute Macro ",
+            MacroKind::Derive => "Derive Macro ",
+        },
+        clean::PrimitiveItem(..) => "Primitive Type ",
+        clean::StaticItem(..) | clean::ForeignStaticItem(..) => "Static ",
+        clean::ConstantItem(..) => "Constant ",
+        clean::ForeignTypeItem => "Foreign Type ",
+        clean::KeywordItem(..) => "Keyword ",
+        clean::OpaqueTyItem(..) => "Opaque Type ",
+        clean::TraitAliasItem(..) => "Trait Alias ",
+        _ => {
+            // We don't generate pages for any other type.
+            unreachable!();
+        }
+    };
+    buf.write_str(name);
+    if !item.is_primitive() && !item.is_keyword() {
+        let cur = &cx.current;
+        let amt = if item.is_mod() { cur.len() - 1 } else { cur.len() };
+        for (i, component) in cur.iter().enumerate().take(amt) {
+            write!(
+                buf,
+                "<a href='{}index.html'>{}</a>::<wbr>",
+                "../".repeat(cur.len() - i - 1),
+                component
+            );
+        }
+    }
+    write!(buf, "<a class=\"{}\" href=''>{}</a>", item.type_(), item.name.as_ref().unwrap());
+
+    write!(buf, "</span></h1>"); // in-band
+
+    match item.inner {
+        clean::ModuleItem(ref m) => item_module(buf, cx, item, &m.items),
+        clean::FunctionItem(ref f) | clean::ForeignFunctionItem(ref f) => {
+            item_function(buf, cx, item, f)
+        }
+        clean::TraitItem(ref t) => item_trait(buf, cx, item, t, cache),
+        clean::StructItem(ref s) => item_struct(buf, cx, item, s, cache),
+        clean::UnionItem(ref s) => item_union(buf, cx, item, s, cache),
+        clean::EnumItem(ref e) => item_enum(buf, cx, item, e, cache),
+        clean::TypedefItem(ref t, _) => item_typedef(buf, cx, item, t, cache),
+        clean::MacroItem(ref m) => item_macro(buf, cx, item, m),
+        clean::ProcMacroItem(ref m) => item_proc_macro(buf, cx, item, m),
+        clean::PrimitiveItem(_) => item_primitive(buf, cx, item, cache),
+        clean::StaticItem(ref i) | clean::ForeignStaticItem(ref i) => item_static(buf, cx, item, i),
+        clean::ConstantItem(ref c) => item_constant(buf, cx, item, c),
+        clean::ForeignTypeItem => item_foreign_type(buf, cx, item, cache),
+        clean::KeywordItem(_) => item_keyword(buf, cx, item),
+        clean::OpaqueTyItem(ref e, _) => item_opaque_ty(buf, cx, item, e, cache),
+        clean::TraitAliasItem(ref ta) => item_trait_alias(buf, cx, item, ta, cache),
+        _ => {
+            // We don't generate pages for any other type.
+            unreachable!();
+        }
+    }
+}
+
+fn item_path(ty: ItemType, name: &str) -> String {
+    match ty {
+        ItemType::Module => format!("{}index.html", ensure_trailing_slash(name)),
+        _ => format!("{}.{}.html", ty, name),
+    }
+}
+
+fn full_path(cx: &Context, item: &clean::Item) -> String {
+    let mut s = cx.current.join("::");
+    s.push_str("::");
+    s.push_str(item.name.as_ref().unwrap());
+    s
+}
+
+#[inline]
+crate fn plain_summary_line(s: Option<&str>) -> String {
+    let s = s.unwrap_or("");
+    // This essentially gets the first paragraph of text in one line.
+    let mut line = s
+        .lines()
+        .skip_while(|line| line.chars().all(|c| c.is_whitespace()))
+        .take_while(|line| line.chars().any(|c| !c.is_whitespace()))
+        .fold(String::new(), |mut acc, line| {
+            acc.push_str(line);
+            acc.push(' ');
+            acc
+        });
+    // remove final whitespace
+    line.pop();
+    markdown::plain_summary_line(&line[..])
+}
+
+crate fn shorten(s: String) -> String {
+    if s.chars().count() > 60 {
+        let mut len = 0;
+        let mut ret = s
+            .split_whitespace()
+            .take_while(|p| {
+                // + 1 for the added character after the word.
+                len += p.chars().count() + 1;
+                len < 60
+            })
+            .collect::<Vec<_>>()
+            .join(" ");
+        ret.push('…');
+        ret
+    } else {
+        s
+    }
+}
+
+fn document(w: &mut Buffer, cx: &Context, item: &clean::Item) {
+    if let Some(ref name) = item.name {
+        info!("Documenting {}", name);
+    }
+    document_stability(w, cx, item, false);
+    document_full(w, item, cx, "", false);
+}
+
+/// Render md_text as markdown.
+fn render_markdown(
+    w: &mut Buffer,
+    cx: &Context,
+    md_text: &str,
+    links: Vec<(String, String)>,
+    prefix: &str,
+    is_hidden: bool,
+) {
+    let mut ids = cx.id_map.borrow_mut();
+    write!(
+        w,
+        "<div class='docblock{}'>{}{}</div>",
+        if is_hidden { " hidden" } else { "" },
+        prefix,
+        Markdown(
+            md_text,
+            &links,
+            &mut ids,
+            cx.shared.codes,
+            cx.shared.edition,
+            &cx.shared.playground
+        )
+        .into_string()
+    )
+}
+
+fn document_short(
+    w: &mut Buffer,
+    cx: &Context,
+    item: &clean::Item,
+    link: AssocItemLink<'_>,
+    prefix: &str,
+    is_hidden: bool,
+) {
+    if let Some(s) = item.doc_value() {
+        let markdown = if s.contains('\n') {
+            format!(
+                "{} [Read more]({})",
+                &plain_summary_line(Some(s)),
+                naive_assoc_href(item, link)
+            )
+        } else {
+            plain_summary_line(Some(s))
+        };
+        render_markdown(w, cx, &markdown, item.links(), prefix, is_hidden);
+    } else if !prefix.is_empty() {
+        write!(
+            w,
+            "<div class='docblock{}'>{}</div>",
+            if is_hidden { " hidden" } else { "" },
+            prefix
+        );
+    }
+}
+
+fn document_full(w: &mut Buffer, item: &clean::Item, cx: &Context, prefix: &str, is_hidden: bool) {
+    if let Some(s) = cx.shared.maybe_collapsed_doc_value(item) {
+        debug!("Doc block: =====\n{}\n=====", s);
+        render_markdown(w, cx, &*s, item.links(), prefix, is_hidden);
+    } else if !prefix.is_empty() {
+        write!(
+            w,
+            "<div class='docblock{}'>{}</div>",
+            if is_hidden { " hidden" } else { "" },
+            prefix
+        );
+    }
+}
+
+fn document_stability(w: &mut Buffer, cx: &Context, item: &clean::Item, is_hidden: bool) {
+    let stabilities = short_stability(item, cx);
+    if !stabilities.is_empty() {
+        write!(w, "<div class='stability{}'>", if is_hidden { " hidden" } else { "" });
+        for stability in stabilities {
+            write!(w, "{}", stability);
+        }
+        write!(w, "</div>");
+    }
+}
+
+fn document_non_exhaustive_header(item: &clean::Item) -> &str {
+    if item.is_non_exhaustive() { " (Non-exhaustive)" } else { "" }
+}
+
+fn document_non_exhaustive(w: &mut Buffer, item: &clean::Item) {
+    if item.is_non_exhaustive() {
+        write!(w, "<div class='docblock non-exhaustive non-exhaustive-{}'>", {
+            if item.is_struct() {
+                "struct"
+            } else if item.is_enum() {
+                "enum"
+            } else if item.is_variant() {
+                "variant"
+            } else {
+                "type"
+            }
+        });
+
+        if item.is_struct() {
+            write!(
+                w,
+                "Non-exhaustive structs could have additional fields added in future. \
+                       Therefore, non-exhaustive structs cannot be constructed in external crates \
+                       using the traditional <code>Struct {{ .. }}</code> syntax; cannot be \
+                       matched against without a wildcard <code>..</code>; and \
+                       struct update syntax will not work."
+            );
+        } else if item.is_enum() {
+            write!(
+                w,
+                "Non-exhaustive enums could have additional variants added in future. \
+                       Therefore, when matching against variants of non-exhaustive enums, an \
+                       extra wildcard arm must be added to account for any future variants."
+            );
+        } else if item.is_variant() {
+            write!(
+                w,
+                "Non-exhaustive enum variants could have additional fields added in future. \
+                       Therefore, non-exhaustive enum variants cannot be constructed in external \
+                       crates and cannot be matched against."
+            );
+        } else {
+            write!(
+                w,
+                "This type will require a wildcard arm in any match statements or \
+                       constructors."
+            );
+        }
+
+        write!(w, "</div>");
+    }
+}
+
+fn name_key(name: &str) -> (&str, u64, usize) {
+    let end = name.bytes().rposition(|b| b.is_ascii_digit()).map_or(name.len(), |i| i + 1);
+
+    // find number at end
+    let split = name[0..end].bytes().rposition(|b| !b.is_ascii_digit()).map_or(0, |i| i + 1);
+
+    // count leading zeroes
+    let after_zeroes =
+        name[split..end].bytes().position(|b| b != b'0').map_or(name.len(), |extra| split + extra);
+
+    // sort leading zeroes last
+    let num_zeroes = after_zeroes - split;
+
+    match name[split..end].parse() {
+        Ok(n) => (&name[..split], n, num_zeroes),
+        Err(_) => (name, 0, num_zeroes),
+    }
+}
+
+fn item_module(w: &mut Buffer, cx: &Context, item: &clean::Item, items: &[clean::Item]) {
+    document(w, cx, item);
+
+    let mut indices = (0..items.len()).filter(|i| !items[*i].is_stripped()).collect::<Vec<usize>>();
+
+    // the order of item types in the listing
+    fn reorder(ty: ItemType) -> u8 {
+        match ty {
+            ItemType::ExternCrate => 0,
+            ItemType::Import => 1,
+            ItemType::Primitive => 2,
+            ItemType::Module => 3,
+            ItemType::Macro => 4,
+            ItemType::Struct => 5,
+            ItemType::Enum => 6,
+            ItemType::Constant => 7,
+            ItemType::Static => 8,
+            ItemType::Trait => 9,
+            ItemType::Function => 10,
+            ItemType::Typedef => 12,
+            ItemType::Union => 13,
+            _ => 14 + ty as u8,
+        }
+    }
+
+    fn cmp(i1: &clean::Item, i2: &clean::Item, idx1: usize, idx2: usize) -> Ordering {
+        let ty1 = i1.type_();
+        let ty2 = i2.type_();
+        if ty1 != ty2 {
+            return (reorder(ty1), idx1).cmp(&(reorder(ty2), idx2));
+        }
+        let s1 = i1.stability.as_ref().map(|s| s.level);
+        let s2 = i2.stability.as_ref().map(|s| s.level);
+        match (s1, s2) {
+            (Some(stability::Unstable), Some(stability::Stable)) => return Ordering::Greater,
+            (Some(stability::Stable), Some(stability::Unstable)) => return Ordering::Less,
+            _ => {}
+        }
+        let lhs = i1.name.as_ref().map_or("", |s| &**s);
+        let rhs = i2.name.as_ref().map_or("", |s| &**s);
+        name_key(lhs).cmp(&name_key(rhs))
+    }
+
+    if cx.shared.sort_modules_alphabetically {
+        indices.sort_by(|&i1, &i2| cmp(&items[i1], &items[i2], i1, i2));
+    }
+    // This call is to remove re-export duplicates in cases such as:
+    //
+    // ```
+    // pub mod foo {
+    //     pub mod bar {
+    //         pub trait Double { fn foo(); }
+    //     }
+    // }
+    //
+    // pub use foo::bar::*;
+    // pub use foo::*;
+    // ```
+    //
+    // `Double` will appear twice in the generated docs.
+    //
+    // FIXME: This code is quite ugly and could be improved. Small issue: DefId
+    // can be identical even if the elements are different (mostly in imports).
+    // So in case this is an import, we keep everything by adding a "unique id"
+    // (which is the position in the vector).
+    indices.dedup_by_key(|i| {
+        (
+            items[*i].def_id,
+            if items[*i].name.as_ref().is_some() { Some(full_path(cx, &items[*i])) } else { None },
+            items[*i].type_(),
+            if items[*i].is_import() { *i } else { 0 },
+        )
+    });
+
+    debug!("{:?}", indices);
+    let mut curty = None;
+    for &idx in &indices {
+        let myitem = &items[idx];
+        if myitem.is_stripped() {
+            continue;
+        }
+
+        let myty = Some(myitem.type_());
+        if curty == Some(ItemType::ExternCrate) && myty == Some(ItemType::Import) {
+            // Put `extern crate` and `use` re-exports in the same section.
+            curty = myty;
+        } else if myty != curty {
+            if curty.is_some() {
+                write!(w, "</table>");
+            }
+            curty = myty;
+            let (short, name) = item_ty_to_strs(&myty.unwrap());
+            write!(
+                w,
+                "<h2 id='{id}' class='section-header'>\
+                       <a href=\"#{id}\">{name}</a></h2>\n<table>",
+                id = cx.derive_id(short.to_owned()),
+                name = name
+            );
+        }
+
+        match myitem.inner {
+            clean::ExternCrateItem(ref name, ref src) => {
+                use crate::html::format::anchor;
+
+                match *src {
+                    Some(ref src) => write!(
+                        w,
+                        "<tr><td><code>{}extern crate {} as {};",
+                        myitem.visibility.print_with_space(),
+                        anchor(myitem.def_id, src),
+                        name
+                    ),
+                    None => write!(
+                        w,
+                        "<tr><td><code>{}extern crate {};",
+                        myitem.visibility.print_with_space(),
+                        anchor(myitem.def_id, name)
+                    ),
+                }
+                write!(w, "</code></td></tr>");
+            }
+
+            clean::ImportItem(ref import) => {
+                write!(
+                    w,
+                    "<tr><td><code>{}{}</code></td></tr>",
+                    myitem.visibility.print_with_space(),
+                    import.print()
+                );
+            }
+
+            _ => {
+                if myitem.name.is_none() {
+                    continue;
+                }
+
+                let unsafety_flag = match myitem.inner {
+                    clean::FunctionItem(ref func) | clean::ForeignFunctionItem(ref func)
+                        if func.header.unsafety == hir::Unsafety::Unsafe =>
+                    {
+                        "<a title='unsafe function' href='#'><sup>⚠</sup></a>"
+                    }
+                    _ => "",
+                };
+
+                let stab = myitem.stability_class();
+                let add = if stab.is_some() { " " } else { "" };
+
+                let doc_value = myitem.doc_value().unwrap_or("");
+                write!(
+                    w,
+                    "\
+                       <tr class='{stab}{add}module-item'>\
+                           <td><a class=\"{class}\" href=\"{href}\" \
+                                  title='{title}'>{name}</a>{unsafety_flag}</td>\
+                           <td class='docblock-short'>{stab_tags}{docs}</td>\
+                       </tr>",
+                    name = *myitem.name.as_ref().unwrap(),
+                    stab_tags = stability_tags(myitem),
+                    docs = MarkdownSummaryLine(doc_value, &myitem.links()).into_string(),
+                    class = myitem.type_(),
+                    add = add,
+                    stab = stab.unwrap_or_else(String::new),
+                    unsafety_flag = unsafety_flag,
+                    href = item_path(myitem.type_(), myitem.name.as_ref().unwrap()),
+                    title = [full_path(cx, myitem), myitem.type_().to_string()]
+                        .iter()
+                        .filter_map(|s| if !s.is_empty() { Some(s.as_str()) } else { None })
+                        .collect::<Vec<_>>()
+                        .join(" "),
+                );
+            }
+        }
+    }
+
+    if curty.is_some() {
+        write!(w, "</table>");
+    }
+}
+
+/// Render the stability and deprecation tags that are displayed in the item's summary at the
+/// module level.
+fn stability_tags(item: &clean::Item) -> String {
+    let mut tags = String::new();
+
+    fn tag_html(class: &str, contents: &str) -> String {
+        format!(r#"<span class="stab {}">{}</span>"#, class, contents)
+    }
+
+    // The trailing space after each tag is to space it properly against the rest of the docs.
+    if let Some(depr) = &item.deprecation {
+        let mut message = "Deprecated";
+        if !stability::deprecation_in_effect(depr.is_since_rustc_version, depr.since.as_deref()) {
+            message = "Deprecation planned";
+        }
+        tags += &tag_html("deprecated", message);
+    }
+
+    // The "rustc_private" crates are permanently unstable so it makes no sense
+    // to render "unstable" everywhere.
+    if item
+        .stability
+        .as_ref()
+        .map(|s| s.level == stability::Unstable && s.feature.as_deref() != Some("rustc_private"))
+        == Some(true)
+    {
+        tags += &tag_html("unstable", "Experimental");
+    }
+
+    if let Some(ref cfg) = item.attrs.cfg {
+        tags += &tag_html("portability", &cfg.render_short_html());
+    }
+
+    tags
+}
+
+/// Render the stability and/or deprecation warning that is displayed at the top of the item's
+/// documentation.
+fn short_stability(item: &clean::Item, cx: &Context) -> Vec<String> {
+    let mut stability = vec![];
+    let error_codes = cx.shared.codes;
+
+    if let Some(Deprecation { ref note, ref since, is_since_rustc_version }) = item.deprecation {
+        // We display deprecation messages for #[deprecated] and #[rustc_deprecated]
+        // but only display the future-deprecation messages for #[rustc_deprecated].
+        let mut message = if let Some(since) = since {
+            if !stability::deprecation_in_effect(is_since_rustc_version, Some(since)) {
+                format!("Deprecating in {}", Escape(&since))
+            } else {
+                format!("Deprecated since {}", Escape(&since))
+            }
+        } else {
+            String::from("Deprecated")
+        };
+
+        if let Some(note) = note {
+            let mut ids = cx.id_map.borrow_mut();
+            let html = MarkdownHtml(
+                &note,
+                &mut ids,
+                error_codes,
+                cx.shared.edition,
+                &cx.shared.playground,
+            );
+            message.push_str(&format!(": {}", html.into_string()));
+        }
+        stability.push(format!(
+            "<div class='stab deprecated'><span class='emoji'>👎</span> {}</div>",
+            message,
+        ));
+    }
+
+    // Render unstable items. But don't render "rustc_private" crates (internal compiler crates).
+    // Those crates are permanently unstable so it makes no sense to render "unstable" everywhere.
+    if let Some(stab) = item.stability.as_ref().filter(|stab| {
+        stab.level == stability::Unstable && stab.feature.as_deref() != Some("rustc_private")
+    }) {
+        let mut message =
+            "<span class='emoji'>🔬</span> This is a nightly-only experimental API.".to_owned();
+
+        if let Some(feature) = stab.feature.as_deref() {
+            let mut feature = format!("<code>{}</code>", Escape(&feature));
+            if let (Some(url), Some(issue)) = (&cx.shared.issue_tracker_base_url, stab.issue) {
+                feature.push_str(&format!(
+                    "&nbsp;<a href=\"{url}{issue}\">#{issue}</a>",
+                    url = url,
+                    issue = issue
+                ));
+            }
+
+            message.push_str(&format!(" ({})", feature));
+        }
+
+        if let Some(unstable_reason) = &stab.unstable_reason {
+            let mut ids = cx.id_map.borrow_mut();
+            message = format!(
+                "<details><summary>{}</summary>{}</details>",
+                message,
+                MarkdownHtml(
+                    &unstable_reason,
+                    &mut ids,
+                    error_codes,
+                    cx.shared.edition,
+                    &cx.shared.playground,
+                )
+                .into_string()
+            );
+        }
+
+        stability.push(format!("<div class='stab unstable'>{}</div>", message));
+    }
+
+    if let Some(ref cfg) = item.attrs.cfg {
+        stability.push(format!("<div class='stab portability'>{}</div>", cfg.render_long_html()));
+    }
+
+    stability
+}
+
+fn item_constant(w: &mut Buffer, cx: &Context, it: &clean::Item, c: &clean::Constant) {
+    write!(w, "<pre class='rust const'>");
+    render_attributes(w, it, false);
+
+    write!(
+        w,
+        "{vis}const \
+               {name}: {typ}",
+        vis = it.visibility.print_with_space(),
+        name = it.name.as_ref().unwrap(),
+        typ = c.type_.print(),
+    );
+
+    if c.value.is_some() || c.is_literal {
+        write!(w, " = {expr};", expr = Escape(&c.expr));
+    } else {
+        write!(w, ";");
+    }
+
+    if let Some(value) = &c.value {
+        if !c.is_literal {
+            let value_lowercase = value.to_lowercase();
+            let expr_lowercase = c.expr.to_lowercase();
+
+            if value_lowercase != expr_lowercase
+                && value_lowercase.trim_end_matches("i32") != expr_lowercase
+            {
+                write!(w, " // {value}", value = Escape(value));
+            }
+        }
+    }
+
+    write!(w, "</pre>");
+    document(w, cx, it)
+}
+
+fn item_static(w: &mut Buffer, cx: &Context, it: &clean::Item, s: &clean::Static) {
+    write!(w, "<pre class='rust static'>");
+    render_attributes(w, it, false);
+    write!(
+        w,
+        "{vis}static {mutability}\
+               {name}: {typ}</pre>",
+        vis = it.visibility.print_with_space(),
+        mutability = s.mutability.print_with_space(),
+        name = it.name.as_ref().unwrap(),
+        typ = s.type_.print()
+    );
+    document(w, cx, it)
+}
+
+fn item_function(w: &mut Buffer, cx: &Context, it: &clean::Item, f: &clean::Function) {
+    let header_len = format!(
+        "{}{}{}{}{:#}fn {}{:#}",
+        it.visibility.print_with_space(),
+        f.header.constness.print_with_space(),
+        f.header.asyncness.print_with_space(),
+        f.header.unsafety.print_with_space(),
+        print_abi_with_space(f.header.abi),
+        it.name.as_ref().unwrap(),
+        f.generics.print()
+    )
+    .len();
+    write!(w, "<pre class='rust fn'>");
+    render_attributes(w, it, false);
+    write!(
+        w,
+        "{vis}{constness}{asyncness}{unsafety}{abi}fn \
+           {name}{generics}{decl}{spotlight}{where_clause}</pre>",
+        vis = it.visibility.print_with_space(),
+        constness = f.header.constness.print_with_space(),
+        asyncness = f.header.asyncness.print_with_space(),
+        unsafety = f.header.unsafety.print_with_space(),
+        abi = print_abi_with_space(f.header.abi),
+        name = it.name.as_ref().unwrap(),
+        generics = f.generics.print(),
+        where_clause = WhereClause { gens: &f.generics, indent: 0, end_newline: true },
+        decl = Function { decl: &f.decl, header_len, indent: 0, asyncness: f.header.asyncness }
+            .print(),
+        spotlight = spotlight_decl(&f.decl),
+    );
+    document(w, cx, it)
+}
+
+fn render_implementor(
+    cx: &Context,
+    implementor: &Impl,
+    w: &mut Buffer,
+    implementor_dups: &FxHashMap<&str, (DefId, bool)>,
+    aliases: &[String],
+    cache: &Cache,
+) {
+    // If there's already another implementor that has the same abbridged name, use the
+    // full path, for example in `std::iter::ExactSizeIterator`
+    let use_absolute = match implementor.inner_impl().for_ {
+        clean::ResolvedPath { ref path, is_generic: false, .. }
+        | clean::BorrowedRef {
+            type_: box clean::ResolvedPath { ref path, is_generic: false, .. },
+            ..
+        } => implementor_dups[path.last_name()].1,
+        _ => false,
+    };
+    render_impl(
+        w,
+        cx,
+        implementor,
+        AssocItemLink::Anchor(None),
+        RenderMode::Normal,
+        implementor.impl_item.stable_since(),
+        false,
+        Some(use_absolute),
+        false,
+        false,
+        aliases,
+        cache,
+    );
+}
+
+fn render_impls(
+    cx: &Context,
+    w: &mut Buffer,
+    traits: &[&&Impl],
+    containing_item: &clean::Item,
+    cache: &Cache,
+) {
+    let mut impls = traits
+        .iter()
+        .map(|i| {
+            let did = i.trait_did().unwrap();
+            let assoc_link = AssocItemLink::GotoSource(did, &i.inner_impl().provided_trait_methods);
+            let mut buffer = if w.is_for_html() { Buffer::html() } else { Buffer::new() };
+            render_impl(
+                &mut buffer,
+                cx,
+                i,
+                assoc_link,
+                RenderMode::Normal,
+                containing_item.stable_since(),
+                true,
+                None,
+                false,
+                true,
+                &[],
+                cache,
+            );
+            buffer.into_inner()
+        })
+        .collect::<Vec<_>>();
+    impls.sort();
+    w.write_str(&impls.join(""));
+}
+
+fn bounds(t_bounds: &[clean::GenericBound], trait_alias: bool) -> String {
+    let mut bounds = String::new();
+    if !t_bounds.is_empty() {
+        if !trait_alias {
+            bounds.push_str(": ");
+        }
+        for (i, p) in t_bounds.iter().enumerate() {
+            if i > 0 {
+                bounds.push_str(" + ");
+            }
+            bounds.push_str(&p.print().to_string());
+        }
+    }
+    bounds
+}
+
+fn compare_impl<'a, 'b>(lhs: &'a &&Impl, rhs: &'b &&Impl) -> Ordering {
+    let lhs = format!("{}", lhs.inner_impl().print());
+    let rhs = format!("{}", rhs.inner_impl().print());
+
+    // lhs and rhs are formatted as HTML, which may be unnecessary
+    name_key(&lhs).cmp(&name_key(&rhs))
+}
+
+fn item_trait(w: &mut Buffer, cx: &Context, it: &clean::Item, t: &clean::Trait, cache: &Cache) {
+    let bounds = bounds(&t.bounds, false);
+    let types = t.items.iter().filter(|m| m.is_associated_type()).collect::<Vec<_>>();
+    let consts = t.items.iter().filter(|m| m.is_associated_const()).collect::<Vec<_>>();
+    let required = t.items.iter().filter(|m| m.is_ty_method()).collect::<Vec<_>>();
+    let provided = t.items.iter().filter(|m| m.is_method()).collect::<Vec<_>>();
+
+    // Output the trait definition
+    wrap_into_docblock(w, |w| {
+        write!(w, "<pre class='rust trait'>");
+        render_attributes(w, it, true);
+        write!(
+            w,
+            "{}{}{}trait {}{}{}",
+            it.visibility.print_with_space(),
+            t.unsafety.print_with_space(),
+            if t.is_auto { "auto " } else { "" },
+            it.name.as_ref().unwrap(),
+            t.generics.print(),
+            bounds
+        );
+
+        if !t.generics.where_predicates.is_empty() {
+            write!(w, "{}", WhereClause { gens: &t.generics, indent: 0, end_newline: true });
+        } else {
+            write!(w, " ");
+        }
+
+        if t.items.is_empty() {
+            write!(w, "{{ }}");
+        } else {
+            // FIXME: we should be using a derived_id for the Anchors here
+            write!(w, "{{\n");
+            for t in &types {
+                render_assoc_item(w, t, AssocItemLink::Anchor(None), ItemType::Trait);
+                write!(w, ";\n");
+            }
+            if !types.is_empty() && !consts.is_empty() {
+                w.write_str("\n");
+            }
+            for t in &consts {
+                render_assoc_item(w, t, AssocItemLink::Anchor(None), ItemType::Trait);
+                write!(w, ";\n");
+            }
+            if !consts.is_empty() && !required.is_empty() {
+                w.write_str("\n");
+            }
+            for (pos, m) in required.iter().enumerate() {
+                render_assoc_item(w, m, AssocItemLink::Anchor(None), ItemType::Trait);
+                write!(w, ";\n");
+
+                if pos < required.len() - 1 {
+                    write!(w, "<div class='item-spacer'></div>");
+                }
+            }
+            if !required.is_empty() && !provided.is_empty() {
+                w.write_str("\n");
+            }
+            for (pos, m) in provided.iter().enumerate() {
+                render_assoc_item(w, m, AssocItemLink::Anchor(None), ItemType::Trait);
+                match m.inner {
+                    clean::MethodItem(ref inner) if !inner.generics.where_predicates.is_empty() => {
+                        write!(w, ",\n    {{ ... }}\n");
+                    }
+                    _ => {
+                        write!(w, " {{ ... }}\n");
+                    }
+                }
+                if pos < provided.len() - 1 {
+                    write!(w, "<div class='item-spacer'></div>");
+                }
+            }
+            write!(w, "}}");
+        }
+        write!(w, "</pre>")
+    });
+
+    // Trait documentation
+    document(w, cx, it);
+
+    fn write_small_section_header(w: &mut Buffer, id: &str, title: &str, extra_content: &str) {
+        write!(
+            w,
+            "
+            <h2 id='{0}' class='small-section-header'>\
+              {1}<a href='#{0}' class='anchor'></a>\
+            </h2>{2}",
+            id, title, extra_content
+        )
+    }
+
+    fn write_loading_content(w: &mut Buffer, extra_content: &str) {
+        write!(w, "{}<span class='loading-content'>Loading content...</span>", extra_content)
+    }
+
+    fn trait_item(w: &mut Buffer, cx: &Context, m: &clean::Item, t: &clean::Item) {
+        let name = m.name.as_ref().unwrap();
+        let item_type = m.type_();
+        let id = cx.derive_id(format!("{}.{}", item_type, name));
+        write!(w, "<h3 id='{id}' class='method'><code>", id = id,);
+        render_assoc_item(w, m, AssocItemLink::Anchor(Some(&id)), ItemType::Impl);
+        write!(w, "</code>");
+        render_stability_since(w, m, t);
+        write!(w, "</h3>");
+        document(w, cx, m);
+    }
+
+    if !types.is_empty() {
+        write_small_section_header(
+            w,
+            "associated-types",
+            "Associated Types",
+            "<div class='methods'>",
+        );
+        for t in &types {
+            trait_item(w, cx, *t, it);
+        }
+        write_loading_content(w, "</div>");
+    }
+
+    if !consts.is_empty() {
+        write_small_section_header(
+            w,
+            "associated-const",
+            "Associated Constants",
+            "<div class='methods'>",
+        );
+        for t in &consts {
+            trait_item(w, cx, *t, it);
+        }
+        write_loading_content(w, "</div>");
+    }
+
+    // Output the documentation for each function individually
+    if !required.is_empty() {
+        write_small_section_header(
+            w,
+            "required-methods",
+            "Required methods",
+            "<div class='methods'>",
+        );
+        for m in &required {
+            trait_item(w, cx, *m, it);
+        }
+        write_loading_content(w, "</div>");
+    }
+    if !provided.is_empty() {
+        write_small_section_header(
+            w,
+            "provided-methods",
+            "Provided methods",
+            "<div class='methods'>",
+        );
+        for m in &provided {
+            trait_item(w, cx, *m, it);
+        }
+        write_loading_content(w, "</div>");
+    }
+
+    // If there are methods directly on this trait object, render them here.
+    render_assoc_items(w, cx, it, it.def_id, AssocItemRender::All, cache);
+
+    if let Some(implementors) = cache.implementors.get(&it.def_id) {
+        // The DefId is for the first Type found with that name. The bool is
+        // if any Types with the same name but different DefId have been found.
+        let mut implementor_dups: FxHashMap<&str, (DefId, bool)> = FxHashMap::default();
+        for implementor in implementors {
+            match implementor.inner_impl().for_ {
+                clean::ResolvedPath { ref path, did, is_generic: false, .. }
+                | clean::BorrowedRef {
+                    type_: box clean::ResolvedPath { ref path, did, is_generic: false, .. },
+                    ..
+                } => {
+                    let &mut (prev_did, ref mut has_duplicates) =
+                        implementor_dups.entry(path.last_name()).or_insert((did, false));
+                    if prev_did != did {
+                        *has_duplicates = true;
+                    }
+                }
+                _ => {}
+            }
+        }
+
+        let (local, foreign) = implementors.iter().partition::<Vec<_>, _>(|i| {
+            i.inner_impl().for_.def_id().map_or(true, |d| cache.paths.contains_key(&d))
+        });
+
+        let (mut synthetic, mut concrete): (Vec<&&Impl>, Vec<&&Impl>) =
+            local.iter().partition(|i| i.inner_impl().synthetic);
+
+        synthetic.sort_by(compare_impl);
+        concrete.sort_by(compare_impl);
+
+        if !foreign.is_empty() {
+            write_small_section_header(w, "foreign-impls", "Implementations on Foreign Types", "");
+
+            for implementor in foreign {
+                let assoc_link = AssocItemLink::GotoSource(
+                    implementor.impl_item.def_id,
+                    &implementor.inner_impl().provided_trait_methods,
+                );
+                render_impl(
+                    w,
+                    cx,
+                    &implementor,
+                    assoc_link,
+                    RenderMode::Normal,
+                    implementor.impl_item.stable_since(),
+                    false,
+                    None,
+                    true,
+                    false,
+                    &[],
+                    cache,
+                );
+            }
+            write_loading_content(w, "");
+        }
+
+        write_small_section_header(
+            w,
+            "implementors",
+            "Implementors",
+            "<div class='item-list' id='implementors-list'>",
+        );
+        for implementor in concrete {
+            render_implementor(cx, implementor, w, &implementor_dups, &[], cache);
+        }
+        write_loading_content(w, "</div>");
+
+        if t.auto {
+            write_small_section_header(
+                w,
+                "synthetic-implementors",
+                "Auto implementors",
+                "<div class='item-list' id='synthetic-implementors-list'>",
+            );
+            for implementor in synthetic {
+                render_implementor(
+                    cx,
+                    implementor,
+                    w,
+                    &implementor_dups,
+                    &collect_paths_for_type(implementor.inner_impl().for_.clone()),
+                    cache,
+                );
+            }
+            write_loading_content(w, "</div>");
+        }
+    } else {
+        // even without any implementations to write in, we still want the heading and list, so the
+        // implementors javascript file pulled in below has somewhere to write the impls into
+        write_small_section_header(
+            w,
+            "implementors",
+            "Implementors",
+            "<div class='item-list' id='implementors-list'>",
+        );
+        write_loading_content(w, "</div>");
+
+        if t.auto {
+            write_small_section_header(
+                w,
+                "synthetic-implementors",
+                "Auto implementors",
+                "<div class='item-list' id='synthetic-implementors-list'>",
+            );
+            write_loading_content(w, "</div>");
+        }
+    }
+
+    write!(
+        w,
+        "<script type=\"text/javascript\" \
+                 src=\"{root_path}/implementors/{path}/{ty}.{name}.js\" async>\
+         </script>",
+        root_path = vec![".."; cx.current.len()].join("/"),
+        path = if it.def_id.is_local() {
+            cx.current.join("/")
+        } else {
+            let (ref path, _) = cache.external_paths[&it.def_id];
+            path[..path.len() - 1].join("/")
+        },
+        ty = it.type_(),
+        name = *it.name.as_ref().unwrap()
+    );
+}
+
+fn naive_assoc_href(it: &clean::Item, link: AssocItemLink<'_>) -> String {
+    use crate::formats::item_type::ItemType::*;
+
+    let name = it.name.as_ref().unwrap();
+    let ty = match it.type_() {
+        Typedef | AssocType => AssocType,
+        s => s,
+    };
+
+    let anchor = format!("#{}.{}", ty, name);
+    match link {
+        AssocItemLink::Anchor(Some(ref id)) => format!("#{}", id),
+        AssocItemLink::Anchor(None) => anchor,
+        AssocItemLink::GotoSource(did, _) => {
+            href(did).map(|p| format!("{}{}", p.0, anchor)).unwrap_or(anchor)
+        }
+    }
+}
+
+fn assoc_const(
+    w: &mut Buffer,
+    it: &clean::Item,
+    ty: &clean::Type,
+    _default: Option<&String>,
+    link: AssocItemLink<'_>,
+    extra: &str,
+) {
+    write!(
+        w,
+        "{}{}const <a href='{}' class=\"constant\"><b>{}</b></a>: {}",
+        extra,
+        it.visibility.print_with_space(),
+        naive_assoc_href(it, link),
+        it.name.as_ref().unwrap(),
+        ty.print()
+    );
+}
+
+fn assoc_type(
+    w: &mut Buffer,
+    it: &clean::Item,
+    bounds: &[clean::GenericBound],
+    default: Option<&clean::Type>,
+    link: AssocItemLink<'_>,
+    extra: &str,
+) {
+    write!(
+        w,
+        "{}type <a href='{}' class=\"type\">{}</a>",
+        extra,
+        naive_assoc_href(it, link),
+        it.name.as_ref().unwrap()
+    );
+    if !bounds.is_empty() {
+        write!(w, ": {}", print_generic_bounds(bounds))
+    }
+    if let Some(default) = default {
+        write!(w, " = {}", default.print())
+    }
+}
+
+fn render_stability_since_raw(w: &mut Buffer, ver: Option<&str>, containing_ver: Option<&str>) {
+    if let Some(v) = ver {
+        if containing_ver != ver && !v.is_empty() {
+            write!(w, "<span class='since' title='Stable since Rust version {0}'>{0}</span>", v)
+        }
+    }
+}
+
+fn render_stability_since(w: &mut Buffer, item: &clean::Item, containing_item: &clean::Item) {
+    render_stability_since_raw(w, item.stable_since(), containing_item.stable_since())
+}
+
+fn render_assoc_item(
+    w: &mut Buffer,
+    item: &clean::Item,
+    link: AssocItemLink<'_>,
+    parent: ItemType,
+) {
+    fn method(
+        w: &mut Buffer,
+        meth: &clean::Item,
+        header: hir::FnHeader,
+        g: &clean::Generics,
+        d: &clean::FnDecl,
+        link: AssocItemLink<'_>,
+        parent: ItemType,
+    ) {
+        let name = meth.name.as_ref().unwrap();
+        let anchor = format!("#{}.{}", meth.type_(), name);
+        let href = match link {
+            AssocItemLink::Anchor(Some(ref id)) => format!("#{}", id),
+            AssocItemLink::Anchor(None) => anchor,
+            AssocItemLink::GotoSource(did, provided_methods) => {
+                // We're creating a link from an impl-item to the corresponding
+                // trait-item and need to map the anchored type accordingly.
+                let ty = if provided_methods.contains(name) {
+                    ItemType::Method
+                } else {
+                    ItemType::TyMethod
+                };
+
+                href(did).map(|p| format!("{}#{}.{}", p.0, ty, name)).unwrap_or(anchor)
+            }
+        };
+        let mut header_len = format!(
+            "{}{}{}{}{}{:#}fn {}{:#}",
+            meth.visibility.print_with_space(),
+            header.constness.print_with_space(),
+            header.asyncness.print_with_space(),
+            header.unsafety.print_with_space(),
+            print_default_space(meth.is_default()),
+            print_abi_with_space(header.abi),
+            name,
+            g.print()
+        )
+        .len();
+        let (indent, end_newline) = if parent == ItemType::Trait {
+            header_len += 4;
+            (4, false)
+        } else {
+            (0, true)
+        };
+        render_attributes(w, meth, false);
+        write!(
+            w,
+            "{}{}{}{}{}{}{}fn <a href='{href}' class='fnname'>{name}</a>\
+                   {generics}{decl}{spotlight}{where_clause}",
+            if parent == ItemType::Trait { "    " } else { "" },
+            meth.visibility.print_with_space(),
+            header.constness.print_with_space(),
+            header.asyncness.print_with_space(),
+            header.unsafety.print_with_space(),
+            print_default_space(meth.is_default()),
+            print_abi_with_space(header.abi),
+            href = href,
+            name = name,
+            generics = g.print(),
+            decl = Function { decl: d, header_len, indent, asyncness: header.asyncness }.print(),
+            spotlight = spotlight_decl(&d),
+            where_clause = WhereClause { gens: g, indent, end_newline }
+        )
+    }
+    match item.inner {
+        clean::StrippedItem(..) => {}
+        clean::TyMethodItem(ref m) => method(w, item, m.header, &m.generics, &m.decl, link, parent),
+        clean::MethodItem(ref m) => method(w, item, m.header, &m.generics, &m.decl, link, parent),
+        clean::AssocConstItem(ref ty, ref default) => assoc_const(
+            w,
+            item,
+            ty,
+            default.as_ref(),
+            link,
+            if parent == ItemType::Trait { "    " } else { "" },
+        ),
+        clean::AssocTypeItem(ref bounds, ref default) => assoc_type(
+            w,
+            item,
+            bounds,
+            default.as_ref(),
+            link,
+            if parent == ItemType::Trait { "    " } else { "" },
+        ),
+        _ => panic!("render_assoc_item called on non-associated-item"),
+    }
+}
+
+fn item_struct(w: &mut Buffer, cx: &Context, it: &clean::Item, s: &clean::Struct, cache: &Cache) {
+    wrap_into_docblock(w, |w| {
+        write!(w, "<pre class='rust struct'>");
+        render_attributes(w, it, true);
+        render_struct(w, it, Some(&s.generics), s.struct_type, &s.fields, "", true);
+        write!(w, "</pre>")
+    });
+
+    document(w, cx, it);
+    let mut fields = s
+        .fields
+        .iter()
+        .filter_map(|f| match f.inner {
+            clean::StructFieldItem(ref ty) => Some((f, ty)),
+            _ => None,
+        })
+        .peekable();
+    if let doctree::Plain = s.struct_type {
+        if fields.peek().is_some() {
+            write!(
+                w,
+                "<h2 id='fields' class='fields small-section-header'>
+                       Fields{}<a href='#fields' class='anchor'></a></h2>",
+                document_non_exhaustive_header(it)
+            );
+            document_non_exhaustive(w, it);
+            for (field, ty) in fields {
+                let id = cx.derive_id(format!(
+                    "{}.{}",
+                    ItemType::StructField,
+                    field.name.as_ref().unwrap()
+                ));
+                write!(
+                    w,
+                    "<span id=\"{id}\" class=\"{item_type} small-section-header\">\
+                           <a href=\"#{id}\" class=\"anchor field\"></a>\
+                           <code>{name}: {ty}</code>\
+                           </span>",
+                    item_type = ItemType::StructField,
+                    id = id,
+                    name = field.name.as_ref().unwrap(),
+                    ty = ty.print()
+                );
+                document(w, cx, field);
+            }
+        }
+    }
+    render_assoc_items(w, cx, it, it.def_id, AssocItemRender::All, cache)
+}
+
+fn item_union(w: &mut Buffer, cx: &Context, it: &clean::Item, s: &clean::Union, cache: &Cache) {
+    wrap_into_docblock(w, |w| {
+        write!(w, "<pre class='rust union'>");
+        render_attributes(w, it, true);
+        render_union(w, it, Some(&s.generics), &s.fields, "", true);
+        write!(w, "</pre>")
+    });
+
+    document(w, cx, it);
+    let mut fields = s
+        .fields
+        .iter()
+        .filter_map(|f| match f.inner {
+            clean::StructFieldItem(ref ty) => Some((f, ty)),
+            _ => None,
+        })
+        .peekable();
+    if fields.peek().is_some() {
+        write!(
+            w,
+            "<h2 id='fields' class='fields small-section-header'>
+                   Fields<a href='#fields' class='anchor'></a></h2>"
+        );
+        for (field, ty) in fields {
+            let name = field.name.as_ref().expect("union field name");
+            let id = format!("{}.{}", ItemType::StructField, name);
+            write!(
+                w,
+                "<span id=\"{id}\" class=\"{shortty} small-section-header\">\
+                           <a href=\"#{id}\" class=\"anchor field\"></a>\
+                           <code>{name}: {ty}</code>\
+                       </span>",
+                id = id,
+                name = name,
+                shortty = ItemType::StructField,
+                ty = ty.print()
+            );
+            if let Some(stability_class) = field.stability_class() {
+                write!(w, "<span class='stab {stab}'></span>", stab = stability_class);
+            }
+            document(w, cx, field);
+        }
+    }
+    render_assoc_items(w, cx, it, it.def_id, AssocItemRender::All, cache)
+}
+
+fn item_enum(w: &mut Buffer, cx: &Context, it: &clean::Item, e: &clean::Enum, cache: &Cache) {
+    wrap_into_docblock(w, |w| {
+        write!(w, "<pre class='rust enum'>");
+        render_attributes(w, it, true);
+        write!(
+            w,
+            "{}enum {}{}{}",
+            it.visibility.print_with_space(),
+            it.name.as_ref().unwrap(),
+            e.generics.print(),
+            WhereClause { gens: &e.generics, indent: 0, end_newline: true }
+        );
+        if e.variants.is_empty() && !e.variants_stripped {
+            write!(w, " {{}}");
+        } else {
+            write!(w, " {{\n");
+            for v in &e.variants {
+                write!(w, "    ");
+                let name = v.name.as_ref().unwrap();
+                match v.inner {
+                    clean::VariantItem(ref var) => match var.kind {
+                        clean::VariantKind::CLike => write!(w, "{}", name),
+                        clean::VariantKind::Tuple(ref tys) => {
+                            write!(w, "{}(", name);
+                            for (i, ty) in tys.iter().enumerate() {
+                                if i > 0 {
+                                    write!(w, ",&nbsp;")
+                                }
+                                write!(w, "{}", ty.print());
+                            }
+                            write!(w, ")");
+                        }
+                        clean::VariantKind::Struct(ref s) => {
+                            render_struct(w, v, None, s.struct_type, &s.fields, "    ", false);
+                        }
+                    },
+                    _ => unreachable!(),
+                }
+                write!(w, ",\n");
+            }
+
+            if e.variants_stripped {
+                write!(w, "    // some variants omitted\n");
+            }
+            write!(w, "}}");
+        }
+        write!(w, "</pre>")
+    });
+
+    document(w, cx, it);
+    if !e.variants.is_empty() {
+        write!(
+            w,
+            "<h2 id='variants' class='variants small-section-header'>
+                   Variants{}<a href='#variants' class='anchor'></a></h2>\n",
+            document_non_exhaustive_header(it)
+        );
+        document_non_exhaustive(w, it);
+        for variant in &e.variants {
+            let id =
+                cx.derive_id(format!("{}.{}", ItemType::Variant, variant.name.as_ref().unwrap()));
+            write!(
+                w,
+                "<div id=\"{id}\" class=\"variant small-section-header\">\
+                    <a href=\"#{id}\" class=\"anchor field\"></a>\
+                    <code>{name}",
+                id = id,
+                name = variant.name.as_ref().unwrap()
+            );
+            if let clean::VariantItem(ref var) = variant.inner {
+                if let clean::VariantKind::Tuple(ref tys) = var.kind {
+                    write!(w, "(");
+                    for (i, ty) in tys.iter().enumerate() {
+                        if i > 0 {
+                            write!(w, ",&nbsp;");
+                        }
+                        write!(w, "{}", ty.print());
+                    }
+                    write!(w, ")");
+                }
+            }
+            write!(w, "</code></div>");
+            document(w, cx, variant);
+            document_non_exhaustive(w, variant);
+
+            use crate::clean::{Variant, VariantKind};
+            if let clean::VariantItem(Variant { kind: VariantKind::Struct(ref s) }) = variant.inner
+            {
+                let variant_id = cx.derive_id(format!(
+                    "{}.{}.fields",
+                    ItemType::Variant,
+                    variant.name.as_ref().unwrap()
+                ));
+                write!(w, "<div class='autohide sub-variant' id='{id}'>", id = variant_id);
+                write!(
+                    w,
+                    "<h3>Fields of <b>{name}</b></h3><div>",
+                    name = variant.name.as_ref().unwrap()
+                );
+                for field in &s.fields {
+                    use crate::clean::StructFieldItem;
+                    if let StructFieldItem(ref ty) = field.inner {
+                        let id = cx.derive_id(format!(
+                            "variant.{}.field.{}",
+                            variant.name.as_ref().unwrap(),
+                            field.name.as_ref().unwrap()
+                        ));
+                        write!(
+                            w,
+                            "<span id=\"{id}\" class=\"variant small-section-header\">\
+                                   <a href=\"#{id}\" class=\"anchor field\"></a>\
+                                   <code>{f}:&nbsp;{t}\
+                                   </code></span>",
+                            id = id,
+                            f = field.name.as_ref().unwrap(),
+                            t = ty.print()
+                        );
+                        document(w, cx, field);
+                    }
+                }
+                write!(w, "</div></div>");
+            }
+            render_stability_since(w, variant, it);
+        }
+    }
+    render_assoc_items(w, cx, it, it.def_id, AssocItemRender::All, cache)
+}
+
+const ALLOWED_ATTRIBUTES: &[Symbol] = &[
+    sym::export_name,
+    sym::lang,
+    sym::link_section,
+    sym::must_use,
+    sym::no_mangle,
+    sym::repr,
+    sym::non_exhaustive,
+];
+
+// The `top` parameter is used when generating the item declaration to ensure it doesn't have a
+// left padding. For example:
+//
+// #[foo] <----- "top" attribute
+// struct Foo {
+//     #[bar] <---- not "top" attribute
+//     bar: usize,
+// }
+fn render_attributes(w: &mut Buffer, it: &clean::Item, top: bool) {
+    let attrs = it
+        .attrs
+        .other_attrs
+        .iter()
+        .filter_map(|attr| {
+            if ALLOWED_ATTRIBUTES.contains(&attr.name_or_empty()) {
+                Some(pprust::attribute_to_string(&attr))
+            } else {
+                None
+            }
+        })
+        .join("\n");
+
+    if !attrs.is_empty() {
+        write!(
+            w,
+            "<span class=\"docblock attributes{}\">{}</span>",
+            if top { " top-attr" } else { "" },
+            &attrs
+        );
+    }
+}
+
+fn render_struct(
+    w: &mut Buffer,
+    it: &clean::Item,
+    g: Option<&clean::Generics>,
+    ty: doctree::StructType,
+    fields: &[clean::Item],
+    tab: &str,
+    structhead: bool,
+) {
+    write!(
+        w,
+        "{}{}{}",
+        it.visibility.print_with_space(),
+        if structhead { "struct " } else { "" },
+        it.name.as_ref().unwrap()
+    );
+    if let Some(g) = g {
+        write!(w, "{}", g.print())
+    }
+    match ty {
+        doctree::Plain => {
+            if let Some(g) = g {
+                write!(w, "{}", WhereClause { gens: g, indent: 0, end_newline: true })
+            }
+            let mut has_visible_fields = false;
+            write!(w, " {{");
+            for field in fields {
+                if let clean::StructFieldItem(ref ty) = field.inner {
+                    write!(
+                        w,
+                        "\n{}    {}{}: {},",
+                        tab,
+                        field.visibility.print_with_space(),
+                        field.name.as_ref().unwrap(),
+                        ty.print()
+                    );
+                    has_visible_fields = true;
+                }
+            }
+
+            if has_visible_fields {
+                if it.has_stripped_fields().unwrap() {
+                    write!(w, "\n{}    // some fields omitted", tab);
+                }
+                write!(w, "\n{}", tab);
+            } else if it.has_stripped_fields().unwrap() {
+                // If there are no visible fields we can just display
+                // `{ /* fields omitted */ }` to save space.
+                write!(w, " /* fields omitted */ ");
+            }
+            write!(w, "}}");
+        }
+        doctree::Tuple => {
+            write!(w, "(");
+            for (i, field) in fields.iter().enumerate() {
+                if i > 0 {
+                    write!(w, ", ");
+                }
+                match field.inner {
+                    clean::StrippedItem(box clean::StructFieldItem(..)) => write!(w, "_"),
+                    clean::StructFieldItem(ref ty) => {
+                        write!(w, "{}{}", field.visibility.print_with_space(), ty.print())
+                    }
+                    _ => unreachable!(),
+                }
+            }
+            write!(w, ")");
+            if let Some(g) = g {
+                write!(w, "{}", WhereClause { gens: g, indent: 0, end_newline: false })
+            }
+            write!(w, ";");
+        }
+        doctree::Unit => {
+            // Needed for PhantomData.
+            if let Some(g) = g {
+                write!(w, "{}", WhereClause { gens: g, indent: 0, end_newline: false })
+            }
+            write!(w, ";");
+        }
+    }
+}
+
+fn render_union(
+    w: &mut Buffer,
+    it: &clean::Item,
+    g: Option<&clean::Generics>,
+    fields: &[clean::Item],
+    tab: &str,
+    structhead: bool,
+) {
+    write!(
+        w,
+        "{}{}{}",
+        it.visibility.print_with_space(),
+        if structhead { "union " } else { "" },
+        it.name.as_ref().unwrap()
+    );
+    if let Some(g) = g {
+        write!(w, "{}", g.print());
+        write!(w, "{}", WhereClause { gens: g, indent: 0, end_newline: true });
+    }
+
+    write!(w, " {{\n{}", tab);
+    for field in fields {
+        if let clean::StructFieldItem(ref ty) = field.inner {
+            write!(
+                w,
+                "    {}{}: {},\n{}",
+                field.visibility.print_with_space(),
+                field.name.as_ref().unwrap(),
+                ty.print(),
+                tab
+            );
+        }
+    }
+
+    if it.has_stripped_fields().unwrap() {
+        write!(w, "    // some fields omitted\n{}", tab);
+    }
+    write!(w, "}}");
+}
+
+#[derive(Copy, Clone)]
+enum AssocItemLink<'a> {
+    Anchor(Option<&'a str>),
+    GotoSource(DefId, &'a FxHashSet<String>),
+}
+
+impl<'a> AssocItemLink<'a> {
+    fn anchor(&self, id: &'a String) -> Self {
+        match *self {
+            AssocItemLink::Anchor(_) => AssocItemLink::Anchor(Some(&id)),
+            ref other => *other,
+        }
+    }
+}
+
+fn render_assoc_items(
+    w: &mut Buffer,
+    cx: &Context,
+    containing_item: &clean::Item,
+    it: DefId,
+    what: AssocItemRender<'_>,
+    cache: &Cache,
+) {
+    let v = match cache.impls.get(&it) {
+        Some(v) => v,
+        None => return,
+    };
+    let (non_trait, traits): (Vec<_>, _) = v.iter().partition(|i| i.inner_impl().trait_.is_none());
+    if !non_trait.is_empty() {
+        let render_mode = match what {
+            AssocItemRender::All => {
+                write!(
+                    w,
+                    "\
+                    <h2 id='implementations' class='small-section-header'>\
+                      Implementations<a href='#implementations' class='anchor'></a>\
+                    </h2>\
+                "
+                );
+                RenderMode::Normal
+            }
+            AssocItemRender::DerefFor { trait_, type_, deref_mut_ } => {
+                write!(
+                    w,
+                    "\
+                    <h2 id='deref-methods' class='small-section-header'>\
+                      Methods from {}&lt;Target = {}&gt;\
+                      <a href='#deref-methods' class='anchor'></a>\
+                    </h2>\
+                ",
+                    trait_.print(),
+                    type_.print()
+                );
+                RenderMode::ForDeref { mut_: deref_mut_ }
+            }
+        };
+        for i in &non_trait {
+            render_impl(
+                w,
+                cx,
+                i,
+                AssocItemLink::Anchor(None),
+                render_mode,
+                containing_item.stable_since(),
+                true,
+                None,
+                false,
+                true,
+                &[],
+                cache,
+            );
+        }
+    }
+    if let AssocItemRender::DerefFor { .. } = what {
+        return;
+    }
+    if !traits.is_empty() {
+        let deref_impl =
+            traits.iter().find(|t| t.inner_impl().trait_.def_id() == cache.deref_trait_did);
+        if let Some(impl_) = deref_impl {
+            let has_deref_mut =
+                traits.iter().any(|t| t.inner_impl().trait_.def_id() == cache.deref_mut_trait_did);
+            render_deref_methods(w, cx, impl_, containing_item, has_deref_mut, cache);
+        }
+
+        let (synthetic, concrete): (Vec<&&Impl>, Vec<&&Impl>) =
+            traits.iter().partition(|t| t.inner_impl().synthetic);
+        let (blanket_impl, concrete): (Vec<&&Impl>, _) =
+            concrete.into_iter().partition(|t| t.inner_impl().blanket_impl.is_some());
+
+        let mut impls = Buffer::empty_from(&w);
+        render_impls(cx, &mut impls, &concrete, containing_item, cache);
+        let impls = impls.into_inner();
+        if !impls.is_empty() {
+            write!(
+                w,
+                "\
+                <h2 id='trait-implementations' class='small-section-header'>\
+                  Trait Implementations<a href='#trait-implementations' class='anchor'></a>\
+                </h2>\
+                <div id='trait-implementations-list'>{}</div>",
+                impls
+            );
+        }
+
+        if !synthetic.is_empty() {
+            write!(
+                w,
+                "\
+                <h2 id='synthetic-implementations' class='small-section-header'>\
+                  Auto Trait Implementations\
+                  <a href='#synthetic-implementations' class='anchor'></a>\
+                </h2>\
+                <div id='synthetic-implementations-list'>\
+            "
+            );
+            render_impls(cx, w, &synthetic, containing_item, cache);
+            write!(w, "</div>");
+        }
+
+        if !blanket_impl.is_empty() {
+            write!(
+                w,
+                "\
+                <h2 id='blanket-implementations' class='small-section-header'>\
+                  Blanket Implementations\
+                  <a href='#blanket-implementations' class='anchor'></a>\
+                </h2>\
+                <div id='blanket-implementations-list'>\
+            "
+            );
+            render_impls(cx, w, &blanket_impl, containing_item, cache);
+            write!(w, "</div>");
+        }
+    }
+}
+
+fn render_deref_methods(
+    w: &mut Buffer,
+    cx: &Context,
+    impl_: &Impl,
+    container_item: &clean::Item,
+    deref_mut: bool,
+    cache: &Cache,
+) {
+    let deref_type = impl_.inner_impl().trait_.as_ref().unwrap();
+    let (target, real_target) = impl_
+        .inner_impl()
+        .items
+        .iter()
+        .find_map(|item| match item.inner {
+            clean::TypedefItem(ref t, true) => Some(match *t {
+                clean::Typedef { item_type: Some(ref type_), .. } => (type_, &t.type_),
+                _ => (&t.type_, &t.type_),
+            }),
+            _ => None,
+        })
+        .expect("Expected associated type binding");
+    let what =
+        AssocItemRender::DerefFor { trait_: deref_type, type_: real_target, deref_mut_: deref_mut };
+    if let Some(did) = target.def_id() {
+        render_assoc_items(w, cx, container_item, did, what, cache);
+    } else {
+        if let Some(prim) = target.primitive_type() {
+            if let Some(&did) = cache.primitive_locations.get(&prim) {
+                render_assoc_items(w, cx, container_item, did, what, cache);
+            }
+        }
+    }
+}
+
+fn should_render_item(item: &clean::Item, deref_mut_: bool) -> bool {
+    let self_type_opt = match item.inner {
+        clean::MethodItem(ref method) => method.decl.self_type(),
+        clean::TyMethodItem(ref method) => method.decl.self_type(),
+        _ => None,
+    };
+
+    if let Some(self_ty) = self_type_opt {
+        let (by_mut_ref, by_box, by_value) = match self_ty {
+            SelfTy::SelfBorrowed(_, mutability)
+            | SelfTy::SelfExplicit(clean::BorrowedRef { mutability, .. }) => {
+                (mutability == Mutability::Mut, false, false)
+            }
+            SelfTy::SelfExplicit(clean::ResolvedPath { did, .. }) => {
+                (false, Some(did) == cache().owned_box_did, false)
+            }
+            SelfTy::SelfValue => (false, false, true),
+            _ => (false, false, false),
+        };
+
+        (deref_mut_ || !by_mut_ref) && !by_box && !by_value
+    } else {
+        false
+    }
+}
+
+fn spotlight_decl(decl: &clean::FnDecl) -> String {
+    let mut out = Buffer::html();
+    let mut trait_ = String::new();
+
+    if let Some(did) = decl.output.def_id() {
+        let c = cache();
+        if let Some(impls) = c.impls.get(&did) {
+            for i in impls {
+                let impl_ = i.inner_impl();
+                if impl_.trait_.def_id().map_or(false, |d| c.traits[&d].is_spotlight) {
+                    if out.is_empty() {
+                        out.push_str(&format!(
+                            "<h3 class=\"important\">Important traits for {}</h3>\
+                                      <code class=\"content\">",
+                            impl_.for_.print()
+                        ));
+                        trait_.push_str(&impl_.for_.print().to_string());
+                    }
+
+                    //use the "where" class here to make it small
+                    out.push_str(&format!(
+                        "<span class=\"where fmt-newline\">{}</span>",
+                        impl_.print()
+                    ));
+                    let t_did = impl_.trait_.def_id().unwrap();
+                    for it in &impl_.items {
+                        if let clean::TypedefItem(ref tydef, _) = it.inner {
+                            out.push_str("<span class=\"where fmt-newline\">    ");
+                            assoc_type(
+                                &mut out,
+                                it,
+                                &[],
+                                Some(&tydef.type_),
+                                AssocItemLink::GotoSource(t_did, &FxHashSet::default()),
+                                "",
+                            );
+                            out.push_str(";</span>");
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    if !out.is_empty() {
+        out.insert_str(
+            0,
+            "<span class=\"important-traits\"><span class=\"important-traits-tooltip\">ⓘ<div class='important-traits-tooltiptext'><span class=\"docblock\">"
+
+        );
+        out.push_str("</code></span></div></span></span>");
+    }
+
+    out.into_inner()
+}
+
+fn render_impl(
+    w: &mut Buffer,
+    cx: &Context,
+    i: &Impl,
+    link: AssocItemLink<'_>,
+    render_mode: RenderMode,
+    outer_version: Option<&str>,
+    show_def_docs: bool,
+    use_absolute: Option<bool>,
+    is_on_foreign_type: bool,
+    show_default_items: bool,
+    // This argument is used to reference same type with different paths to avoid duplication
+    // in documentation pages for trait with automatic implementations like "Send" and "Sync".
+    aliases: &[String],
+    cache: &Cache,
+) {
+    if render_mode == RenderMode::Normal {
+        let id = cx.derive_id(match i.inner_impl().trait_ {
+            Some(ref t) => {
+                if is_on_foreign_type {
+                    get_id_for_impl_on_foreign_type(&i.inner_impl().for_, t)
+                } else {
+                    format!("impl-{}", small_url_encode(&format!("{:#}", t.print())))
+                }
+            }
+            None => "impl".to_string(),
+        });
+        let aliases = if aliases.is_empty() {
+            String::new()
+        } else {
+            format!(" aliases=\"{}\"", aliases.join(","))
+        };
+        if let Some(use_absolute) = use_absolute {
+            write!(w, "<h3 id='{}' class='impl'{}><code class='in-band'>", id, aliases);
+            fmt_impl_for_trait_page(&i.inner_impl(), w, use_absolute);
+            if show_def_docs {
+                for it in &i.inner_impl().items {
+                    if let clean::TypedefItem(ref tydef, _) = it.inner {
+                        write!(w, "<span class=\"where fmt-newline\">  ");
+                        assoc_type(w, it, &[], Some(&tydef.type_), AssocItemLink::Anchor(None), "");
+                        write!(w, ";</span>");
+                    }
+                }
+            }
+            write!(w, "</code>");
+        } else {
+            write!(
+                w,
+                "<h3 id='{}' class='impl'{}><code class='in-band'>{}</code>",
+                id,
+                aliases,
+                i.inner_impl().print()
+            );
+        }
+        write!(w, "<a href='#{}' class='anchor'></a>", id);
+        let since = i.impl_item.stability.as_ref().map(|s| &s.since[..]);
+        render_stability_since_raw(w, since, outer_version);
+        if let Some(l) = cx.src_href(&i.impl_item, cache) {
+            write!(w, "<a class='srclink' href='{}' title='{}'>[src]</a>", l, "goto source code");
+        }
+        write!(w, "</h3>");
+        if let Some(ref dox) = cx.shared.maybe_collapsed_doc_value(&i.impl_item) {
+            let mut ids = cx.id_map.borrow_mut();
+            write!(
+                w,
+                "<div class='docblock'>{}</div>",
+                Markdown(
+                    &*dox,
+                    &i.impl_item.links(),
+                    &mut ids,
+                    cx.shared.codes,
+                    cx.shared.edition,
+                    &cx.shared.playground
+                )
+                .into_string()
+            );
+        }
+    }
+
+    fn doc_impl_item(
+        w: &mut Buffer,
+        cx: &Context,
+        item: &clean::Item,
+        link: AssocItemLink<'_>,
+        render_mode: RenderMode,
+        is_default_item: bool,
+        outer_version: Option<&str>,
+        trait_: Option<&clean::Trait>,
+        show_def_docs: bool,
+        cache: &Cache,
+    ) {
+        let item_type = item.type_();
+        let name = item.name.as_ref().unwrap();
+
+        let render_method_item = match render_mode {
+            RenderMode::Normal => true,
+            RenderMode::ForDeref { mut_: deref_mut_ } => should_render_item(&item, deref_mut_),
+        };
+
+        let (is_hidden, extra_class) =
+            if (trait_.is_none() || item.doc_value().is_some() || item.inner.is_associated())
+                && !is_default_item
+            {
+                (false, "")
+            } else {
+                (true, " hidden")
+            };
+        match item.inner {
+            clean::MethodItem(clean::Method { .. })
+            | clean::TyMethodItem(clean::TyMethod { .. }) => {
+                // Only render when the method is not static or we allow static methods
+                if render_method_item {
+                    let id = cx.derive_id(format!("{}.{}", item_type, name));
+                    write!(w, "<h4 id='{}' class=\"{}{}\">", id, item_type, extra_class);
+                    write!(w, "<code>");
+                    render_assoc_item(w, item, link.anchor(&id), ItemType::Impl);
+                    write!(w, "</code>");
+                    render_stability_since_raw(w, item.stable_since(), outer_version);
+                    if let Some(l) = cx.src_href(item, cache) {
+                        write!(
+                            w,
+                            "<a class='srclink' href='{}' title='{}'>[src]</a>",
+                            l, "goto source code"
+                        );
+                    }
+                    write!(w, "</h4>");
+                }
+            }
+            clean::TypedefItem(ref tydef, _) => {
+                let id = cx.derive_id(format!("{}.{}", ItemType::AssocType, name));
+                write!(w, "<h4 id='{}' class=\"{}{}\"><code>", id, item_type, extra_class);
+                assoc_type(w, item, &Vec::new(), Some(&tydef.type_), link.anchor(&id), "");
+                write!(w, "</code></h4>");
+            }
+            clean::AssocConstItem(ref ty, ref default) => {
+                let id = cx.derive_id(format!("{}.{}", item_type, name));
+                write!(w, "<h4 id='{}' class=\"{}{}\"><code>", id, item_type, extra_class);
+                assoc_const(w, item, ty, default.as_ref(), link.anchor(&id), "");
+                write!(w, "</code>");
+                render_stability_since_raw(w, item.stable_since(), outer_version);
+                if let Some(l) = cx.src_href(item, cache) {
+                    write!(
+                        w,
+                        "<a class='srclink' href='{}' title='{}'>[src]</a>",
+                        l, "goto source code"
+                    );
+                }
+                write!(w, "</h4>");
+            }
+            clean::AssocTypeItem(ref bounds, ref default) => {
+                let id = cx.derive_id(format!("{}.{}", item_type, name));
+                write!(w, "<h4 id='{}' class=\"{}{}\"><code>", id, item_type, extra_class);
+                assoc_type(w, item, bounds, default.as_ref(), link.anchor(&id), "");
+                write!(w, "</code></h4>");
+            }
+            clean::StrippedItem(..) => return,
+            _ => panic!("can't make docs for trait item with name {:?}", item.name),
+        }
+
+        if render_method_item {
+            if !is_default_item {
+                if let Some(t) = trait_ {
+                    // The trait item may have been stripped so we might not
+                    // find any documentation or stability for it.
+                    if let Some(it) = t.items.iter().find(|i| i.name == item.name) {
+                        // We need the stability of the item from the trait
+                        // because impls can't have a stability.
+                        document_stability(w, cx, it, is_hidden);
+                        if item.doc_value().is_some() {
+                            document_full(w, item, cx, "", is_hidden);
+                        } else if show_def_docs {
+                            // In case the item isn't documented,
+                            // provide short documentation from the trait.
+                            document_short(w, cx, it, link, "", is_hidden);
+                        }
+                    }
+                } else {
+                    document_stability(w, cx, item, is_hidden);
+                    if show_def_docs {
+                        document_full(w, item, cx, "", is_hidden);
+                    }
+                }
+            } else {
+                document_stability(w, cx, item, is_hidden);
+                if show_def_docs {
+                    document_short(w, cx, item, link, "", is_hidden);
+                }
+            }
+        }
+    }
+
+    let traits = &cache.traits;
+    let trait_ = i.trait_did().map(|did| &traits[&did]);
+
+    write!(w, "<div class='impl-items'>");
+    for trait_item in &i.inner_impl().items {
+        doc_impl_item(
+            w,
+            cx,
+            trait_item,
+            link,
+            render_mode,
+            false,
+            outer_version,
+            trait_,
+            show_def_docs,
+            cache,
+        );
+    }
+
+    fn render_default_items(
+        w: &mut Buffer,
+        cx: &Context,
+        t: &clean::Trait,
+        i: &clean::Impl,
+        render_mode: RenderMode,
+        outer_version: Option<&str>,
+        show_def_docs: bool,
+        cache: &Cache,
+    ) {
+        for trait_item in &t.items {
+            let n = trait_item.name.clone();
+            if i.items.iter().any(|m| m.name == n) {
+                continue;
+            }
+            let did = i.trait_.as_ref().unwrap().def_id().unwrap();
+            let assoc_link = AssocItemLink::GotoSource(did, &i.provided_trait_methods);
+
+            doc_impl_item(
+                w,
+                cx,
+                trait_item,
+                assoc_link,
+                render_mode,
+                true,
+                outer_version,
+                None,
+                show_def_docs,
+                cache,
+            );
+        }
+    }
+
+    // If we've implemented a trait, then also emit documentation for all
+    // default items which weren't overridden in the implementation block.
+    // We don't emit documentation for default items if they appear in the
+    // Implementations on Foreign Types or Implementors sections.
+    if show_default_items {
+        if let Some(t) = trait_ {
+            render_default_items(
+                w,
+                cx,
+                t,
+                &i.inner_impl(),
+                render_mode,
+                outer_version,
+                show_def_docs,
+                cache,
+            );
+        }
+    }
+    write!(w, "</div>");
+}
+
+fn item_opaque_ty(
+    w: &mut Buffer,
+    cx: &Context,
+    it: &clean::Item,
+    t: &clean::OpaqueTy,
+    cache: &Cache,
+) {
+    write!(w, "<pre class='rust opaque'>");
+    render_attributes(w, it, false);
+    write!(
+        w,
+        "type {}{}{where_clause} = impl {bounds};</pre>",
+        it.name.as_ref().unwrap(),
+        t.generics.print(),
+        where_clause = WhereClause { gens: &t.generics, indent: 0, end_newline: true },
+        bounds = bounds(&t.bounds, false)
+    );
+
+    document(w, cx, it);
+
+    // Render any items associated directly to this alias, as otherwise they
+    // won't be visible anywhere in the docs. It would be nice to also show
+    // associated items from the aliased type (see discussion in #32077), but
+    // we need #14072 to make sense of the generics.
+    render_assoc_items(w, cx, it, it.def_id, AssocItemRender::All, cache)
+}
+
+fn item_trait_alias(
+    w: &mut Buffer,
+    cx: &Context,
+    it: &clean::Item,
+    t: &clean::TraitAlias,
+    cache: &Cache,
+) {
+    write!(w, "<pre class='rust trait-alias'>");
+    render_attributes(w, it, false);
+    write!(
+        w,
+        "trait {}{}{} = {};</pre>",
+        it.name.as_ref().unwrap(),
+        t.generics.print(),
+        WhereClause { gens: &t.generics, indent: 0, end_newline: true },
+        bounds(&t.bounds, true)
+    );
+
+    document(w, cx, it);
+
+    // Render any items associated directly to this alias, as otherwise they
+    // won't be visible anywhere in the docs. It would be nice to also show
+    // associated items from the aliased type (see discussion in #32077), but
+    // we need #14072 to make sense of the generics.
+    render_assoc_items(w, cx, it, it.def_id, AssocItemRender::All, cache)
+}
+
+fn item_typedef(w: &mut Buffer, cx: &Context, it: &clean::Item, t: &clean::Typedef, cache: &Cache) {
+    write!(w, "<pre class='rust typedef'>");
+    render_attributes(w, it, false);
+    write!(
+        w,
+        "type {}{}{where_clause} = {type_};</pre>",
+        it.name.as_ref().unwrap(),
+        t.generics.print(),
+        where_clause = WhereClause { gens: &t.generics, indent: 0, end_newline: true },
+        type_ = t.type_.print()
+    );
+
+    document(w, cx, it);
+
+    // Render any items associated directly to this alias, as otherwise they
+    // won't be visible anywhere in the docs. It would be nice to also show
+    // associated items from the aliased type (see discussion in #32077), but
+    // we need #14072 to make sense of the generics.
+    render_assoc_items(w, cx, it, it.def_id, AssocItemRender::All, cache)
+}
+
+fn item_foreign_type(w: &mut Buffer, cx: &Context, it: &clean::Item, cache: &Cache) {
+    writeln!(w, "<pre class='rust foreigntype'>extern {{");
+    render_attributes(w, it, false);
+    write!(
+        w,
+        "    {}type {};\n}}</pre>",
+        it.visibility.print_with_space(),
+        it.name.as_ref().unwrap(),
+    );
+
+    document(w, cx, it);
+
+    render_assoc_items(w, cx, it, it.def_id, AssocItemRender::All, cache)
+}
+
+fn print_sidebar(cx: &Context, it: &clean::Item, buffer: &mut Buffer, cache: &Cache) {
+    let parentlen = cx.current.len() - if it.is_mod() { 1 } else { 0 };
+
+    if it.is_struct()
+        || it.is_trait()
+        || it.is_primitive()
+        || it.is_union()
+        || it.is_enum()
+        || it.is_mod()
+        || it.is_typedef()
+    {
+        write!(
+            buffer,
+            "<p class='location'>{}{}</p>",
+            match it.inner {
+                clean::StructItem(..) => "Struct ",
+                clean::TraitItem(..) => "Trait ",
+                clean::PrimitiveItem(..) => "Primitive Type ",
+                clean::UnionItem(..) => "Union ",
+                clean::EnumItem(..) => "Enum ",
+                clean::TypedefItem(..) => "Type Definition ",
+                clean::ForeignTypeItem => "Foreign Type ",
+                clean::ModuleItem(..) =>
+                    if it.is_crate() {
+                        "Crate "
+                    } else {
+                        "Module "
+                    },
+                _ => "",
+            },
+            it.name.as_ref().unwrap()
+        );
+    }
+
+    if it.is_crate() {
+        if let Some(ref version) = cache.crate_version {
+            write!(
+                buffer,
+                "<div class='block version'>\
+                    <p>Version {}</p>\
+                    </div>",
+                Escape(version)
+            );
+        }
+    }
+
+    write!(buffer, "<div class=\"sidebar-elems\">");
+    if it.is_crate() {
+        write!(
+            buffer,
+            "<a id='all-types' href='all.html'><p>See all {}'s items</p></a>",
+            it.name.as_ref().expect("crates always have a name")
+        );
+    }
+    match it.inner {
+        clean::StructItem(ref s) => sidebar_struct(buffer, it, s),
+        clean::TraitItem(ref t) => sidebar_trait(buffer, it, t),
+        clean::PrimitiveItem(_) => sidebar_primitive(buffer, it),
+        clean::UnionItem(ref u) => sidebar_union(buffer, it, u),
+        clean::EnumItem(ref e) => sidebar_enum(buffer, it, e),
+        clean::TypedefItem(_, _) => sidebar_typedef(buffer, it),
+        clean::ModuleItem(ref m) => sidebar_module(buffer, &m.items),
+        clean::ForeignTypeItem => sidebar_foreign_type(buffer, it),
+        _ => (),
+    }
+
+    // The sidebar is designed to display sibling functions, modules and
+    // other miscellaneous information. since there are lots of sibling
+    // items (and that causes quadratic growth in large modules),
+    // we refactor common parts into a shared JavaScript file per module.
+    // still, we don't move everything into JS because we want to preserve
+    // as much HTML as possible in order to allow non-JS-enabled browsers
+    // to navigate the documentation (though slightly inefficiently).
+
+    write!(buffer, "<p class='location'>");
+    for (i, name) in cx.current.iter().take(parentlen).enumerate() {
+        if i > 0 {
+            write!(buffer, "::<wbr>");
+        }
+        write!(
+            buffer,
+            "<a href='{}index.html'>{}</a>",
+            &cx.root_path()[..(cx.current.len() - i - 1) * 3],
+            *name
+        );
+    }
+    write!(buffer, "</p>");
+
+    // Sidebar refers to the enclosing module, not this module.
+    let relpath = if it.is_mod() { "../" } else { "" };
+    write!(
+        buffer,
+        "<script>window.sidebarCurrent = {{\
+                name: '{name}', \
+                ty: '{ty}', \
+                relpath: '{path}'\
+            }};</script>",
+        name = it.name.as_ref().map(|x| &x[..]).unwrap_or(""),
+        ty = it.type_(),
+        path = relpath
+    );
+    if parentlen == 0 {
+        // There is no sidebar-items.js beyond the crate root path
+        // FIXME maybe dynamic crate loading can be merged here
+    } else {
+        write!(buffer, "<script defer src=\"{path}sidebar-items.js\"></script>", path = relpath);
+    }
+    // Closes sidebar-elems div.
+    write!(buffer, "</div>");
+}
+
+fn get_next_url(used_links: &mut FxHashSet<String>, url: String) -> String {
+    if used_links.insert(url.clone()) {
+        return url;
+    }
+    let mut add = 1;
+    while !used_links.insert(format!("{}-{}", url, add)) {
+        add += 1;
+    }
+    format!("{}-{}", url, add)
+}
+
+fn get_methods(
+    i: &clean::Impl,
+    for_deref: bool,
+    used_links: &mut FxHashSet<String>,
+    deref_mut: bool,
+) -> Vec<String> {
+    i.items
+        .iter()
+        .filter_map(|item| match item.name {
+            Some(ref name) if !name.is_empty() && item.is_method() => {
+                if !for_deref || should_render_item(item, deref_mut) {
+                    Some(format!(
+                        "<a href=\"#{}\">{}</a>",
+                        get_next_url(used_links, format!("method.{}", name)),
+                        name
+                    ))
+                } else {
+                    None
+                }
+            }
+            _ => None,
+        })
+        .collect::<Vec<_>>()
+}
+
+// The point is to url encode any potential character from a type with genericity.
+fn small_url_encode(s: &str) -> String {
+    s.replace("<", "%3C")
+        .replace(">", "%3E")
+        .replace(" ", "%20")
+        .replace("?", "%3F")
+        .replace("'", "%27")
+        .replace("&", "%26")
+        .replace(",", "%2C")
+        .replace(":", "%3A")
+        .replace(";", "%3B")
+        .replace("[", "%5B")
+        .replace("]", "%5D")
+        .replace("\"", "%22")
+}
+
+fn sidebar_assoc_items(it: &clean::Item) -> String {
+    let mut out = String::new();
+    let c = cache();
+    if let Some(v) = c.impls.get(&it.def_id) {
+        let mut used_links = FxHashSet::default();
+
+        {
+            let used_links_bor = &mut used_links;
+            let mut ret = v
+                .iter()
+                .filter(|i| i.inner_impl().trait_.is_none())
+                .flat_map(move |i| get_methods(i.inner_impl(), false, used_links_bor, false))
+                .collect::<Vec<_>>();
+            if !ret.is_empty() {
+                // We want links' order to be reproducible so we don't use unstable sort.
+                ret.sort();
+                out.push_str(&format!(
+                    "<a class=\"sidebar-title\" href=\"#implementations\">Methods</a>\
+                     <div class=\"sidebar-links\">{}</div>",
+                    ret.join("")
+                ));
+            }
+        }
+
+        if v.iter().any(|i| i.inner_impl().trait_.is_some()) {
+            if let Some(impl_) = v
+                .iter()
+                .filter(|i| i.inner_impl().trait_.is_some())
+                .find(|i| i.inner_impl().trait_.def_id() == c.deref_trait_did)
+            {
+                if let Some((target, real_target)) =
+                    impl_.inner_impl().items.iter().find_map(|item| match item.inner {
+                        clean::TypedefItem(ref t, true) => Some(match *t {
+                            clean::Typedef { item_type: Some(ref type_), .. } => (type_, &t.type_),
+                            _ => (&t.type_, &t.type_),
+                        }),
+                        _ => None,
+                    })
+                {
+                    let deref_mut = v
+                        .iter()
+                        .filter(|i| i.inner_impl().trait_.is_some())
+                        .any(|i| i.inner_impl().trait_.def_id() == c.deref_mut_trait_did);
+                    let inner_impl = target
+                        .def_id()
+                        .or(target
+                            .primitive_type()
+                            .and_then(|prim| c.primitive_locations.get(&prim).cloned()))
+                        .and_then(|did| c.impls.get(&did));
+                    if let Some(impls) = inner_impl {
+                        out.push_str("<a class=\"sidebar-title\" href=\"#deref-methods\">");
+                        out.push_str(&format!(
+                            "Methods from {}&lt;Target={}&gt;",
+                            Escape(&format!(
+                                "{:#}",
+                                impl_.inner_impl().trait_.as_ref().unwrap().print()
+                            )),
+                            Escape(&format!("{:#}", real_target.print()))
+                        ));
+                        out.push_str("</a>");
+                        let mut ret = impls
+                            .iter()
+                            .filter(|i| i.inner_impl().trait_.is_none())
+                            .flat_map(|i| {
+                                get_methods(i.inner_impl(), true, &mut used_links, deref_mut)
+                            })
+                            .collect::<Vec<_>>();
+                        // We want links' order to be reproducible so we don't use unstable sort.
+                        ret.sort();
+                        if !ret.is_empty() {
+                            out.push_str(&format!(
+                                "<div class=\"sidebar-links\">{}</div>",
+                                ret.join("")
+                            ));
+                        }
+                    }
+                }
+            }
+            let format_impls = |impls: Vec<&Impl>| {
+                let mut links = FxHashSet::default();
+
+                let mut ret = impls
+                    .iter()
+                    .filter_map(|i| {
+                        let is_negative_impl = is_negative_impl(i.inner_impl());
+                        if let Some(ref i) = i.inner_impl().trait_ {
+                            let i_display = format!("{:#}", i.print());
+                            let out = Escape(&i_display);
+                            let encoded = small_url_encode(&format!("{:#}", i.print()));
+                            let generated = format!(
+                                "<a href=\"#impl-{}\">{}{}</a>",
+                                encoded,
+                                if is_negative_impl { "!" } else { "" },
+                                out
+                            );
+                            if links.insert(generated.clone()) { Some(generated) } else { None }
+                        } else {
+                            None
+                        }
+                    })
+                    .collect::<Vec<String>>();
+                ret.sort();
+                ret.join("")
+            };
+
+            let (synthetic, concrete): (Vec<&Impl>, Vec<&Impl>) =
+                v.iter().partition::<Vec<_>, _>(|i| i.inner_impl().synthetic);
+            let (blanket_impl, concrete): (Vec<&Impl>, Vec<&Impl>) = concrete
+                .into_iter()
+                .partition::<Vec<_>, _>(|i| i.inner_impl().blanket_impl.is_some());
+
+            let concrete_format = format_impls(concrete);
+            let synthetic_format = format_impls(synthetic);
+            let blanket_format = format_impls(blanket_impl);
+
+            if !concrete_format.is_empty() {
+                out.push_str(
+                    "<a class=\"sidebar-title\" href=\"#trait-implementations\">\
+                        Trait Implementations</a>",
+                );
+                out.push_str(&format!("<div class=\"sidebar-links\">{}</div>", concrete_format));
+            }
+
+            if !synthetic_format.is_empty() {
+                out.push_str(
+                    "<a class=\"sidebar-title\" href=\"#synthetic-implementations\">\
+                        Auto Trait Implementations</a>",
+                );
+                out.push_str(&format!("<div class=\"sidebar-links\">{}</div>", synthetic_format));
+            }
+
+            if !blanket_format.is_empty() {
+                out.push_str(
+                    "<a class=\"sidebar-title\" href=\"#blanket-implementations\">\
+                        Blanket Implementations</a>",
+                );
+                out.push_str(&format!("<div class=\"sidebar-links\">{}</div>", blanket_format));
+            }
+        }
+    }
+
+    out
+}
+
+fn sidebar_struct(buf: &mut Buffer, it: &clean::Item, s: &clean::Struct) {
+    let mut sidebar = String::new();
+    let fields = get_struct_fields_name(&s.fields);
+
+    if !fields.is_empty() {
+        if let doctree::Plain = s.struct_type {
+            sidebar.push_str(&format!(
+                "<a class=\"sidebar-title\" href=\"#fields\">Fields</a>\
+                                       <div class=\"sidebar-links\">{}</div>",
+                fields
+            ));
+        }
+    }
+
+    sidebar.push_str(&sidebar_assoc_items(it));
+
+    if !sidebar.is_empty() {
+        write!(buf, "<div class=\"block items\">{}</div>", sidebar);
+    }
+}
+
+fn get_id_for_impl_on_foreign_type(for_: &clean::Type, trait_: &clean::Type) -> String {
+    small_url_encode(&format!("impl-{:#}-for-{:#}", trait_.print(), for_.print()))
+}
+
+fn extract_for_impl_name(item: &clean::Item) -> Option<(String, String)> {
+    match item.inner {
+        clean::ItemEnum::ImplItem(ref i) => {
+            if let Some(ref trait_) = i.trait_ {
+                Some((
+                    format!("{:#}", i.for_.print()),
+                    get_id_for_impl_on_foreign_type(&i.for_, trait_),
+                ))
+            } else {
+                None
+            }
+        }
+        _ => None,
+    }
+}
+
+fn is_negative_impl(i: &clean::Impl) -> bool {
+    i.polarity == Some(clean::ImplPolarity::Negative)
+}
+
+fn sidebar_trait(buf: &mut Buffer, it: &clean::Item, t: &clean::Trait) {
+    let mut sidebar = String::new();
+
+    let mut types = t
+        .items
+        .iter()
+        .filter_map(|m| match m.name {
+            Some(ref name) if m.is_associated_type() => {
+                Some(format!("<a href=\"#associatedtype.{name}\">{name}</a>", name = name))
+            }
+            _ => None,
+        })
+        .collect::<Vec<_>>();
+    let mut consts = t
+        .items
+        .iter()
+        .filter_map(|m| match m.name {
+            Some(ref name) if m.is_associated_const() => {
+                Some(format!("<a href=\"#associatedconstant.{name}\">{name}</a>", name = name))
+            }
+            _ => None,
+        })
+        .collect::<Vec<_>>();
+    let mut required = t
+        .items
+        .iter()
+        .filter_map(|m| match m.name {
+            Some(ref name) if m.is_ty_method() => {
+                Some(format!("<a href=\"#tymethod.{name}\">{name}</a>", name = name))
+            }
+            _ => None,
+        })
+        .collect::<Vec<String>>();
+    let mut provided = t
+        .items
+        .iter()
+        .filter_map(|m| match m.name {
+            Some(ref name) if m.is_method() => {
+                Some(format!("<a href=\"#method.{0}\">{0}</a>", name))
+            }
+            _ => None,
+        })
+        .collect::<Vec<String>>();
+
+    if !types.is_empty() {
+        types.sort();
+        sidebar.push_str(&format!(
+            "<a class=\"sidebar-title\" href=\"#associated-types\">\
+                Associated Types</a><div class=\"sidebar-links\">{}</div>",
+            types.join("")
+        ));
+    }
+    if !consts.is_empty() {
+        consts.sort();
+        sidebar.push_str(&format!(
+            "<a class=\"sidebar-title\" href=\"#associated-const\">\
+                Associated Constants</a><div class=\"sidebar-links\">{}</div>",
+            consts.join("")
+        ));
+    }
+    if !required.is_empty() {
+        required.sort();
+        sidebar.push_str(&format!(
+            "<a class=\"sidebar-title\" href=\"#required-methods\">\
+                Required Methods</a><div class=\"sidebar-links\">{}</div>",
+            required.join("")
+        ));
+    }
+    if !provided.is_empty() {
+        provided.sort();
+        sidebar.push_str(&format!(
+            "<a class=\"sidebar-title\" href=\"#provided-methods\">\
+                Provided Methods</a><div class=\"sidebar-links\">{}</div>",
+            provided.join("")
+        ));
+    }
+
+    let c = cache();
+
+    if let Some(implementors) = c.implementors.get(&it.def_id) {
+        let mut res = implementors
+            .iter()
+            .filter(|i| i.inner_impl().for_.def_id().map_or(false, |d| !c.paths.contains_key(&d)))
+            .filter_map(|i| extract_for_impl_name(&i.impl_item))
+            .collect::<Vec<_>>();
+
+        if !res.is_empty() {
+            res.sort();
+            sidebar.push_str(&format!(
+                "<a class=\"sidebar-title\" href=\"#foreign-impls\">\
+                    Implementations on Foreign Types</a><div \
+                    class=\"sidebar-links\">{}</div>",
+                res.into_iter()
+                    .map(|(name, id)| format!("<a href=\"#{}\">{}</a>", id, Escape(&name)))
+                    .collect::<Vec<_>>()
+                    .join("")
+            ));
+        }
+    }
+
+    sidebar.push_str(&sidebar_assoc_items(it));
+
+    sidebar.push_str("<a class=\"sidebar-title\" href=\"#implementors\">Implementors</a>");
+    if t.auto {
+        sidebar.push_str(
+            "<a class=\"sidebar-title\" \
+                href=\"#synthetic-implementors\">Auto Implementors</a>",
+        );
+    }
+
+    write!(buf, "<div class=\"block items\">{}</div>", sidebar)
+}
+
+fn sidebar_primitive(buf: &mut Buffer, it: &clean::Item) {
+    let sidebar = sidebar_assoc_items(it);
+
+    if !sidebar.is_empty() {
+        write!(buf, "<div class=\"block items\">{}</div>", sidebar);
+    }
+}
+
+fn sidebar_typedef(buf: &mut Buffer, it: &clean::Item) {
+    let sidebar = sidebar_assoc_items(it);
+
+    if !sidebar.is_empty() {
+        write!(buf, "<div class=\"block items\">{}</div>", sidebar);
+    }
+}
+
+fn get_struct_fields_name(fields: &[clean::Item]) -> String {
+    let mut fields = fields
+        .iter()
+        .filter(|f| if let clean::StructFieldItem(..) = f.inner { true } else { false })
+        .filter_map(|f| match f.name {
+            Some(ref name) => {
+                Some(format!("<a href=\"#structfield.{name}\">{name}</a>", name = name))
+            }
+            _ => None,
+        })
+        .collect::<Vec<_>>();
+    fields.sort();
+    fields.join("")
+}
+
+fn sidebar_union(buf: &mut Buffer, it: &clean::Item, u: &clean::Union) {
+    let mut sidebar = String::new();
+    let fields = get_struct_fields_name(&u.fields);
+
+    if !fields.is_empty() {
+        sidebar.push_str(&format!(
+            "<a class=\"sidebar-title\" href=\"#fields\">Fields</a>\
+             <div class=\"sidebar-links\">{}</div>",
+            fields
+        ));
+    }
+
+    sidebar.push_str(&sidebar_assoc_items(it));
+
+    if !sidebar.is_empty() {
+        write!(buf, "<div class=\"block items\">{}</div>", sidebar);
+    }
+}
+
+fn sidebar_enum(buf: &mut Buffer, it: &clean::Item, e: &clean::Enum) {
+    let mut sidebar = String::new();
+
+    let mut variants = e
+        .variants
+        .iter()
+        .filter_map(|v| match v.name {
+            Some(ref name) => Some(format!("<a href=\"#variant.{name}\">{name}</a>", name = name)),
+            _ => None,
+        })
+        .collect::<Vec<_>>();
+    if !variants.is_empty() {
+        variants.sort_unstable();
+        sidebar.push_str(&format!(
+            "<a class=\"sidebar-title\" href=\"#variants\">Variants</a>\
+             <div class=\"sidebar-links\">{}</div>",
+            variants.join(""),
+        ));
+    }
+
+    sidebar.push_str(&sidebar_assoc_items(it));
+
+    if !sidebar.is_empty() {
+        write!(buf, "<div class=\"block items\">{}</div>", sidebar);
+    }
+}
+
+fn item_ty_to_strs(ty: &ItemType) -> (&'static str, &'static str) {
+    match *ty {
+        ItemType::ExternCrate | ItemType::Import => ("reexports", "Re-exports"),
+        ItemType::Module => ("modules", "Modules"),
+        ItemType::Struct => ("structs", "Structs"),
+        ItemType::Union => ("unions", "Unions"),
+        ItemType::Enum => ("enums", "Enums"),
+        ItemType::Function => ("functions", "Functions"),
+        ItemType::Typedef => ("types", "Type Definitions"),
+        ItemType::Static => ("statics", "Statics"),
+        ItemType::Constant => ("constants", "Constants"),
+        ItemType::Trait => ("traits", "Traits"),
+        ItemType::Impl => ("impls", "Implementations"),
+        ItemType::TyMethod => ("tymethods", "Type Methods"),
+        ItemType::Method => ("methods", "Methods"),
+        ItemType::StructField => ("fields", "Struct Fields"),
+        ItemType::Variant => ("variants", "Variants"),
+        ItemType::Macro => ("macros", "Macros"),
+        ItemType::Primitive => ("primitives", "Primitive Types"),
+        ItemType::AssocType => ("associated-types", "Associated Types"),
+        ItemType::AssocConst => ("associated-consts", "Associated Constants"),
+        ItemType::ForeignType => ("foreign-types", "Foreign Types"),
+        ItemType::Keyword => ("keywords", "Keywords"),
+        ItemType::OpaqueTy => ("opaque-types", "Opaque Types"),
+        ItemType::ProcAttribute => ("attributes", "Attribute Macros"),
+        ItemType::ProcDerive => ("derives", "Derive Macros"),
+        ItemType::TraitAlias => ("trait-aliases", "Trait aliases"),
+    }
+}
+
+fn sidebar_module(buf: &mut Buffer, items: &[clean::Item]) {
+    let mut sidebar = String::new();
+
+    if items.iter().any(|it| it.type_() == ItemType::ExternCrate || it.type_() == ItemType::Import)
+    {
+        sidebar.push_str(&format!(
+            "<li><a href=\"#{id}\">{name}</a></li>",
+            id = "reexports",
+            name = "Re-exports"
+        ));
+    }
+
+    // ordering taken from item_module, reorder, where it prioritized elements in a certain order
+    // to print its headings
+    for &myty in &[
+        ItemType::Primitive,
+        ItemType::Module,
+        ItemType::Macro,
+        ItemType::Struct,
+        ItemType::Enum,
+        ItemType::Constant,
+        ItemType::Static,
+        ItemType::Trait,
+        ItemType::Function,
+        ItemType::Typedef,
+        ItemType::Union,
+        ItemType::Impl,
+        ItemType::TyMethod,
+        ItemType::Method,
+        ItemType::StructField,
+        ItemType::Variant,
+        ItemType::AssocType,
+        ItemType::AssocConst,
+        ItemType::ForeignType,
+        ItemType::Keyword,
+    ] {
+        if items.iter().any(|it| !it.is_stripped() && it.type_() == myty) {
+            let (short, name) = item_ty_to_strs(&myty);
+            sidebar.push_str(&format!(
+                "<li><a href=\"#{id}\">{name}</a></li>",
+                id = short,
+                name = name
+            ));
+        }
+    }
+
+    if !sidebar.is_empty() {
+        write!(buf, "<div class=\"block items\"><ul>{}</ul></div>", sidebar);
+    }
+}
+
+fn sidebar_foreign_type(buf: &mut Buffer, it: &clean::Item) {
+    let sidebar = sidebar_assoc_items(it);
+    if !sidebar.is_empty() {
+        write!(buf, "<div class=\"block items\">{}</div>", sidebar);
+    }
+}
+
+fn item_macro(w: &mut Buffer, cx: &Context, it: &clean::Item, t: &clean::Macro) {
+    wrap_into_docblock(w, |w| {
+        w.write_str(&highlight::render_with_highlighting(
+            t.source.clone(),
+            Some("macro"),
+            None,
+            None,
+        ))
+    });
+    document(w, cx, it)
+}
+
+fn item_proc_macro(w: &mut Buffer, cx: &Context, it: &clean::Item, m: &clean::ProcMacro) {
+    let name = it.name.as_ref().expect("proc-macros always have names");
+    match m.kind {
+        MacroKind::Bang => {
+            write!(w, "<pre class='rust macro'>");
+            write!(w, "{}!() {{ /* proc-macro */ }}", name);
+            write!(w, "</pre>");
+        }
+        MacroKind::Attr => {
+            write!(w, "<pre class='rust attr'>");
+            write!(w, "#[{}]", name);
+            write!(w, "</pre>");
+        }
+        MacroKind::Derive => {
+            write!(w, "<pre class='rust derive'>");
+            write!(w, "#[derive({})]", name);
+            if !m.helpers.is_empty() {
+                writeln!(w, "\n{{");
+                writeln!(w, "    // Attributes available to this derive:");
+                for attr in &m.helpers {
+                    writeln!(w, "    #[{}]", attr);
+                }
+                write!(w, "}}");
+            }
+            write!(w, "</pre>");
+        }
+    }
+    document(w, cx, it)
+}
+
+fn item_primitive(w: &mut Buffer, cx: &Context, it: &clean::Item, cache: &Cache) {
+    document(w, cx, it);
+    render_assoc_items(w, cx, it, it.def_id, AssocItemRender::All, cache)
+}
+
+fn item_keyword(w: &mut Buffer, cx: &Context, it: &clean::Item) {
+    document(w, cx, it)
+}
+
+crate const BASIC_KEYWORDS: &str = "rust, rustlang, rust-lang";
+
+fn make_item_keywords(it: &clean::Item) -> String {
+    format!("{}, {}", BASIC_KEYWORDS, it.name.as_ref().unwrap())
+}
+
+/// Returns a list of all paths used in the type.
+/// This is used to help deduplicate imported impls
+/// for reexported types. If any of the contained
+/// types are re-exported, we don't use the corresponding
+/// entry from the js file, as inlining will have already
+/// picked up the impl
+fn collect_paths_for_type(first_ty: clean::Type) -> Vec<String> {
+    let mut out = Vec::new();
+    let mut visited = FxHashSet::default();
+    let mut work = VecDeque::new();
+    let cache = cache();
+
+    work.push_back(first_ty);
+
+    while let Some(ty) = work.pop_front() {
+        if !visited.insert(ty.clone()) {
+            continue;
+        }
+
+        match ty {
+            clean::Type::ResolvedPath { did, .. } => {
+                let get_extern = || cache.external_paths.get(&did).map(|s| s.0.clone());
+                let fqp = cache.exact_paths.get(&did).cloned().or_else(get_extern);
+
+                if let Some(path) = fqp {
+                    out.push(path.join("::"));
+                }
+            }
+            clean::Type::Tuple(tys) => {
+                work.extend(tys.into_iter());
+            }
+            clean::Type::Slice(ty) => {
+                work.push_back(*ty);
+            }
+            clean::Type::Array(ty, _) => {
+                work.push_back(*ty);
+            }
+            clean::Type::RawPointer(_, ty) => {
+                work.push_back(*ty);
+            }
+            clean::Type::BorrowedRef { type_, .. } => {
+                work.push_back(*type_);
+            }
+            clean::Type::QPath { self_type, trait_, .. } => {
+                work.push_back(*self_type);
+                work.push_back(*trait_);
+            }
+            _ => {}
+        }
+    }
+    out
+}