diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index b683626bbd64d..52a6e4ff924f4 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -797,7 +797,7 @@ pub const fn default_lib_output() -> CrateType {
     CrateType::Rlib
 }
 
-pub fn default_configuration(sess: &Session) -> CrateConfig {
+fn default_configuration(sess: &Session) -> CrateConfig {
     let end = &sess.target.endian;
     let arch = &sess.target.arch;
     let wordsz = sess.target.pointer_width.to_string();
@@ -892,7 +892,7 @@ pub fn build_configuration(sess: &Session, mut user_cfg: CrateConfig) -> CrateCo
     user_cfg
 }
 
-pub fn build_target_config(opts: &Options, target_override: Option<Target>) -> Target {
+pub(super) fn build_target_config(opts: &Options, target_override: Option<Target>) -> Target {
     let target_result = target_override.map_or_else(|| Target::search(&opts.target_triple), Ok);
     let target = target_result.unwrap_or_else(|e| {
         early_error(
diff --git a/library/alloc/src/task.rs b/library/alloc/src/task.rs
index 58a9ae77244fb..528ee4ff1542c 100644
--- a/library/alloc/src/task.rs
+++ b/library/alloc/src/task.rs
@@ -87,6 +87,9 @@ pub trait Wake {
 
 #[stable(feature = "wake_trait", since = "1.51.0")]
 impl<W: Wake + Send + Sync + 'static> From<Arc<W>> for Waker {
+    /// Use a `Wake`-able type as a `Waker`.
+    ///
+    /// No heap allocations or atomic operations are used for this conversion.
     fn from(waker: Arc<W>) -> Waker {
         // SAFETY: This is safe because raw_waker safely constructs
         // a RawWaker from Arc<W>.
@@ -96,6 +99,9 @@ impl<W: Wake + Send + Sync + 'static> From<Arc<W>> for Waker {
 
 #[stable(feature = "wake_trait", since = "1.51.0")]
 impl<W: Wake + Send + Sync + 'static> From<Arc<W>> for RawWaker {
+    /// Use a `Wake`-able type as a `RawWaker`.
+    ///
+    /// No heap allocations or atomic operations are used for this conversion.
     fn from(waker: Arc<W>) -> RawWaker {
         raw_waker(waker)
     }
diff --git a/library/core/src/iter/adapters/take.rs b/library/core/src/iter/adapters/take.rs
index 9efc7a480aeb4..54a47f1323ebf 100644
--- a/library/core/src/iter/adapters/take.rs
+++ b/library/core/src/iter/adapters/take.rs
@@ -1,5 +1,8 @@
 use crate::cmp;
-use crate::iter::{adapters::SourceIter, FusedIterator, InPlaceIterable, TrustedLen};
+use crate::iter::{
+    adapters::zip::try_get_unchecked, adapters::SourceIter, FusedIterator, InPlaceIterable,
+    TrustedLen, TrustedRandomAccess,
+};
 use crate::ops::{ControlFlow, Try};
 
 /// An iterator that only iterates over the first `n` iterations of `iter`.
@@ -111,6 +114,15 @@ where
 
         self.try_fold(init, ok(fold)).unwrap()
     }
+
+    unsafe fn __iterator_get_unchecked(&mut self, idx: usize) -> <I as Iterator>::Item
+    where
+        Self: TrustedRandomAccess,
+    {
+        // SAFETY: the caller must uphold the contract for
+        // `Iterator::__iterator_get_unchecked`.
+        unsafe { try_get_unchecked(&mut self.iter, idx) }
+    }
 }
 
 #[unstable(issue = "none", feature = "inplace_iteration")]
@@ -207,3 +219,12 @@ impl<I> FusedIterator for Take<I> where I: FusedIterator {}
 
 #[unstable(feature = "trusted_len", issue = "37572")]
 unsafe impl<I: TrustedLen> TrustedLen for Take<I> {}
+
+#[doc(hidden)]
+#[unstable(feature = "trusted_random_access", issue = "none")]
+unsafe impl<I> TrustedRandomAccess for Take<I>
+where
+    I: TrustedRandomAccess,
+{
+    const MAY_HAVE_SIDE_EFFECT: bool = I::MAY_HAVE_SIDE_EFFECT;
+}
diff --git a/library/core/src/iter/traits/iterator.rs b/library/core/src/iter/traits/iterator.rs
index 9b0f9544f8efc..7977d599ae725 100644
--- a/library/core/src/iter/traits/iterator.rs
+++ b/library/core/src/iter/traits/iterator.rs
@@ -1495,7 +1495,12 @@ pub trait Iterator {
     /// [`Some(T)`] again. `fuse()` adapts an iterator, ensuring that after a
     /// [`None`] is given, it will always return [`None`] forever.
     ///
+    /// Note that the [`Fuse`] wrapper is a no-op on iterators that implement
+    /// the [`FusedIterator`] trait. `fuse()` may therefore behave incorrectly
+    /// if the [`FusedIterator`] trait is improperly implemented.
+    ///
     /// [`Some(T)`]: Some
+    /// [`FusedIterator`]: crate::iter::FusedIterator
     ///
     /// # Examples
     ///
diff --git a/src/bootstrap/install.rs b/src/bootstrap/install.rs
index 68e7dc8006726..13ee909afd5e4 100644
--- a/src/bootstrap/install.rs
+++ b/src/bootstrap/install.rs
@@ -17,6 +17,11 @@ use crate::Compiler;
 use crate::builder::{Builder, RunConfig, ShouldRun, Step};
 use crate::config::{Config, TargetSelection};
 
+#[cfg(target_os = "illumos")]
+const SHELL: &str = "bash";
+#[cfg(not(target_os = "illumos"))]
+const SHELL: &str = "sh";
+
 fn install_sh(
     builder: &Builder<'_>,
     package: &str,
@@ -37,7 +42,7 @@ fn install_sh(
     let empty_dir = builder.out.join("tmp/empty_dir");
     t!(fs::create_dir_all(&empty_dir));
 
-    let mut cmd = Command::new("sh");
+    let mut cmd = Command::new(SHELL);
     cmd.current_dir(&empty_dir)
         .arg(sanitize_sh(&tarball.decompressed_output().join("install.sh")))
         .arg(format!("--prefix={}", prepare_dir(prefix)))
diff --git a/src/librustdoc/formats/renderer.rs b/src/librustdoc/formats/renderer.rs
index ae97cd64fb5fb..b8ef3384c5908 100644
--- a/src/librustdoc/formats/renderer.rs
+++ b/src/librustdoc/formats/renderer.rs
@@ -1,5 +1,5 @@
 use rustc_middle::ty::TyCtxt;
-use rustc_span::{edition::Edition, Symbol};
+use rustc_span::Symbol;
 
 use crate::clean;
 use crate::config::RenderOptions;
@@ -23,7 +23,6 @@ crate trait FormatRenderer<'tcx>: Sized {
     fn init(
         krate: clean::Crate,
         options: RenderOptions,
-        edition: Edition,
         cache: Cache,
         tcx: TyCtxt<'tcx>,
     ) -> Result<(Self, clean::Crate), Error>;
@@ -35,19 +34,15 @@ crate trait FormatRenderer<'tcx>: Sized {
     fn item(&mut self, item: clean::Item) -> Result<(), Error>;
 
     /// Renders a module (should not handle recursing into children).
-    fn mod_item_in(&mut self, item: &clean::Item, item_name: &str) -> Result<(), Error>;
+    fn mod_item_in(&mut self, item: &clean::Item) -> Result<(), Error>;
 
     /// Runs after recursively rendering all sub-items of a module.
-    fn mod_item_out(&mut self, item_name: &str) -> Result<(), Error>;
+    fn mod_item_out(&mut self) -> Result<(), Error> {
+        Ok(())
+    }
 
     /// Post processing hook for cleanup and dumping output to files.
-    ///
-    /// A handler is available if the renderer wants to report errors.
-    fn after_krate(
-        &mut self,
-        crate_name: Symbol,
-        diag: &rustc_errors::Handler,
-    ) -> Result<(), Error>;
+    fn after_krate(&mut self) -> Result<(), Error>;
 
     fn cache(&self) -> &Cache;
 }
@@ -57,8 +52,6 @@ crate fn run_format<'tcx, T: FormatRenderer<'tcx>>(
     krate: clean::Crate,
     options: RenderOptions,
     cache: Cache,
-    diag: &rustc_errors::Handler,
-    edition: Edition,
     tcx: TyCtxt<'tcx>,
 ) -> Result<(), Error> {
     let prof = &tcx.sess.prof;
@@ -66,14 +59,13 @@ crate fn run_format<'tcx, T: FormatRenderer<'tcx>>(
     let emit_crate = options.should_emit_crate();
     let (mut format_renderer, krate) = prof
         .extra_verbose_generic_activity("create_renderer", T::descr())
-        .run(|| T::init(krate, options, edition, cache, tcx))?;
+        .run(|| T::init(krate, options, cache, tcx))?;
 
     if !emit_crate {
         return Ok(());
     }
 
     // Render the crate documentation
-    let crate_name = krate.name;
     let mut work = vec![(format_renderer.make_child_renderer(), krate.module)];
 
     let unknown = Symbol::intern("<unknown item>");
@@ -81,13 +73,10 @@ crate fn run_format<'tcx, T: FormatRenderer<'tcx>>(
         if item.is_mod() && T::RUN_ON_MODULE {
             // modules are special because they add a namespace. We also need to
             // recurse into the items of the module as well.
-            let name = item.name.as_ref().unwrap().to_string();
-            if name.is_empty() {
-                panic!("Unexpected module with empty name");
-            }
-            let _timer = prof.generic_activity_with_arg("render_mod_item", name.as_str());
+            let _timer =
+                prof.generic_activity_with_arg("render_mod_item", item.name.unwrap().to_string());
 
-            cx.mod_item_in(&item, &name)?;
+            cx.mod_item_in(&item)?;
             let module = match *item.kind {
                 clean::StrippedItem(box clean::ModuleItem(m)) | clean::ModuleItem(m) => m,
                 _ => unreachable!(),
@@ -97,7 +86,7 @@ crate fn run_format<'tcx, T: FormatRenderer<'tcx>>(
                 work.push((cx.make_child_renderer(), it));
             }
 
-            cx.mod_item_out(&name)?;
+            cx.mod_item_out()?;
         // FIXME: checking `item.name.is_some()` is very implicit and leads to lots of special
         // cases. Use an explicit match instead.
         } else if item.name.is_some() && !item.is_extern_crate() {
@@ -106,5 +95,5 @@ crate fn run_format<'tcx, T: FormatRenderer<'tcx>>(
         }
     }
     prof.extra_verbose_generic_activity("renderer_after_krate", T::descr())
-        .run(|| format_renderer.after_krate(crate_name, diag))
+        .run(|| format_renderer.after_krate())
 }
diff --git a/src/librustdoc/html/render/context.rs b/src/librustdoc/html/render/context.rs
index 0aa7aa763c2af..9cffcef9749f8 100644
--- a/src/librustdoc/html/render/context.rs
+++ b/src/librustdoc/html/render/context.rs
@@ -11,7 +11,7 @@ use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
 use rustc_span::edition::Edition;
 use rustc_span::source_map::FileName;
-use rustc_span::{symbol::sym, Symbol};
+use rustc_span::symbol::sym;
 
 use super::cache::{build_index, ExternalLocation};
 use super::print_item::{full_path, item_path, print_item};
@@ -111,8 +111,6 @@ crate struct SharedContext<'tcx> {
     crate static_root_path: Option<String>,
     /// The fs handle we are working with.
     crate fs: DocFS,
-    /// The default edition used to parse doctests.
-    crate edition: Edition,
     pub(super) codes: ErrorCodes,
     pub(super) playground: Option<markdown::Playground>,
     all: RefCell<AllTypes>,
@@ -141,6 +139,10 @@ impl SharedContext<'_> {
     crate fn maybe_collapsed_doc_value<'a>(&self, item: &'a clean::Item) -> Option<String> {
         if self.collapsed { item.collapsed_doc_value() } else { item.doc_value() }
     }
+
+    crate fn edition(&self) -> Edition {
+        self.tcx.sess.edition()
+    }
 }
 
 impl<'tcx> Context<'tcx> {
@@ -346,7 +348,6 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
     fn init(
         mut krate: clean::Crate,
         options: RenderOptions,
-        edition: Edition,
         mut cache: Cache,
         tcx: TyCtxt<'tcx>,
     ) -> Result<(Self, clean::Crate), Error> {
@@ -435,7 +436,6 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
             resource_suffix,
             static_root_path,
             fs: DocFS::new(sender),
-            edition,
             codes: ErrorCodes::from(unstable_features.is_nightly_build()),
             playground,
             all: RefCell::new(AllTypes::new()),
@@ -494,11 +494,8 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
         }
     }
 
-    fn after_krate(
-        &mut self,
-        crate_name: Symbol,
-        diag: &rustc_errors::Handler,
-    ) -> Result<(), Error> {
+    fn after_krate(&mut self) -> Result<(), Error> {
+        let crate_name = self.tcx().crate_name(LOCAL_CRATE);
         let final_file = self.dst.join(&*crate_name.as_str()).join("all.html");
         let settings_file = self.dst.join("settings.html");
 
@@ -572,7 +569,8 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
 
         // Flush pending errors.
         Rc::get_mut(&mut self.shared).unwrap().fs.close();
-        let nb_errors = self.shared.errors.iter().map(|err| diag.struct_err(&err).emit()).count();
+        let nb_errors =
+            self.shared.errors.iter().map(|err| self.tcx().sess.struct_err(&err).emit()).count();
         if nb_errors > 0 {
             Err(Error::new(io::Error::new(io::ErrorKind::Other, "I/O error"), ""))
         } else {
@@ -580,7 +578,7 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
         }
     }
 
-    fn mod_item_in(&mut self, item: &clean::Item, item_name: &str) -> Result<(), Error> {
+    fn mod_item_in(&mut self, item: &clean::Item) -> 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.
@@ -592,8 +590,9 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
             self.render_redirect_pages = item.is_stripped();
         }
         let scx = &self.shared;
-        self.dst.push(item_name);
-        self.current.push(item_name.to_owned());
+        let item_name = item.name.as_ref().unwrap().to_string();
+        self.dst.push(&item_name);
+        self.current.push(item_name);
 
         info!("Recursing into {}", self.dst.display());
 
@@ -619,7 +618,7 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
         Ok(())
     }
 
-    fn mod_item_out(&mut self, _item_name: &str) -> Result<(), Error> {
+    fn mod_item_out(&mut self) -> Result<(), Error> {
         info!("Recursed; leaving {}", self.dst.display());
 
         // Go back to where we were at
diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index d773f37ad90a3..f6d6b34f8bef9 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -530,7 +530,7 @@ fn render_markdown(
             &links,
             &mut ids,
             cx.shared.codes,
-            cx.shared.edition,
+            cx.shared.edition(),
             &cx.shared.playground
         )
         .into_string()
@@ -660,7 +660,7 @@ fn short_item_info(
                 &note,
                 &mut ids,
                 error_codes,
-                cx.shared.edition,
+                cx.shared.edition(),
                 &cx.shared.playground,
             );
             message.push_str(&format!(": {}", html.into_string()));
@@ -702,7 +702,7 @@ fn short_item_info(
                     &unstable_reason.as_str(),
                     &mut ids,
                     error_codes,
-                    cx.shared.edition,
+                    cx.shared.edition(),
                     &cx.shared.playground,
                 )
                 .into_string()
@@ -1284,6 +1284,7 @@ fn render_impl(
     let cache = cx.cache();
     let traits = &cache.traits;
     let trait_ = i.trait_did_full(cache).map(|did| &traits[&did]);
+    let mut close_tags = String::new();
 
     if render_mode == RenderMode::Normal {
         let id = cx.derive_id(match i.inner_impl().trait_ {
@@ -1302,7 +1303,12 @@ fn render_impl(
             format!(" aliases=\"{}\"", aliases.join(","))
         };
         if let Some(use_absolute) = use_absolute {
-            write!(w, "<h3 id=\"{}\" class=\"impl\"{}><code class=\"in-band\">", id, aliases);
+            write!(
+                w,
+                "<details class=\"rustdoc-toggle implementors-toggle\"><summary><h3 id=\"{}\" class=\"impl\"{}><code class=\"in-band\">",
+                id, aliases
+            );
+            close_tags.insert_str(0, "</details>");
             write!(w, "{}", i.inner_impl().print(use_absolute, cx));
             if show_def_docs {
                 for it in &i.inner_impl().items {
@@ -1325,11 +1331,12 @@ fn render_impl(
         } else {
             write!(
                 w,
-                "<h3 id=\"{}\" class=\"impl\"{}><code class=\"in-band\">{}</code>",
+                "<details class=\"rustdoc-toggle implementors-toggle\"><summary><h3 id=\"{}\" class=\"impl\"{}><code class=\"in-band\">{}</code>",
                 id,
                 aliases,
                 i.inner_impl().print(false, cx)
             );
+            close_tags.insert_str(0, "</details>");
         }
         write!(w, "<a href=\"#{}\" class=\"anchor\"></a>", id);
         render_stability_since_raw(
@@ -1341,6 +1348,7 @@ fn render_impl(
         );
         write_srclink(cx, &i.impl_item, w);
         w.write_str("</h3>");
+        w.write_str("</summary>");
 
         if trait_.is_some() {
             if let Some(portability) = portability(&i.impl_item, Some(parent)) {
@@ -1358,7 +1366,7 @@ fn render_impl(
                     &i.impl_item.links(cx),
                     &mut ids,
                     cx.shared.codes,
-                    cx.shared.edition,
+                    cx.shared.edition(),
                     &cx.shared.playground
                 )
                 .into_string()
@@ -1542,6 +1550,7 @@ fn render_impl(
     }
 
     w.write_str("<div class=\"impl-items\">");
+    close_tags.insert_str(0, "</div>");
     for trait_item in &i.inner_impl().items {
         doc_impl_item(
             w,
@@ -1612,7 +1621,7 @@ fn render_impl(
             );
         }
     }
-    w.write_str("</div>");
+    w.write_str(&close_tags);
 }
 
 fn print_sidebar(cx: &Context<'_>, it: &clean::Item, buffer: &mut Buffer) {
diff --git a/src/librustdoc/html/render/write_shared.rs b/src/librustdoc/html/render/write_shared.rs
index 78bcd40af7538..8e10c696df05d 100644
--- a/src/librustdoc/html/render/write_shared.rs
+++ b/src/librustdoc/html/render/write_shared.rs
@@ -425,7 +425,7 @@ pub(super) fn write_shared(
             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)
+            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");
diff --git a/src/librustdoc/html/sources.rs b/src/librustdoc/html/sources.rs
index 001c8b090448b..5a2a165191a60 100644
--- a/src/librustdoc/html/sources.rs
+++ b/src/librustdoc/html/sources.rs
@@ -129,7 +129,7 @@ impl SourceCollector<'_, 'tcx> {
             &self.scx.layout,
             &page,
             "",
-            |buf: &mut _| print_src(buf, contents, self.scx.edition),
+            |buf: &mut _| print_src(buf, contents, self.scx.edition()),
             &self.scx.style_files,
         );
         self.scx.fs.write(&cur, v.as_bytes())?;
diff --git a/src/librustdoc/html/static/main.js b/src/librustdoc/html/static/main.js
index 5dfc206eb2e2d..2e3e148eaf695 100644
--- a/src/librustdoc/html/static/main.js
+++ b/src/librustdoc/html/static/main.js
@@ -1207,31 +1207,18 @@ function hideThemeButtonState() {
             if (!next) {
                 return;
             }
-            if (hasClass(e, "impl") &&
-                (next.getElementsByClassName("method").length > 0 ||
-                 next.getElementsByClassName("associatedconstant").length > 0)) {
-                var newToggle = toggle.cloneNode(true);
-                insertAfter(newToggle, e.childNodes[e.childNodes.length - 1]);
-                // In case the option "auto-collapse implementors" is not set to false, we collapse
-                // all implementors.
-                if (hideImplementors === true && e.parentNode.id === "implementors-list") {
-                    collapseDocs(newToggle, "hide");
-                }
-            }
         };
 
         onEachLazy(document.getElementsByClassName("method"), func);
         onEachLazy(document.getElementsByClassName("associatedconstant"), func);
-        onEachLazy(document.getElementsByClassName("impl"), funcImpl);
         var impl_call = function() {};
-        // Large items are hidden by default in the HTML. If the setting overrides that, show 'em.
-        if (!hideLargeItemContents) {
-            onEachLazy(document.getElementsByTagName("details"), function (e) {
-                if (hasClass(e, "type-contents-toggle")) {
-                    e.open = true;
-                }
-            });
-        }
+        onEachLazy(document.getElementsByTagName("details"), function (e) {
+            var showLargeItem = !hideLargeItemContents && hasClass(e, "type-contents-toggle");
+            var showImplementor = !hideImplementors && hasClass(e, "implementors-toggle");
+            if (showLargeItem || showImplementor) {
+                e.open = true;
+            }
+        });
         if (hideMethodDocs === true) {
             impl_call = function(e, newToggle) {
                 if (e.id.match(/^impl(?:-\d+)?$/) === null) {
diff --git a/src/librustdoc/html/static/rustdoc.css b/src/librustdoc/html/static/rustdoc.css
index 44fb531100ae4..a024fa49b0e8b 100644
--- a/src/librustdoc/html/static/rustdoc.css
+++ b/src/librustdoc/html/static/rustdoc.css
@@ -1573,6 +1573,10 @@ h4 > .notable-traits {
 		left: -10px;
 	}
 
+	.item-list > details.rustdoc-toggle > summary:not(.hideme)::before {
+		left: -10px;
+	}
+
 	#all-types {
 		margin: 10px;
 	}
@@ -1787,6 +1791,7 @@ details.rustdoc-toggle > summary::before {
 	font-weight: 300;
 	font-size: 0.8em;
 	letter-spacing: 1px;
+	cursor: pointer;
 }
 
 details.rustdoc-toggle > summary.hideme::before {
@@ -1794,7 +1799,8 @@ details.rustdoc-toggle > summary.hideme::before {
 }
 
 details.rustdoc-toggle > summary:not(.hideme)::before {
-	float: left;
+	position: absolute;
+	left: -23px;
 }
 
 /* When a "hideme" summary is open and the "Expand description" or "Show
diff --git a/src/librustdoc/json/mod.rs b/src/librustdoc/json/mod.rs
index db3a0c5ceb167..b048e7f919fa4 100644
--- a/src/librustdoc/json/mod.rs
+++ b/src/librustdoc/json/mod.rs
@@ -14,7 +14,6 @@ use std::rc::Rc;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
-use rustc_span::{edition::Edition, Symbol};
 
 use rustdoc_json_types as types;
 
@@ -134,7 +133,6 @@ impl<'tcx> FormatRenderer<'tcx> for JsonRenderer<'tcx> {
     fn init(
         krate: clean::Crate,
         options: RenderOptions,
-        _edition: Edition,
         cache: Cache,
         tcx: TyCtxt<'tcx>,
     ) -> Result<(Self, clean::Crate), Error> {
@@ -183,7 +181,7 @@ impl<'tcx> FormatRenderer<'tcx> for JsonRenderer<'tcx> {
         Ok(())
     }
 
-    fn mod_item_in(&mut self, item: &clean::Item, _module_name: &str) -> Result<(), Error> {
+    fn mod_item_in(&mut self, item: &clean::Item) -> Result<(), Error> {
         use clean::types::ItemKind::*;
         if let ModuleItem(m) = &*item.kind {
             for item in &m.items {
@@ -200,15 +198,7 @@ impl<'tcx> FormatRenderer<'tcx> for JsonRenderer<'tcx> {
         Ok(())
     }
 
-    fn mod_item_out(&mut self, _item_name: &str) -> Result<(), Error> {
-        Ok(())
-    }
-
-    fn after_krate(
-        &mut self,
-        _crate_name: Symbol,
-        _diag: &rustc_errors::Handler,
-    ) -> Result<(), Error> {
+    fn after_krate(&mut self) -> Result<(), Error> {
         debug!("Done with crate");
         let mut index = (*self.index).clone().into_inner();
         index.extend(self.get_trait_items());
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 2a51d78f64a39..26aaf0db6f620 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -656,14 +656,13 @@ fn run_renderer<'tcx, T: formats::FormatRenderer<'tcx>>(
     krate: clean::Crate,
     renderopts: config::RenderOptions,
     cache: formats::cache::Cache,
-    diag: &rustc_errors::Handler,
-    edition: rustc_span::edition::Edition,
     tcx: TyCtxt<'tcx>,
 ) -> MainResult {
-    match formats::run_format::<T>(krate, renderopts, cache, &diag, edition, tcx) {
+    match formats::run_format::<T>(krate, renderopts, cache, tcx) {
         Ok(_) => Ok(()),
         Err(e) => {
-            let mut msg = diag.struct_err(&format!("couldn't generate documentation: {}", e.error));
+            let mut msg =
+                tcx.sess.struct_err(&format!("couldn't generate documentation: {}", e.error));
             let file = e.file.display().to_string();
             if file.is_empty() {
                 msg.emit()
@@ -692,7 +691,6 @@ fn main_options(options: config::Options) -> MainResult {
 
     // need to move these items separately because we lose them by the time the closure is called,
     // but we can't create the Handler ahead of time because it's not Send
-    let diag_opts = (options.error_format, options.edition, options.debugging_opts.clone());
     let show_coverage = options.show_coverage;
     let run_check = options.run_check;
 
@@ -758,28 +756,12 @@ fn main_options(options: config::Options) -> MainResult {
                 }
 
                 info!("going to format");
-                let (error_format, edition, debugging_options) = diag_opts;
-                let diag = core::new_handler(error_format, None, &debugging_options);
                 match output_format {
                     config::OutputFormat::Html => sess.time("render_html", || {
-                        run_renderer::<html::render::Context<'_>>(
-                            krate,
-                            render_opts,
-                            cache,
-                            &diag,
-                            edition,
-                            tcx,
-                        )
+                        run_renderer::<html::render::Context<'_>>(krate, render_opts, cache, tcx)
                     }),
                     config::OutputFormat::Json => sess.time("render_json", || {
-                        run_renderer::<json::JsonRenderer<'_>>(
-                            krate,
-                            render_opts,
-                            cache,
-                            &diag,
-                            edition,
-                            tcx,
-                        )
+                        run_renderer::<json::JsonRenderer<'_>>(krate, render_opts, cache, tcx)
                     }),
                 }
             })
diff --git a/src/librustdoc/visit_ast.rs b/src/librustdoc/visit_ast.rs
index ca30d8f0d4623..d852728b74962 100644
--- a/src/librustdoc/visit_ast.rs
+++ b/src/librustdoc/visit_ast.rs
@@ -71,9 +71,10 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
     }
 
     crate fn visit(mut self, krate: &'tcx hir::Crate<'_>) -> Module<'tcx> {
+        let span = krate.item.inner;
         let mut top_level_module = self.visit_mod_contents(
-            krate.item.inner,
-            &Spanned { span: rustc_span::DUMMY_SP, node: hir::VisibilityKind::Public },
+            span,
+            &Spanned { span, node: hir::VisibilityKind::Public },
             hir::CRATE_HIR_ID,
             &krate.item,
             self.cx.tcx.crate_name,
@@ -130,7 +131,7 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
     fn visit_mod_contents(
         &mut self,
         span: Span,
-        vis: &'tcx hir::Visibility<'_>,
+        vis: &hir::Visibility<'_>,
         id: hir::HirId,
         m: &'tcx hir::Mod<'tcx>,
         name: Symbol,
diff --git a/src/test/rustdoc/const-generics/add-impl.rs b/src/test/rustdoc/const-generics/add-impl.rs
index db4be82e6bfd9..77432ba153955 100644
--- a/src/test/rustdoc/const-generics/add-impl.rs
+++ b/src/test/rustdoc/const-generics/add-impl.rs
@@ -8,7 +8,7 @@ pub struct Simd<T, const WIDTH: usize> {
     inner: T,
 }
 
-// @has foo/struct.Simd.html '//div[@id="trait-implementations-list"]/h3/code' 'impl Add<Simd<u8, 16_usize>> for Simd<u8, 16>'
+// @has foo/struct.Simd.html '//div[@id="trait-implementations-list"]//h3/code' 'impl Add<Simd<u8, 16_usize>> for Simd<u8, 16>'
 impl Add for Simd<u8, 16> {
     type Output = Self;
 
diff --git a/src/test/rustdoc/duplicate_impls/issue-33054.rs b/src/test/rustdoc/duplicate_impls/issue-33054.rs
index 112d632971a5f..1e644bb973987 100644
--- a/src/test/rustdoc/duplicate_impls/issue-33054.rs
+++ b/src/test/rustdoc/duplicate_impls/issue-33054.rs
@@ -1,8 +1,8 @@
 // @has issue_33054/impls/struct.Foo.html
 // @has - '//code' 'impl Foo'
 // @has - '//code' 'impl Bar for Foo'
-// @count - '//*[@id="trait-implementations-list"]/*[@class="impl"]' 1
-// @count - '//*[@id="main"]/*[@class="impl"]' 1
+// @count - '//*[@id="trait-implementations-list"]//*[@class="impl"]' 1
+// @count - '//*[@id="main"]/details/summary/*[@class="impl"]' 1
 // @has issue_33054/impls/bar/trait.Bar.html
 // @has - '//code' 'impl Bar for Foo'
 // @count - '//*[@class="struct"]' 1
diff --git a/src/test/rustdoc/issue-21474.rs b/src/test/rustdoc/issue-21474.rs
index 896fc1a78f13f..5de26abace6fa 100644
--- a/src/test/rustdoc/issue-21474.rs
+++ b/src/test/rustdoc/issue-21474.rs
@@ -7,5 +7,5 @@ mod inner {
 pub trait Blah { }
 
 // @count issue_21474/struct.What.html \
-//        '//*[@id="trait-implementations-list"]/*[@class="impl"]' 1
+//        '//*[@id="trait-implementations-list"]//*[@class="impl"]' 1
 pub struct What;
diff --git a/src/test/rustdoc/issue-29503.rs b/src/test/rustdoc/issue-29503.rs
index 19bab394dcf20..2b25da77d7e7b 100644
--- a/src/test/rustdoc/issue-29503.rs
+++ b/src/test/rustdoc/issue-29503.rs
@@ -5,7 +5,7 @@ pub trait MyTrait {
     fn my_string(&self) -> String;
 }
 
-// @has - "//div[@id='implementors-list']/h3[@id='impl-MyTrait']//code" "impl<T> MyTrait for T where T: Debug"
+// @has - "//div[@id='implementors-list']//h3[@id='impl-MyTrait']//code" "impl<T> MyTrait for T where T: Debug"
 impl<T> MyTrait for T where T: fmt::Debug {
     fn my_string(&self) -> String {
         format!("{:?}", self)
diff --git a/src/test/rustdoc/issue-45584.rs b/src/test/rustdoc/issue-45584.rs
index 0225c0c5c2fa7..8a5f0413826a9 100644
--- a/src/test/rustdoc/issue-45584.rs
+++ b/src/test/rustdoc/issue-45584.rs
@@ -4,12 +4,12 @@ pub trait Bar<T, U> {}
 
 // @has 'foo/struct.Foo1.html'
 pub struct Foo1;
-// @count - '//*[@id="trait-implementations-list"]/*[@class="impl"]' 1
+// @count - '//*[@id="trait-implementations-list"]//*[@class="impl"]' 1
 // @has - '//*[@class="impl"]' "impl Bar<Foo1, &'static Foo1> for Foo1"
 impl Bar<Foo1, &'static Foo1> for Foo1 {}
 
 // @has 'foo/struct.Foo2.html'
 pub struct Foo2;
-// @count - '//*[@id="trait-implementations-list"]/*[@class="impl"]' 1
+// @count - '//*[@id="trait-implementations-list"]//*[@class="impl"]' 1
 // @has - '//*[@class="impl"]' "impl Bar<&'static Foo2, Foo2> for u8"
 impl Bar<&'static Foo2, Foo2> for u8 {}
diff --git a/src/test/rustdoc/issue-50159.rs b/src/test/rustdoc/issue-50159.rs
index 74502be622a4f..0820512e52140 100644
--- a/src/test/rustdoc/issue-50159.rs
+++ b/src/test/rustdoc/issue-50159.rs
@@ -13,8 +13,8 @@ impl<B, C> Signal2 for B where B: Signal<Item = C> {
 // @has issue_50159/struct.Switch.html
 // @has - '//code' 'impl<B> Send for Switch<B> where <B as Signal>::Item: Send'
 // @has - '//code' 'impl<B> Sync for Switch<B> where <B as Signal>::Item: Sync'
-// @count - '//*[@id="implementations-list"]/*[@class="impl"]' 0
-// @count - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]' 5
+// @count - '//*[@id="implementations-list"]//*[@class="impl"]' 0
+// @count - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]' 5
 pub struct Switch<B: Signal> {
     pub inner: <B as Signal2>::Item2,
 }
diff --git a/src/test/rustdoc/issue-51236.rs b/src/test/rustdoc/issue-51236.rs
index d9accf9c5998b..d018c948162d9 100644
--- a/src/test/rustdoc/issue-51236.rs
+++ b/src/test/rustdoc/issue-51236.rs
@@ -7,7 +7,7 @@ pub mod traits {
 }
 
 // @has issue_51236/struct.Owned.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<T> Send for \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' "impl<T> Send for \
 // Owned<T> where <T as Owned<'static>>::Reader: Send"
 pub struct Owned<T> where T: for<'a> ::traits::Owned<'a> {
     marker: PhantomData<<T as ::traits::Owned<'static>>::Reader>,
diff --git a/src/test/rustdoc/issue-53812.rs b/src/test/rustdoc/issue-53812.rs
index 3ebf154077f49..daebe059f8ef6 100644
--- a/src/test/rustdoc/issue-53812.rs
+++ b/src/test/rustdoc/issue-53812.rs
@@ -12,9 +12,9 @@ macro_rules! array_impls {
     }
 }
 
-// @has issue_53812/trait.MyIterator.html '//*[@id="implementors-list"]//h3[1]' 'MyStruct<[T; 0]>'
-// @has - '//*[@id="implementors-list"]//h3[2]' 'MyStruct<[T; 1]>'
-// @has - '//*[@id="implementors-list"]//h3[3]' 'MyStruct<[T; 2]>'
-// @has - '//*[@id="implementors-list"]//h3[4]' 'MyStruct<[T; 3]>'
-// @has - '//*[@id="implementors-list"]//h3[5]' 'MyStruct<[T; 10]>'
+// @has issue_53812/trait.MyIterator.html '//*[@id="implementors-list"]/details[1]/summary/h3' 'MyStruct<[T; 0]>'
+// @has - '//*[@id="implementors-list"]/details[2]/summary/h3' 'MyStruct<[T; 1]>'
+// @has - '//*[@id="implementors-list"]/details[3]/summary/h3' 'MyStruct<[T; 2]>'
+// @has - '//*[@id="implementors-list"]/details[4]/summary/h3' 'MyStruct<[T; 3]>'
+// @has - '//*[@id="implementors-list"]/details[5]/summary/h3' 'MyStruct<[T; 10]>'
 array_impls! { 10 3 2 1 0 }
diff --git a/src/test/rustdoc/issue-54705.rs b/src/test/rustdoc/issue-54705.rs
index 263b1eb0bd65a..47da94a4ccf4c 100644
--- a/src/test/rustdoc/issue-54705.rs
+++ b/src/test/rustdoc/issue-54705.rs
@@ -3,10 +3,10 @@ pub trait ScopeHandle<'scope> {}
 
 
 // @has issue_54705/struct.ScopeFutureContents.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<'scope, S> \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' "impl<'scope, S> \
 // Send for ScopeFutureContents<'scope, S> where S: Sync"
 //
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<'scope, S> \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' "impl<'scope, S> \
 // Sync for ScopeFutureContents<'scope, S> where S: Sync"
 pub struct ScopeFutureContents<'scope, S>
     where S: ScopeHandle<'scope>,
diff --git a/src/test/rustdoc/issue-55321.rs b/src/test/rustdoc/issue-55321.rs
index d312a5114595a..d1877f39ba761 100644
--- a/src/test/rustdoc/issue-55321.rs
+++ b/src/test/rustdoc/issue-55321.rs
@@ -1,16 +1,16 @@
 #![feature(negative_impls)]
 
 // @has issue_55321/struct.A.html
-// @has - '//*[@id="trait-implementations-list"]/*[@class="impl"]//code' "impl !Send for A"
-// @has - '//*[@id="trait-implementations-list"]/*[@class="impl"]//code' "impl !Sync for A"
+// @has - '//*[@id="trait-implementations-list"]//*[@class="impl"]//code' "impl !Send for A"
+// @has - '//*[@id="trait-implementations-list"]//*[@class="impl"]//code' "impl !Sync for A"
 pub struct A();
 
 impl !Send for A {}
 impl !Sync for A {}
 
 // @has issue_55321/struct.B.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<T> !Send for \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' "impl<T> !Send for \
 // B<T>"
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<T> !Sync for \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' "impl<T> !Sync for \
 // B<T>"
 pub struct B<T: ?Sized>(A, Box<T>);
diff --git a/src/test/rustdoc/issue-56822.rs b/src/test/rustdoc/issue-56822.rs
index 5b67817fa4caa..b932a3d34749c 100644
--- a/src/test/rustdoc/issue-56822.rs
+++ b/src/test/rustdoc/issue-56822.rs
@@ -17,7 +17,7 @@ impl<'a, T> MyTrait for Inner<'a, T> {
 }
 
 // @has issue_56822/struct.Parser.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<'a> Send for \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' "impl<'a> Send for \
 // Parser<'a>"
 pub struct Parser<'a> {
     field: <Wrapper<Inner<'a, u8>> as MyTrait>::Output
diff --git a/src/test/rustdoc/issue-60726.rs b/src/test/rustdoc/issue-60726.rs
index 6acc86277385d..79b8b70c54525 100644
--- a/src/test/rustdoc/issue-60726.rs
+++ b/src/test/rustdoc/issue-60726.rs
@@ -26,9 +26,9 @@ where
 {}
 
 // @has issue_60726/struct.IntoIter.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<T> !Send for \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' "impl<T> !Send for \
 // IntoIter<T>"
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<T> !Sync for \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' "impl<T> !Sync for \
 // IntoIter<T>"
 pub struct IntoIter<T>{
     hello:DynTrait<FooInterface<T>>,
diff --git a/src/test/rustdoc/synthetic_auto/basic.rs b/src/test/rustdoc/synthetic_auto/basic.rs
index 38de5316b6cf5..0dd3a3f7a86c5 100644
--- a/src/test/rustdoc/synthetic_auto/basic.rs
+++ b/src/test/rustdoc/synthetic_auto/basic.rs
@@ -1,8 +1,8 @@
 // @has basic/struct.Foo.html
 // @has - '//code' 'impl<T> Send for Foo<T> where T: Send'
 // @has - '//code' 'impl<T> Sync for Foo<T> where T: Sync'
-// @count - '//*[@id="implementations-list"]/*[@class="impl"]' 0
-// @count - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]' 5
+// @count - '//*[@id="implementations-list"]//*[@class="impl"]' 0
+// @count - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]' 5
 pub struct Foo<T> {
     field: T,
 }
diff --git a/src/test/rustdoc/synthetic_auto/complex.rs b/src/test/rustdoc/synthetic_auto/complex.rs
index 80a717718c22b..d951a20e2dec0 100644
--- a/src/test/rustdoc/synthetic_auto/complex.rs
+++ b/src/test/rustdoc/synthetic_auto/complex.rs
@@ -20,7 +20,7 @@ mod foo {
 }
 
 // @has complex/struct.NotOuter.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<'a, T, K: \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' "impl<'a, T, K: \
 // ?Sized> Send for Outer<'a, T, K> where K: for<'b> Fn((&'b bool, &'a u8)) \
 // -> &'b i8, T: MyTrait<'a>, <T as MyTrait<'a>>::MyItem: Copy, 'a: 'static"
 
diff --git a/src/test/rustdoc/synthetic_auto/lifetimes.rs b/src/test/rustdoc/synthetic_auto/lifetimes.rs
index 6d0a68f9b0734..05c88f10822ca 100644
--- a/src/test/rustdoc/synthetic_auto/lifetimes.rs
+++ b/src/test/rustdoc/synthetic_auto/lifetimes.rs
@@ -9,10 +9,10 @@ where
 {}
 
 // @has lifetimes/struct.Foo.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<'c, K> Send \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' "impl<'c, K> Send \
 // for Foo<'c, K> where K: for<'b> Fn(&'b bool) -> &'c u8, 'c: 'static"
 //
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<'c, K> Sync \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' "impl<'c, K> Sync \
 // for Foo<'c, K> where K: Sync"
 pub struct Foo<'c, K: 'c> {
     inner_field: Inner<'c, K>,
diff --git a/src/test/rustdoc/synthetic_auto/manual.rs b/src/test/rustdoc/synthetic_auto/manual.rs
index d20b4744af15b..88ddd57349a29 100644
--- a/src/test/rustdoc/synthetic_auto/manual.rs
+++ b/src/test/rustdoc/synthetic_auto/manual.rs
@@ -1,12 +1,12 @@
 // @has manual/struct.Foo.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' 'impl<T> Sync for \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' 'impl<T> Sync for \
 // Foo<T> where T: Sync'
 //
-// @has - '//*[@id="trait-implementations-list"]/*[@class="impl"]//code' \
+// @has - '//*[@id="trait-implementations-list"]//*[@class="impl"]//code' \
 // 'impl<T> Send for Foo<T>'
 //
-// @count - '//*[@id="trait-implementations-list"]/*[@class="impl"]' 1
-// @count - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]' 4
+// @count - '//*[@id="trait-implementations-list"]//*[@class="impl"]' 1
+// @count - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]' 4
 pub struct Foo<T> {
     field: T,
 }
diff --git a/src/test/rustdoc/synthetic_auto/negative.rs b/src/test/rustdoc/synthetic_auto/negative.rs
index 30713849da221..53801542c9520 100644
--- a/src/test/rustdoc/synthetic_auto/negative.rs
+++ b/src/test/rustdoc/synthetic_auto/negative.rs
@@ -3,10 +3,10 @@ pub struct Inner<T: Copy> {
 }
 
 // @has negative/struct.Outer.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<T> !Send for \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' "impl<T> !Send for \
 // Outer<T>"
 //
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<T> \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' "impl<T> \
 // !Sync for Outer<T>"
 pub struct Outer<T: Copy> {
     inner_field: Inner<T>,
diff --git a/src/test/rustdoc/synthetic_auto/nested.rs b/src/test/rustdoc/synthetic_auto/nested.rs
index e710ce1c2ed95..d4d93a87ffc9b 100644
--- a/src/test/rustdoc/synthetic_auto/nested.rs
+++ b/src/test/rustdoc/synthetic_auto/nested.rs
@@ -9,10 +9,10 @@ where
 }
 
 // @has nested/struct.Foo.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' 'impl<T> Send for \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' 'impl<T> Send for \
 // Foo<T> where T: Copy'
 //
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' \
 // 'impl<T> Sync for Foo<T> where T: Sync'
 pub struct Foo<T> {
     inner_field: Inner<T>,
diff --git a/src/test/rustdoc/synthetic_auto/no-redundancy.rs b/src/test/rustdoc/synthetic_auto/no-redundancy.rs
index cf173111ec1e2..3a23dc2cf9576 100644
--- a/src/test/rustdoc/synthetic_auto/no-redundancy.rs
+++ b/src/test/rustdoc/synthetic_auto/no-redundancy.rs
@@ -9,7 +9,7 @@ where
 }
 
 // @has no_redundancy/struct.Outer.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<T> Send for \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' "impl<T> Send for \
 // Outer<T> where T: Copy + Send"
 pub struct Outer<T> {
     inner_field: Inner<T>,
diff --git a/src/test/rustdoc/synthetic_auto/project.rs b/src/test/rustdoc/synthetic_auto/project.rs
index 5346521f8d2e3..060491e3cf10f 100644
--- a/src/test/rustdoc/synthetic_auto/project.rs
+++ b/src/test/rustdoc/synthetic_auto/project.rs
@@ -23,10 +23,10 @@ where
 }
 
 // @has project/struct.Foo.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<'c, K> Send \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' "impl<'c, K> Send \
 // for Foo<'c, K> where K: MyTrait<MyItem = bool>, 'c: 'static"
 //
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<'c, K> Sync \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' "impl<'c, K> Sync \
 // for Foo<'c, K> where K: MyTrait, <K as MyTrait>::MyItem: OtherTrait, 'c: 'static,"
 pub struct Foo<'c, K: 'c> {
     inner_field: Inner<'c, K>,
diff --git a/src/test/rustdoc/synthetic_auto/self-referential.rs b/src/test/rustdoc/synthetic_auto/self-referential.rs
index 905aa20918bef..ecdbdf41b2025 100644
--- a/src/test/rustdoc/synthetic_auto/self-referential.rs
+++ b/src/test/rustdoc/synthetic_auto/self-referential.rs
@@ -23,7 +23,7 @@ impl<T> Pattern for Wrapper<T> {
 
 
 // @has self_referential/struct.WriteAndThen.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<P1> Send for \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' "impl<P1> Send for \
 // WriteAndThen<P1>  where  <P1 as Pattern>::Value: Send"
 pub struct WriteAndThen<P1>(pub P1::Value,pub <Constrain<P1, Wrapper<P1::Value>> as Pattern>::Value)
     where P1: Pattern;
diff --git a/src/test/rustdoc/synthetic_auto/static-region.rs b/src/test/rustdoc/synthetic_auto/static-region.rs
index 59493744b623d..a10e694c1b281 100644
--- a/src/test/rustdoc/synthetic_auto/static-region.rs
+++ b/src/test/rustdoc/synthetic_auto/static-region.rs
@@ -3,7 +3,7 @@ pub trait OwnedTrait<'a> {
 }
 
 // @has static_region/struct.Owned.html
-// @has - '//*[@id="synthetic-implementations-list"]/*[@class="impl"]//code' "impl<T> Send for \
+// @has - '//*[@id="synthetic-implementations-list"]//*[@class="impl"]//code' "impl<T> Send for \
 // Owned<T> where <T as OwnedTrait<'static>>::Reader: Send"
 pub struct Owned<T> where T: OwnedTrait<'static> {
     marker: <T as OwnedTrait<'static>>::Reader,
diff --git a/src/test/ui/associated-type-bounds/issue-81193.rs b/src/test/ui/associated-type-bounds/issue-81193.rs
new file mode 100644
index 0000000000000..d2aa54ab9512e
--- /dev/null
+++ b/src/test/ui/associated-type-bounds/issue-81193.rs
@@ -0,0 +1,15 @@
+// check-pass
+
+#![feature(associated_type_bounds)]
+
+trait A<'a, 'b> {}
+
+trait B<'a, 'b, 'c> {}
+
+fn err<'u, 'a, F>()
+where
+    for<'b> F: Iterator<Item: for<'c> B<'a, 'b, 'c> + for<'c> A<'a, 'c>>,
+{
+}
+
+fn main() {}
diff --git a/src/test/ui/associated-type-bounds/issue-83017.rs b/src/test/ui/associated-type-bounds/issue-83017.rs
new file mode 100644
index 0000000000000..8f0a9ea3566fb
--- /dev/null
+++ b/src/test/ui/associated-type-bounds/issue-83017.rs
@@ -0,0 +1,39 @@
+#![feature(associated_type_bounds)]
+
+trait TraitA<'a> {
+    type AsA;
+}
+
+trait TraitB<'a, 'b> {
+    type AsB;
+}
+
+trait TraitC<'a, 'b, 'c> {}
+
+struct X;
+
+impl<'a, 'b, 'c> TraitC<'a, 'b, 'c> for X {}
+
+struct Y;
+
+impl<'a, 'b> TraitB<'a, 'b> for Y {
+    type AsB = X;
+}
+
+struct Z;
+
+impl<'a> TraitA<'a> for Z {
+    type AsA = Y;
+}
+
+fn foo<T>()
+where
+    for<'a> T: TraitA<'a, AsA: for<'b> TraitB<'a, 'b, AsB: for<'c> TraitC<'a, 'b, 'c>>>,
+{
+}
+
+fn main() {
+    foo::<Z>();
+    //~^ ERROR: the trait bound `for<'a, 'b> <Z as TraitA<'a>>::AsA: TraitB<'a, 'b>` is not satisfied
+    //~| ERROR: the trait bound `for<'a, 'b, 'c> <<Z as TraitA<'a>>::AsA as TraitB<'a, 'b>>::AsB: TraitC<'a, 'b, 'c>` is not satisfied
+}
diff --git a/src/test/ui/associated-type-bounds/issue-83017.stderr b/src/test/ui/associated-type-bounds/issue-83017.stderr
new file mode 100644
index 0000000000000..4eb71fd0287e0
--- /dev/null
+++ b/src/test/ui/associated-type-bounds/issue-83017.stderr
@@ -0,0 +1,27 @@
+error[E0277]: the trait bound `for<'a, 'b> <Z as TraitA<'a>>::AsA: TraitB<'a, 'b>` is not satisfied
+  --> $DIR/issue-83017.rs:36:5
+   |
+LL | fn foo<T>()
+   |    --- required by a bound in this
+LL | where
+LL |     for<'a> T: TraitA<'a, AsA: for<'b> TraitB<'a, 'b, AsB: for<'c> TraitC<'a, 'b, 'c>>>,
+   |                                ------------------------------------------------------- required by this bound in `foo`
+...
+LL |     foo::<Z>();
+   |     ^^^^^^^^ the trait `for<'a, 'b> TraitB<'a, 'b>` is not implemented for `<Z as TraitA<'a>>::AsA`
+
+error[E0277]: the trait bound `for<'a, 'b, 'c> <<Z as TraitA<'a>>::AsA as TraitB<'a, 'b>>::AsB: TraitC<'a, 'b, 'c>` is not satisfied
+  --> $DIR/issue-83017.rs:36:5
+   |
+LL | fn foo<T>()
+   |    --- required by a bound in this
+LL | where
+LL |     for<'a> T: TraitA<'a, AsA: for<'b> TraitB<'a, 'b, AsB: for<'c> TraitC<'a, 'b, 'c>>>,
+   |                                                            -------------------------- required by this bound in `foo`
+...
+LL |     foo::<Z>();
+   |     ^^^^^^^^ the trait `for<'a, 'b, 'c> TraitC<'a, 'b, 'c>` is not implemented for `<<Z as TraitA<'a>>::AsA as TraitB<'a, 'b>>::AsB`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/specialization/issue-33017.rs b/src/test/ui/specialization/issue-33017.rs
new file mode 100644
index 0000000000000..4d19230df6bad
--- /dev/null
+++ b/src/test/ui/specialization/issue-33017.rs
@@ -0,0 +1,45 @@
+// Test to ensure that trait bounds are propertly
+// checked on specializable associated types
+
+#![allow(incomplete_features)]
+#![feature(specialization)]
+
+trait UncheckedCopy: Sized {
+    type Output: From<Self> + Copy + Into<Self>;
+}
+
+impl<T> UncheckedCopy for T {
+    default type Output = Self;
+    //~^ ERROR: the trait bound `T: Copy` is not satisfied
+}
+
+fn unchecked_copy<T: UncheckedCopy>(other: &T::Output) -> T {
+    (*other).into()
+}
+
+fn bug(origin: String) {
+    // Turn the String into it's Output type...
+    // Which we can just do by `.into()`, the assoc type states `From<Self>`.
+    let origin_output = origin.into();
+
+    // Make a copy of String::Output, which is a String...
+    let mut copy: String = unchecked_copy::<String>(&origin_output);
+
+    // Turn the Output type into a String again,
+    // Which we can just do by `.into()`, the assoc type states `Into<Self>`.
+    let mut origin: String = origin_output.into();
+
+    // assert both Strings use the same buffer.
+    assert_eq!(copy.as_ptr(), origin.as_ptr());
+
+    // Any use of the copy we made becomes invalid,
+    drop(origin);
+
+    // OH NO! UB UB UB UB!
+    copy.push_str(" world!");
+    println!("{}", copy);
+}
+
+fn main() {
+    bug(String::from("hello"));
+}
diff --git a/src/test/ui/specialization/issue-33017.stderr b/src/test/ui/specialization/issue-33017.stderr
new file mode 100644
index 0000000000000..bff4618d0be4c
--- /dev/null
+++ b/src/test/ui/specialization/issue-33017.stderr
@@ -0,0 +1,17 @@
+error[E0277]: the trait bound `T: Copy` is not satisfied
+  --> $DIR/issue-33017.rs:12:5
+   |
+LL |     type Output: From<Self> + Copy + Into<Self>;
+   |                               ---- required by this bound in `UncheckedCopy::Output`
+...
+LL |     default type Output = Self;
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `T`
+   |
+help: consider restricting type parameter `T`
+   |
+LL | impl<T: std::marker::Copy> UncheckedCopy for T {
+   |       ^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/specialization/issue-51892.rs b/src/test/ui/specialization/issue-51892.rs
new file mode 100644
index 0000000000000..3cd0711ae42c6
--- /dev/null
+++ b/src/test/ui/specialization/issue-51892.rs
@@ -0,0 +1,19 @@
+#![allow(incomplete_features)]
+#![feature(const_generics)]
+#![feature(const_evaluatable_checked)]
+#![feature(specialization)]
+
+pub trait Trait {
+    type Type;
+}
+
+impl<T: ?Sized> Trait for T {
+    default type Type = [u8; 1];
+}
+
+impl<T: Trait> Trait for *const T {
+    type Type = [u8; std::mem::size_of::<<T as Trait>::Type>()];
+    //~^ ERROR: unconstrained generic constant
+}
+
+fn main() {}
diff --git a/src/test/ui/specialization/issue-51892.stderr b/src/test/ui/specialization/issue-51892.stderr
new file mode 100644
index 0000000000000..2d30164380a8e
--- /dev/null
+++ b/src/test/ui/specialization/issue-51892.stderr
@@ -0,0 +1,10 @@
+error: unconstrained generic constant
+  --> $DIR/issue-51892.rs:15:5
+   |
+LL |     type Type = [u8; std::mem::size_of::<<T as Trait>::Type>()];
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: try adding a `where` bound using this expression: `where [(); std::mem::size_of::<<T as Trait>::Type>()]:`
+
+error: aborting due to previous error
+