From 3ae5fed04c94be2f8591c7f4ab76f78ec882cd32 Mon Sep 17 00:00:00 2001
From: Jack Huey <jack.huey@umassmed.edu>
Date: Tue, 6 Apr 2021 15:34:29 -0400
Subject: [PATCH 01/21] Fix a couple resolve bugs from binder refactor

---
 compiler/rustc_resolve/src/late/lifetimes.rs    | 16 +++++++++++++++-
 ...3-invalid-associated-type-supertrait-hrtb.rs |  8 ++++++++
 ...valid-associated-type-supertrait-hrtb.stderr |  9 +++++++++
 .../issue-83907-invalid-fn-like-path.rs         |  7 +++++++
 .../issue-83907-invalid-fn-like-path.stderr     | 17 +++++++++++++++++
 5 files changed, 56 insertions(+), 1 deletion(-)
 create mode 100644 src/test/ui/lifetimes/issue-83753-invalid-associated-type-supertrait-hrtb.rs
 create mode 100644 src/test/ui/lifetimes/issue-83753-invalid-associated-type-supertrait-hrtb.stderr
 create mode 100644 src/test/ui/lifetimes/issue-83907-invalid-fn-like-path.rs
 create mode 100644 src/test/ui/lifetimes/issue-83907-invalid-fn-like-path.stderr

diff --git a/compiler/rustc_resolve/src/late/lifetimes.rs b/compiler/rustc_resolve/src/late/lifetimes.rs
index b89ad867f46..70ddfcc9004 100644
--- a/compiler/rustc_resolve/src/late/lifetimes.rs
+++ b/compiler/rustc_resolve/src/late/lifetimes.rs
@@ -2659,6 +2659,13 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
                 Some(next) => next,
                 None => break None,
             };
+            // See issue #83753. If someone writes an associated type on a non-trait, just treat it as
+            // there being no supertrait HRTBs.
+            match tcx.def_kind(def_id) {
+                DefKind::Trait | DefKind::TraitAlias | DefKind::Impl => {}
+                _ => break None,
+            }
+
             if trait_defines_associated_type_named(def_id) {
                 break Some(bound_vars.into_iter().collect());
             }
@@ -2703,7 +2710,14 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
                 | Scope::Supertrait { ref s, .. } => {
                     scope = *s;
                 }
-                Scope::Root => bug!("In fn_like_elision without appropriate scope above"),
+                Scope::Root => {
+                    // See issue #83907. Just bail out from looking inside.
+                    self.tcx.sess.delay_span_bug(
+                        rustc_span::DUMMY_SP,
+                        "In fn_like_elision without appropriate scope above",
+                    );
+                    return;
+                }
             }
         };
         // While not strictly necessary, we gather anon lifetimes *before* actually
diff --git a/src/test/ui/lifetimes/issue-83753-invalid-associated-type-supertrait-hrtb.rs b/src/test/ui/lifetimes/issue-83753-invalid-associated-type-supertrait-hrtb.rs
new file mode 100644
index 00000000000..7f0ea730dd3
--- /dev/null
+++ b/src/test/ui/lifetimes/issue-83753-invalid-associated-type-supertrait-hrtb.rs
@@ -0,0 +1,8 @@
+// check-fail
+
+struct Foo {}
+impl Foo {
+    fn bar(foo: Foo<Target = usize>) {}
+    //~^ associated type bindings are not allowed here
+}
+fn main() {}
diff --git a/src/test/ui/lifetimes/issue-83753-invalid-associated-type-supertrait-hrtb.stderr b/src/test/ui/lifetimes/issue-83753-invalid-associated-type-supertrait-hrtb.stderr
new file mode 100644
index 00000000000..f7bdee6336e
--- /dev/null
+++ b/src/test/ui/lifetimes/issue-83753-invalid-associated-type-supertrait-hrtb.stderr
@@ -0,0 +1,9 @@
+error[E0229]: associated type bindings are not allowed here
+  --> $DIR/issue-83753-invalid-associated-type-supertrait-hrtb.rs:5:21
+   |
+LL |     fn bar(foo: Foo<Target = usize>) {}
+   |                     ^^^^^^^^^^^^^^ associated type not allowed here
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0229`.
diff --git a/src/test/ui/lifetimes/issue-83907-invalid-fn-like-path.rs b/src/test/ui/lifetimes/issue-83907-invalid-fn-like-path.rs
new file mode 100644
index 00000000000..604687ce711
--- /dev/null
+++ b/src/test/ui/lifetimes/issue-83907-invalid-fn-like-path.rs
@@ -0,0 +1,7 @@
+// check-fail
+
+static STATIC_VAR_FIVE: &One();
+//~^ cannot find type
+//~| free static item without body
+
+fn main() {}
diff --git a/src/test/ui/lifetimes/issue-83907-invalid-fn-like-path.stderr b/src/test/ui/lifetimes/issue-83907-invalid-fn-like-path.stderr
new file mode 100644
index 00000000000..e57933da558
--- /dev/null
+++ b/src/test/ui/lifetimes/issue-83907-invalid-fn-like-path.stderr
@@ -0,0 +1,17 @@
+error: free static item without body
+  --> $DIR/issue-83907-invalid-fn-like-path.rs:3:1
+   |
+LL | static STATIC_VAR_FIVE: &One();
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-
+   |                               |
+   |                               help: provide a definition for the static: `= <expr>;`
+
+error[E0412]: cannot find type `One` in this scope
+  --> $DIR/issue-83907-invalid-fn-like-path.rs:3:26
+   |
+LL | static STATIC_VAR_FIVE: &One();
+   |                          ^^^ not found in this scope
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0412`.

From c96f86de3026f864e78397aff9097e885f2f8fdf Mon Sep 17 00:00:00 2001
From: Manish Goregaokar <manishsmail@gmail.com>
Date: Sat, 20 Mar 2021 17:36:19 -0700
Subject: [PATCH 02/21] rustdoc: Stop hiding entire item declarations

---
 src/librustdoc/html/render/mod.rs        | 11 -----------
 src/librustdoc/html/render/print_item.rs |  2 +-
 src/librustdoc/html/static/main.js       | 25 ++++--------------------
 3 files changed, 5 insertions(+), 33 deletions(-)

diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index fbe799e7184..ca754fa347b 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -486,17 +486,6 @@ fn settings(root_path: &str, suffix: &str, themes: &[StylePath]) -> Result<Strin
             ],
         )
             .into(),
-        (
-            "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)
diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index 0cdfe435b9c..6c0c8a01014 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -1171,7 +1171,7 @@ fn wrap_into_docblock<F>(w: &mut Buffer, f: F)
 where
     F: FnOnce(&mut Buffer),
 {
-    w.write_str("<div class=\"docblock type-decl hidden-by-usual-hider\">");
+    w.write_str("<div class=\"docblock type-decl\">");
     f(w);
     w.write_str("</div>")
 }
diff --git a/src/librustdoc/html/static/main.js b/src/librustdoc/html/static/main.js
index 80dc6b923f6..0abfe18a19f 100644
--- a/src/librustdoc/html/static/main.js
+++ b/src/librustdoc/html/static/main.js
@@ -2683,18 +2683,7 @@ function hideThemeButtonState() {
                 });
             }
         }
-        var showItemDeclarations = getSettingValue("auto-hide-" + className);
-        if (showItemDeclarations === null) {
-            if (className === "enum" || className === "macro") {
-                showItemDeclarations = "false";
-            } else if (className === "struct" || className === "union" || className === "trait") {
-                showItemDeclarations = "true";
-            } else {
-                // In case we found an unknown type, we just use the "parent" value.
-                showItemDeclarations = getSettingValue("auto-hide-declarations");
-            }
-        }
-        showItemDeclarations = showItemDeclarations === "false";
+
         function buildToggleWrapper(e) {
             if (hasClass(e, "autohide")) {
                 var wrap = e.previousElementSibling;
@@ -2721,11 +2710,8 @@ function hideThemeButtonState() {
                 var extraClass;
 
                 if (hasClass(e, "type-decl")) {
-                    fontSize = "20px";
-                    otherMessage = "&nbsp;Show&nbsp;declaration";
-                    if (showItemDeclarations === false) {
-                        extraClass = "collapsed";
-                    }
+                    // We do something special for these
+                    return;
                 } else if (hasClass(e, "sub-variant")) {
                     otherMessage = "&nbsp;Show&nbsp;fields";
                 } else if (hasClass(e, "non-exhaustive")) {
@@ -2750,11 +2736,8 @@ function hideThemeButtonState() {
                         otherMessage,
                         fontSize,
                         extraClass,
-                        hasClass(e, "type-decl") === false || showItemDeclarations === true),
+                        false),
                     e);
-                if (hasClass(e, "type-decl") === true && showItemDeclarations === true) {
-                    collapseDocs(e.previousSibling.childNodes[0], "toggle");
-                }
                 if (hasClass(e, "non-exhaustive") === true) {
                     collapseDocs(e.previousSibling.childNodes[0], "toggle");
                 }

From 71c52acf32efb48975edb86a1cef1df810f60c45 Mon Sep 17 00:00:00 2001
From: Manish Goregaokar <manishsmail@gmail.com>
Date: Sat, 20 Mar 2021 19:02:25 -0700
Subject: [PATCH 03/21] rustdoc: hide variants of enums > 5

---
 src/librustdoc/html/render/print_item.rs | 24 ++++++++++++++++++++++++
 src/librustdoc/html/static/main.js       |  4 ++++
 src/librustdoc/html/static/rustdoc.css   | 13 ++++++-------
 3 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index 6c0c8a01014..3b9750a8d63 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -131,6 +131,23 @@ pub(super) fn print_item(cx: &Context<'_>, item: &clean::Item, buf: &mut Buffer)
     }
 }
 
+/// For large structs, enums, unions, etc, determine whether to hide their fields
+fn should_hide_fields(n_fields: usize) -> bool {
+    // todo: figure out what this should be
+    n_fields > 5
+}
+
+fn toggle_open(w: &mut Buffer, text: &str)
+{
+    write!(w, "<div class=\"docblock type-contents-toggle\" data-toggle-text=\"{}\">", text);
+}
+
+fn toggle_close(w: &mut Buffer)
+{
+    w.write_str("</div>");
+}
+
+
 fn item_module(w: &mut Buffer, cx: &Context<'_>, item: &clean::Item, items: &[clean::Item]) {
     document(w, cx, item, None);
 
@@ -816,6 +833,10 @@ fn item_enum(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, e: &clean::Enum
             w.write_str(" {}");
         } else {
             w.write_str(" {\n");
+            let toggle = should_hide_fields(e.variants.len());
+            if toggle {
+                toggle_open(w, "variants");
+            }
             for v in &e.variants {
                 w.write_str("    ");
                 let name = v.name.as_ref().unwrap();
@@ -844,6 +865,9 @@ fn item_enum(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, e: &clean::Enum
             if e.variants_stripped {
                 w.write_str("    // some variants omitted\n");
             }
+            if toggle {
+                toggle_close(w);
+            }
             w.write_str("}");
         }
         w.write_str("</pre>")
diff --git a/src/librustdoc/html/static/main.js b/src/librustdoc/html/static/main.js
index 0abfe18a19f..f112a113adc 100644
--- a/src/librustdoc/html/static/main.js
+++ b/src/librustdoc/html/static/main.js
@@ -2703,6 +2703,10 @@ function hideThemeButtonState() {
                         }
                     });
                 }
+            } else if (hasClass(e, "type-contents-toggle")) {
+                let text = e.getAttribute("data-toggle-text");
+                let tog = createToggle(toggle, `Show ${text}`, null, "", true);
+                e.parentNode.insertBefore(tog,  e);
             }
             if (e.parentNode.id === "main") {
                 var otherMessage = "";
diff --git a/src/librustdoc/html/static/rustdoc.css b/src/librustdoc/html/static/rustdoc.css
index 585b7459bd7..3a171a1d652 100644
--- a/src/librustdoc/html/static/rustdoc.css
+++ b/src/librustdoc/html/static/rustdoc.css
@@ -970,6 +970,10 @@ a.test-arrow:hover{
 	position: absolute;
 	left: -23px;
 	top: 0;
+
+	/* The click event for this is defined on the document,
+	   so bubbling does not work. See https://github.com/rust-lang/rust/issues/83332 */
+	z-index: 10;
 }
 
 h3 > .collapse-toggle, h4 > .collapse-toggle {
@@ -1054,10 +1058,9 @@ h3 > .collapse-toggle, h4 > .collapse-toggle {
 	margin-top: 3px;
 }
 
+/* for enum and struct fields */
 .enum > .toggle-wrapper + .docblock, .struct > .toggle-wrapper + .docblock {
-	margin-left: 30px;
-	margin-bottom: 20px;
-	margin-top: 5px;
+	margin-left: 0px;
 }
 
 .docblock > .section-header:first-child {
@@ -1069,10 +1072,6 @@ h3 > .collapse-toggle, h4 > .collapse-toggle {
 	left: -10px;
 }
 
-.enum > .collapsed, .struct > .collapsed {
-	margin-bottom: 25px;
-}
-
 #main > .variant, #main > .structfield {
 	display: block;
 }

From f146b9701df0e26dad61422089d3a7e9a49989c5 Mon Sep 17 00:00:00 2001
From: Manish Goregaokar <manishsmail@gmail.com>
Date: Sat, 20 Mar 2021 19:11:49 -0700
Subject: [PATCH 04/21] rustdoc: hide fields of structs/unions > 5

---
 src/librustdoc/html/render/print_item.rs | 37 +++++++++++++++++++-----
 src/librustdoc/html/static/rustdoc.css   |  2 +-
 2 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index 3b9750a8d63..b6e9a8e244a 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -137,17 +137,14 @@ fn should_hide_fields(n_fields: usize) -> bool {
     n_fields > 5
 }
 
-fn toggle_open(w: &mut Buffer, text: &str)
-{
+fn toggle_open(w: &mut Buffer, text: &str) {
     write!(w, "<div class=\"docblock type-contents-toggle\" data-toggle-text=\"{}\">", text);
 }
 
-fn toggle_close(w: &mut Buffer)
-{
+fn toggle_close(w: &mut Buffer) {
     w.write_str("</div>");
 }
 
-
 fn item_module(w: &mut Buffer, cx: &Context<'_>, item: &clean::Item, items: &[clean::Item]) {
     document(w, cx, item, None);
 
@@ -1285,6 +1282,17 @@ fn render_union(
     }
 
     write!(w, " {{\n{}", tab);
+    let count_fields = fields
+        .iter()
+        .filter(
+            |f| if let clean::StructFieldItem(..) = *f.kind { true } else { false },
+        )
+        .count();
+    let toggle = should_hide_fields(count_fields);
+    if toggle {
+        toggle_open(w, "fields");
+    }
+
     for field in fields {
         if let clean::StructFieldItem(ref ty) = *field.kind {
             write!(
@@ -1301,6 +1309,9 @@ fn render_union(
     if it.has_stripped_fields().unwrap() {
         write!(w, "    // some fields omitted\n{}", tab);
     }
+    if toggle {
+        toggle_close(w);
+    }
     w.write_str("}");
 }
 
@@ -1329,8 +1340,18 @@ fn render_struct(
             if let Some(g) = g {
                 write!(w, "{}", print_where_clause(g, cx.cache(), cx.tcx(), 0, true),)
             }
-            let mut has_visible_fields = false;
             w.write_str(" {");
+            let count_fields = fields
+                .iter()
+                .filter(
+                    |f| if let clean::StructFieldItem(..) = *f.kind { true } else { false },
+                )
+                .count();
+            let has_visible_fields = count_fields > 0;
+            let toggle = should_hide_fields(count_fields);
+            if toggle {
+                toggle_open(w, "fields");
+            }
             for field in fields {
                 if let clean::StructFieldItem(ref ty) = *field.kind {
                     write!(
@@ -1341,7 +1362,6 @@ fn render_struct(
                         field.name.as_ref().unwrap(),
                         ty.print(cx.cache(), cx.tcx()),
                     );
-                    has_visible_fields = true;
                 }
             }
 
@@ -1355,6 +1375,9 @@ fn render_struct(
                 // `{ /* fields omitted */ }` to save space.
                 write!(w, " /* fields omitted */ ");
             }
+            if toggle {
+                toggle_close(w);
+            }
             w.write_str("}");
         }
         CtorKind::Fn => {
diff --git a/src/librustdoc/html/static/rustdoc.css b/src/librustdoc/html/static/rustdoc.css
index 3a171a1d652..2cdacbe0b06 100644
--- a/src/librustdoc/html/static/rustdoc.css
+++ b/src/librustdoc/html/static/rustdoc.css
@@ -1059,7 +1059,7 @@ h3 > .collapse-toggle, h4 > .collapse-toggle {
 }
 
 /* for enum and struct fields */
-.enum > .toggle-wrapper + .docblock, .struct > .toggle-wrapper + .docblock {
+.enum > .toggle-wrapper + .docblock, .struct > .toggle-wrapper + .docblock, .union > .toggle-wrapper + .docblock {
 	margin-left: 0px;
 }
 

From 173cbecc66ee1bbb54c039a00c3b75b4cdf7e277 Mon Sep 17 00:00:00 2001
From: Manish Goregaokar <manishsmail@gmail.com>
Date: Sat, 20 Mar 2021 19:39:29 -0700
Subject: [PATCH 05/21] rustdoc: smartly hide associated items of traits if
 there are too many of them

---
 src/librustdoc/html/render/print_item.rs    | 30 ++++++++++++++++-----
 src/librustdoc/html/static/rustdoc.css      |  6 ++---
 src/librustdoc/html/static/themes/ayu.css   |  2 +-
 src/librustdoc/html/static/themes/dark.css  |  2 +-
 src/librustdoc/html/static/themes/light.css |  2 +-
 5 files changed, 30 insertions(+), 12 deletions(-)

diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index b6e9a8e244a..8db78e7718d 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -443,10 +443,25 @@ fn item_trait(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Tra
         } else {
             // FIXME: we should be using a derived_id for the Anchors here
             w.write_str("{\n");
+            let mut toggle = false;
+
+            // If there are too many associated types, hide _everything_
+            if should_hide_fields(types.len()) {
+                toggle = true;
+                toggle_open(w, "associated items");
+            }
             for t in &types {
                 render_assoc_item(w, t, AssocItemLink::Anchor(None), ItemType::Trait, cx);
                 w.write_str(";\n");
             }
+            // If there are too many associated constants, hide everything after them
+            // We also do this if the types + consts is large because otherwise we could
+            // render a bunch of types and _then_ a bunch of consts just because both were
+            // _just_ under the limit
+            if !toggle & should_hide_fields(types.len() + consts.len()) {
+                toggle = true;
+                toggle_open(w, "associated constants and methods");
+            }
             if !types.is_empty() && !consts.is_empty() {
                 w.write_str("\n");
             }
@@ -454,6 +469,10 @@ fn item_trait(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Tra
                 render_assoc_item(w, t, AssocItemLink::Anchor(None), ItemType::Trait, cx);
                 w.write_str(";\n");
             }
+            if !toggle & should_hide_fields(required.len() + provided.len()) {
+                toggle = true;
+                toggle_open(w, "methods");
+            }
             if !consts.is_empty() && !required.is_empty() {
                 w.write_str("\n");
             }
@@ -484,6 +503,9 @@ fn item_trait(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Tra
                     w.write_str("<div class=\"item-spacer\"></div>");
                 }
             }
+            if toggle {
+                toggle_close(w);
+            }
             w.write_str("}");
         }
         w.write_str("</pre>")
@@ -1284,9 +1306,7 @@ fn render_union(
     write!(w, " {{\n{}", tab);
     let count_fields = fields
         .iter()
-        .filter(
-            |f| if let clean::StructFieldItem(..) = *f.kind { true } else { false },
-        )
+        .filter(|f| if let clean::StructFieldItem(..) = *f.kind { true } else { false })
         .count();
     let toggle = should_hide_fields(count_fields);
     if toggle {
@@ -1343,9 +1363,7 @@ fn render_struct(
             w.write_str(" {");
             let count_fields = fields
                 .iter()
-                .filter(
-                    |f| if let clean::StructFieldItem(..) = *f.kind { true } else { false },
-                )
+                .filter(|f| if let clean::StructFieldItem(..) = *f.kind { true } else { false })
                 .count();
             let has_visible_fields = count_fields > 0;
             let toggle = should_hide_fields(count_fields);
diff --git a/src/librustdoc/html/static/rustdoc.css b/src/librustdoc/html/static/rustdoc.css
index 2cdacbe0b06..309e55670b1 100644
--- a/src/librustdoc/html/static/rustdoc.css
+++ b/src/librustdoc/html/static/rustdoc.css
@@ -1058,8 +1058,8 @@ h3 > .collapse-toggle, h4 > .collapse-toggle {
 	margin-top: 3px;
 }
 
-/* for enum and struct fields */
-.enum > .toggle-wrapper + .docblock, .struct > .toggle-wrapper + .docblock, .union > .toggle-wrapper + .docblock {
+/* for hiding fields/variants/associated items */
+.enum > .toggle-wrapper + .docblock, .struct > .toggle-wrapper + .docblock, .union > .toggle-wrapper + .docblock, .trait > .toggle-wrapper + .docblock {
 	margin-left: 0px;
 }
 
@@ -1785,7 +1785,7 @@ div.name.expand::before {
 .type-decl > pre > .docblock.attributes.top-attr {
 	margin-left: 1.8em !important;
 }
-.type-decl > pre > .toggle-attributes {
+.type-decl > pre .toggle-attributes {
 	margin-left: 2.2em;
 }
 .type-decl > pre > .docblock.attributes {
diff --git a/src/librustdoc/html/static/themes/ayu.css b/src/librustdoc/html/static/themes/ayu.css
index b24f4035ca8..0404fa50b99 100644
--- a/src/librustdoc/html/static/themes/ayu.css
+++ b/src/librustdoc/html/static/themes/ayu.css
@@ -218,7 +218,7 @@ a {
 	color: #c5c5c5;
 }
 
-.docblock:not(.type-decl) a:not(.srclink):not(.test-arrow),
+.docblock:not(.type-decl) a:not(.srclink):not(.test-arrow):not(.collapse-toggle),
 .docblock-short a:not(.srclink):not(.test-arrow), .item-info a,
 #help a {
 	color: #39AFD7;
diff --git a/src/librustdoc/html/static/themes/dark.css b/src/librustdoc/html/static/themes/dark.css
index e863ed03f51..15b485a966f 100644
--- a/src/librustdoc/html/static/themes/dark.css
+++ b/src/librustdoc/html/static/themes/dark.css
@@ -176,7 +176,7 @@ a {
 	color: #ddd;
 }
 
-.docblock:not(.type-decl) a:not(.srclink):not(.test-arrow),
+.docblock:not(.type-decl) a:not(.srclink):not(.test-arrow):not(.collapse-toggle),
 .docblock-short a:not(.srclink):not(.test-arrow), .item-info a,
 #help a {
 	color: #D2991D;
diff --git a/src/librustdoc/html/static/themes/light.css b/src/librustdoc/html/static/themes/light.css
index 9335dd96d29..4c83879e234 100644
--- a/src/librustdoc/html/static/themes/light.css
+++ b/src/librustdoc/html/static/themes/light.css
@@ -174,7 +174,7 @@ a {
 	color: #000;
 }
 
-.docblock:not(.type-decl) a:not(.srclink):not(.test-arrow),
+.docblock:not(.type-decl) a:not(.srclink):not(.test-arrow):not(.collapse-toggle),
 .docblock-short a:not(.srclink):not(.test-arrow), .item-info a,
 #help a {
 	color: #3873AD;

From 256e594b0a75ddc792adb35e3810d29133ee0f79 Mon Sep 17 00:00:00 2001
From: Manish Goregaokar <manishsmail@gmail.com>
Date: Sat, 20 Mar 2021 19:44:55 -0700
Subject: [PATCH 06/21] rustdoc: Add setting for hiding large items

---
 src/librustdoc/html/render/mod.rs  | 1 +
 src/librustdoc/html/static/main.js | 6 +++++-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index ca754fa347b..00a19006bb9 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -486,6 +486,7 @@ fn settings(root_path: &str, suffix: &str, themes: &[StylePath]) -> Result<Strin
             ],
         )
             .into(),
+        ("auto-hide-large-items", "Auto-hide item contents for large items.", true).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)
diff --git a/src/librustdoc/html/static/main.js b/src/librustdoc/html/static/main.js
index f112a113adc..af66a7a135a 100644
--- a/src/librustdoc/html/static/main.js
+++ b/src/librustdoc/html/static/main.js
@@ -2705,8 +2705,12 @@ function hideThemeButtonState() {
                 }
             } else if (hasClass(e, "type-contents-toggle")) {
                 let text = e.getAttribute("data-toggle-text");
-                let tog = createToggle(toggle, `Show ${text}`, null, "", true);
+                let hideItemContents = getSettingValue("auto-hide-large-items") !== "false";
+                let tog = createToggle(toggle, `Show ${text}`, null, "", !hideItemContents);
                 e.parentNode.insertBefore(tog,  e);
+                if (hideItemContents) {
+                    collapseDocs(e.previousSibling.childNodes[0], "toggle");
+                }
             }
             if (e.parentNode.id === "main") {
                 var otherMessage = "";

From e2f59f41f91ad43492e8a48b92307c9a87b2294e Mon Sep 17 00:00:00 2001
From: Manish Goregaokar <manishsmail@gmail.com>
Date: Mon, 22 Mar 2021 09:08:52 -0700
Subject: [PATCH 07/21] Update src/librustdoc/html/render/print_item.rs

Co-authored-by: Joshua Nelson <joshua@yottadb.com>
---
 src/librustdoc/html/render/print_item.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index 8db78e7718d..6272790740e 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -1363,7 +1363,7 @@ fn render_struct(
             w.write_str(" {");
             let count_fields = fields
                 .iter()
-                .filter(|f| if let clean::StructFieldItem(..) = *f.kind { true } else { false })
+                .filter(|f| matches!(clean::StructFieldItem(..) = *f.kind))
                 .count();
             let has_visible_fields = count_fields > 0;
             let toggle = should_hide_fields(count_fields);

From 846a4e9b5cc49ab42a62a15cd2813b0be34fb868 Mon Sep 17 00:00:00 2001
From: Manish Goregaokar <manishsmail@gmail.com>
Date: Mon, 22 Mar 2021 09:08:58 -0700
Subject: [PATCH 08/21] Update src/librustdoc/html/render/print_item.rs

Co-authored-by: Joshua Nelson <joshua@yottadb.com>
---
 src/librustdoc/html/render/print_item.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index 6272790740e..d5a5ecd3e88 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -1306,7 +1306,7 @@ fn render_union(
     write!(w, " {{\n{}", tab);
     let count_fields = fields
         .iter()
-        .filter(|f| if let clean::StructFieldItem(..) = *f.kind { true } else { false })
+        .filter(|f| matches!(clean::StructFieldItem(..), *f.kind))
         .count();
     let toggle = should_hide_fields(count_fields);
     if toggle {

From def144c2e752cf2040d21fbd0cf04f5779cce898 Mon Sep 17 00:00:00 2001
From: Jacob Hoffman-Andrews <github@hoffman-andrews.com>
Date: Sat, 27 Mar 2021 12:50:09 -0700
Subject: [PATCH 09/21] Improve CSS for "hide contents, not items"

Introduce a first use of the `<details>` and `<summary>` tags as
replacements for the JS-built toggles. I think this has the potential to
replace all the JS toggles and generally clean up the JS, CSS, and HTML.

Split rendering of attributes into two cases: in the case where they are
rendered as descendents of a `<pre>` tag, where they use indent spaces and
newlines for formatting, matching their surrounding markup. In the case
where they are rendered as descendants of a `<code>` tag, they are
rendered as `<div>`. This let me clean up some fragile CSS that was
adjusting the margin-left of attributes depending on context.

Remove toggles for attributes. With the ALLOWED_ATTRIBUTES filter, it's
rare for an item to have more than one attribute, so hiding attributes
behind a toggle doesn't save any screen space in the common case.

Fix a couple of invocations of `matches!` that didn't compile on my
machine.

Fix a boolean for the JS `createToggle` call that was causing
"Expand description" to show up spuriously on already-expanded
descriptions.

Add JS for auto-hide settings and hide all / show all.

Remove a z-index property and some font color tweaks made unnecessary
by the <details> toggles.

Add CSS for the <details> toggles.
---
 src/librustdoc/html/render/mod.rs           | 52 +++++++------
 src/librustdoc/html/render/print_item.rs    | 46 ++++++------
 src/librustdoc/html/static/main.js          | 58 ++++----------
 src/librustdoc/html/static/rustdoc.css      | 83 ++++++++++++---------
 src/librustdoc/html/static/storage.js       |  1 -
 src/librustdoc/html/static/themes/ayu.css   |  2 +-
 src/librustdoc/html/static/themes/dark.css  |  2 +-
 src/librustdoc/html/static/themes/light.css |  2 +-
 8 files changed, 116 insertions(+), 130 deletions(-)

diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index 00a19006bb9..d0d9034f6e6 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -43,7 +43,6 @@ use std::path::PathBuf;
 use std::str;
 use std::string::ToString;
 
-use itertools::Itertools;
 use rustc_ast_pretty::pprust;
 use rustc_attr::{Deprecation, StabilityLevel};
 use rustc_data_structures::fx::FxHashSet;
@@ -487,7 +486,6 @@ fn settings(root_path: &str, suffix: &str, themes: &[StylePath]) -> Result<Strin
         )
             .into(),
         ("auto-hide-large-items", "Auto-hide item contents for large items.", true).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(),
@@ -936,19 +934,21 @@ fn render_assoc_item(
             + name.as_str().len()
             + generics_len;
 
-        let (indent, end_newline) = if parent == ItemType::Trait {
+        let (indent, indent_str, end_newline) = if parent == ItemType::Trait {
             header_len += 4;
-            (4, false)
+            let indent_str = "    ";
+            render_attributes_in_pre(w, meth, indent_str);
+            (4, indent_str, false)
         } else {
-            (0, true)
+            render_attributes_in_code(w, meth);
+            (0, "", true)
         };
-        render_attributes(w, meth, false);
         w.reserve(header_len + "<a href=\"\" class=\"fnname\">{".len() + "</a>".len());
         write!(
             w,
             "{}{}{}{}{}{}{}fn <a href=\"{href}\" class=\"fnname\">{name}</a>\
              {generics}{decl}{notable_traits}{where_clause}",
-            if parent == ItemType::Trait { "    " } else { "" },
+            indent_str,
             vis,
             constness,
             asyncness,
@@ -1004,35 +1004,33 @@ const ALLOWED_ATTRIBUTES: &[Symbol] = &[
     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
+fn attributes(it: &clean::Item) -> Vec<String> {
+    it.attrs
         .other_attrs
         .iter()
         .filter_map(|attr| {
             if ALLOWED_ATTRIBUTES.contains(&attr.name_or_empty()) {
-                Some(pprust::attribute_to_string(&attr))
+                Some(pprust::attribute_to_string(&attr).replace("\n", "").replace("  ", " "))
             } else {
                 None
             }
         })
-        .join("\n");
+        .collect()
+}
 
-    if !attrs.is_empty() {
-        write!(
-            w,
-            "<span class=\"docblock attributes{}\">{}</span>",
-            if top { " top-attr" } else { "" },
-            &attrs
-        );
+// When an attribute is rendered inside a `<pre>` tag, it is formatted using
+// a whitespace prefix and newline.
+fn render_attributes_in_pre(w: &mut Buffer, it: &clean::Item, prefix: &str) {
+    for a in attributes(it) {
+        write!(w, "{}{}\n", prefix, a);
+    }
+}
+
+// When an attribute is rendered inside a <code> tag, it is formatted using
+// a div to produce a newline after it.
+fn render_attributes_in_code(w: &mut Buffer, it: &clean::Item) {
+    for a in attributes(it) {
+        write!(w, "<div>{}</div>", a);
     }
 }
 
diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index d5a5ecd3e88..03c4bb837f5 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -11,8 +11,8 @@ use rustc_span::symbol::{kw, sym, Symbol};
 
 use super::{
     collect_paths_for_type, document, ensure_trailing_slash, item_ty_to_strs, notable_traits_decl,
-    render_assoc_item, render_assoc_items, render_attributes, render_impl,
-    render_stability_since_raw, write_srclink, AssocItemLink, Context,
+    render_assoc_item, render_assoc_items, render_attributes_in_code, render_attributes_in_pre,
+    render_impl, render_stability_since_raw, write_srclink, AssocItemLink, Context,
 };
 use crate::clean::{self, GetDefId};
 use crate::formats::cache::Cache;
@@ -138,11 +138,15 @@ fn should_hide_fields(n_fields: usize) -> bool {
 }
 
 fn toggle_open(w: &mut Buffer, text: &str) {
-    write!(w, "<div class=\"docblock type-contents-toggle\" data-toggle-text=\"{}\">", text);
+    write!(
+        w,
+        "<details class=\"type-contents-toggle\"><summary class=\"hideme\"><span>Show {}</span></summary>",
+        text
+    );
 }
 
 fn toggle_close(w: &mut Buffer) {
-    w.write_str("</div>");
+    w.write_str("</details>");
 }
 
 fn item_module(w: &mut Buffer, cx: &Context<'_>, item: &clean::Item, items: &[clean::Item]) {
@@ -391,7 +395,7 @@ fn item_function(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, f: &clean::
     )
     .len();
     w.write_str("<pre class=\"rust fn\">");
-    render_attributes(w, it, false);
+    render_attributes_in_pre(w, it, "");
     write!(
         w,
         "{vis}{constness}{asyncness}{unsafety}{abi}fn \
@@ -420,7 +424,7 @@ fn item_trait(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Tra
     // Output the trait definition
     wrap_into_docblock(w, |w| {
         w.write_str("<pre class=\"rust trait\">");
-        render_attributes(w, it, true);
+        render_attributes_in_pre(w, it, "");
         write!(
             w,
             "{}{}{}trait {}{}{}",
@@ -729,7 +733,7 @@ fn item_trait(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Tra
 
 fn item_trait_alias(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::TraitAlias) {
     w.write_str("<pre class=\"rust trait-alias\">");
-    render_attributes(w, it, false);
+    render_attributes_in_pre(w, it, "");
     write!(
         w,
         "trait {}{}{} = {};</pre>",
@@ -750,7 +754,7 @@ fn item_trait_alias(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clea
 
 fn item_opaque_ty(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::OpaqueTy) {
     w.write_str("<pre class=\"rust opaque\">");
-    render_attributes(w, it, false);
+    render_attributes_in_pre(w, it, "");
     write!(
         w,
         "type {}{}{where_clause} = impl {bounds};</pre>",
@@ -771,7 +775,7 @@ fn item_opaque_ty(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean:
 
 fn item_typedef(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Typedef) {
     w.write_str("<pre class=\"rust typedef\">");
-    render_attributes(w, it, false);
+    render_attributes_in_pre(w, it, "");
     write!(
         w,
         "type {}{}{where_clause} = {type_};</pre>",
@@ -793,7 +797,7 @@ fn item_typedef(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::T
 fn item_union(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, s: &clean::Union) {
     wrap_into_docblock(w, |w| {
         w.write_str("<pre class=\"rust union\">");
-        render_attributes(w, it, true);
+        render_attributes_in_pre(w, it, "");
         render_union(w, it, Some(&s.generics), &s.fields, "", true, cx);
         w.write_str("</pre>")
     });
@@ -839,7 +843,7 @@ fn item_union(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, s: &clean::Uni
 fn item_enum(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, e: &clean::Enum) {
     wrap_into_docblock(w, |w| {
         w.write_str("<pre class=\"rust enum\">");
-        render_attributes(w, it, true);
+        render_attributes_in_pre(w, it, "");
         write!(
             w,
             "{}enum {}{}{}",
@@ -1019,7 +1023,7 @@ fn item_primitive(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item) {
 
 fn item_constant(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, c: &clean::Constant) {
     w.write_str("<pre class=\"rust const\">");
-    render_attributes(w, it, false);
+    render_attributes_in_code(w, it);
 
     write!(
         w,
@@ -1058,7 +1062,7 @@ fn item_constant(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, c: &clean::
 fn item_struct(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, s: &clean::Struct) {
     wrap_into_docblock(w, |w| {
         w.write_str("<pre class=\"rust struct\">");
-        render_attributes(w, it, true);
+        render_attributes_in_code(w, it);
         render_struct(w, it, Some(&s.generics), s.struct_type, &s.fields, "", true, cx);
         w.write_str("</pre>")
     });
@@ -1107,7 +1111,7 @@ fn item_struct(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, s: &clean::St
 
 fn item_static(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, s: &clean::Static) {
     w.write_str("<pre class=\"rust static\">");
-    render_attributes(w, it, false);
+    render_attributes_in_code(w, it);
     write!(
         w,
         "{vis}static {mutability}{name}: {typ}</pre>",
@@ -1121,7 +1125,7 @@ fn item_static(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, s: &clean::St
 
 fn item_foreign_type(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item) {
     w.write_str("<pre class=\"rust foreigntype\">extern {\n");
-    render_attributes(w, it, false);
+    render_attributes_in_code(w, it);
     write!(
         w,
         "    {}type {};\n}}</pre>",
@@ -1304,10 +1308,8 @@ fn render_union(
     }
 
     write!(w, " {{\n{}", tab);
-    let count_fields = fields
-        .iter()
-        .filter(|f| matches!(clean::StructFieldItem(..), *f.kind))
-        .count();
+    let count_fields =
+        fields.iter().filter(|f| matches!(*f.kind, clean::StructFieldItem(..))).count();
     let toggle = should_hide_fields(count_fields);
     if toggle {
         toggle_open(w, "fields");
@@ -1361,10 +1363,8 @@ fn render_struct(
                 write!(w, "{}", print_where_clause(g, cx.cache(), cx.tcx(), 0, true),)
             }
             w.write_str(" {");
-            let count_fields = fields
-                .iter()
-                .filter(|f| matches!(clean::StructFieldItem(..) = *f.kind))
-                .count();
+            let count_fields =
+                fields.iter().filter(|f| matches!(*f.kind, clean::StructFieldItem(..))).count();
             let has_visible_fields = count_fields > 0;
             let toggle = should_hide_fields(count_fields);
             if toggle {
diff --git a/src/librustdoc/html/static/main.js b/src/librustdoc/html/static/main.js
index af66a7a135a..1b14f67fce1 100644
--- a/src/librustdoc/html/static/main.js
+++ b/src/librustdoc/html/static/main.js
@@ -1,4 +1,3 @@
-// ignore-tidy-filelength
 // Local js definitions:
 /* global addClass, getSettingValue, hasClass */
 /* global onEach, onEachLazy, hasOwnProperty, removeClass, updateLocalStorage */
@@ -2316,6 +2315,9 @@ function hideThemeButtonState() {
         if (hasClass(innerToggle, "will-expand")) {
             updateLocalStorage("rustdoc-collapse", "false");
             removeClass(innerToggle, "will-expand");
+            onEachLazy(document.getElementsByTagName("details"), function(e) {
+                e.open = true;
+            });
             onEveryMatchingChild(innerToggle, "inner", function(e) {
                 e.innerHTML = labelForToggleButton(false);
             });
@@ -2328,6 +2330,9 @@ function hideThemeButtonState() {
         } else {
             updateLocalStorage("rustdoc-collapse", "true");
             addClass(innerToggle, "will-expand");
+            onEachLazy(document.getElementsByTagName("details"), function(e) {
+                e.open = false;
+            });
             onEveryMatchingChild(innerToggle, "inner", function(e) {
                 var parent = e.parentNode;
                 var superParent = null;
@@ -2569,6 +2574,7 @@ function hideThemeButtonState() {
         var toggle = createSimpleToggle(false);
         var hideMethodDocs = getSettingValue("auto-hide-method-docs") === "true";
         var hideImplementors = getSettingValue("auto-collapse-implementors") !== "false";
+        let hideLargeItemContents = getSettingValue("auto-hide-large-items") !== "false";
 
         var func = function(e) {
             var next = e.nextElementSibling;
@@ -2615,6 +2621,14 @@ function hideThemeButtonState() {
         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;
+                }
+            });
+        }
         if (hideMethodDocs === true) {
             impl_call = function(e, newToggle) {
                 if (e.id.match(/^impl(?:-\d+)?$/) === null) {
@@ -2703,14 +2717,6 @@ function hideThemeButtonState() {
                         }
                     });
                 }
-            } else if (hasClass(e, "type-contents-toggle")) {
-                let text = e.getAttribute("data-toggle-text");
-                let hideItemContents = getSettingValue("auto-hide-large-items") !== "false";
-                let tog = createToggle(toggle, `Show ${text}`, null, "", !hideItemContents);
-                e.parentNode.insertBefore(tog,  e);
-                if (hideItemContents) {
-                    collapseDocs(e.previousSibling.childNodes[0], "toggle");
-                }
             }
             if (e.parentNode.id === "main") {
                 var otherMessage = "";
@@ -2744,7 +2750,7 @@ function hideThemeButtonState() {
                         otherMessage,
                         fontSize,
                         extraClass,
-                        false),
+                        true),
                     e);
                 if (hasClass(e, "non-exhaustive") === true) {
                     collapseDocs(e.previousSibling.childNodes[0], "toggle");
@@ -2763,38 +2769,6 @@ function hideThemeButtonState() {
         }
     }());
 
-    function createToggleWrapper(tog) {
-        var span = document.createElement("span");
-        span.className = "toggle-label";
-        span.style.display = "none";
-        span.innerHTML = "&nbsp;Expand&nbsp;attributes";
-        tog.appendChild(span);
-
-        var wrapper = document.createElement("div");
-        wrapper.className = "toggle-wrapper toggle-attributes";
-        wrapper.appendChild(tog);
-        return wrapper;
-    }
-
-    (function() {
-        // To avoid checking on "rustdoc-item-attributes" value on every loop...
-        var itemAttributesFunc = function() {};
-        if (getSettingValue("auto-hide-attributes") !== "false") {
-            itemAttributesFunc = function(x) {
-                collapseDocs(x.previousSibling.childNodes[0], "toggle");
-            };
-        }
-        var attributesToggle = createToggleWrapper(createSimpleToggle(false));
-        onEachLazy(main.getElementsByClassName("attributes"), function(i_e) {
-            var attr_tog = attributesToggle.cloneNode(true);
-            if (hasClass(i_e, "top-attr") === true) {
-                addClass(attr_tog, "top-attr");
-            }
-            i_e.parentNode.insertBefore(attr_tog, i_e);
-            itemAttributesFunc(i_e);
-        });
-    }());
-
     (function() {
         // To avoid checking on "rustdoc-line-numbers" value on every loop...
         var lineNumbersFunc = function() {};
diff --git a/src/librustdoc/html/static/rustdoc.css b/src/librustdoc/html/static/rustdoc.css
index 309e55670b1..64972bc2389 100644
--- a/src/librustdoc/html/static/rustdoc.css
+++ b/src/librustdoc/html/static/rustdoc.css
@@ -970,10 +970,6 @@ a.test-arrow:hover{
 	position: absolute;
 	left: -23px;
 	top: 0;
-
-	/* The click event for this is defined on the document,
-	   so bubbling does not work. See https://github.com/rust-lang/rust/issues/83332 */
-	z-index: 10;
 }
 
 h3 > .collapse-toggle, h4 > .collapse-toggle {
@@ -1058,11 +1054,6 @@ h3 > .collapse-toggle, h4 > .collapse-toggle {
 	margin-top: 3px;
 }
 
-/* for hiding fields/variants/associated items */
-.enum > .toggle-wrapper + .docblock, .struct > .toggle-wrapper + .docblock, .union > .toggle-wrapper + .docblock, .trait > .toggle-wrapper + .docblock {
-	margin-left: 0px;
-}
-
 .docblock > .section-header:first-child {
 	margin-left: 15px;
 	margin-top: 0;
@@ -1076,22 +1067,6 @@ h3 > .collapse-toggle, h4 > .collapse-toggle {
 	display: block;
 }
 
-.attributes {
-	display: block;
-	margin-top: 0px !important;
-	margin-right: 0px;
-	margin-bottom: 0px !important;
-	margin-left: 30px;
-}
-.toggle-attributes.collapsed {
-	margin-bottom: 0;
-}
-.impl-items > .toggle-attributes {
-	margin-left: 20px;
-}
-.impl-items .attributes {
-	font-weight: 500;
-}
 
 :target > code {
 	opacity: 1;
@@ -1778,16 +1753,56 @@ div.name.expand::before {
 	top: 2px;
 }
 
-/* This part is to fix the "Expand attributes" part in the type declaration. */
-.type-decl > pre > .toggle-wrapper.toggle-attributes.top-attr {
-	margin-left: 0 !important;
+/* The hideme class is used on summary tags that contain a span with
+	placeholder text shown only when the toggle is closed. For instance,
+	"Expand description" or "Show methods". */
+details > summary.hideme {
+	cursor: pointer;
 }
-.type-decl > pre > .docblock.attributes.top-attr {
-	margin-left: 1.8em !important;
+
+details > summary::-webkit-details-marker {
+	display: none;
 }
-.type-decl > pre .toggle-attributes {
-	margin-left: 2.2em;
+
+details > summary.hideme > span {
+	margin-left: 9px;
+	color: #999;
 }
-.type-decl > pre > .docblock.attributes {
-	margin-left: 4em;
+
+details > summary::before {
+	content: "[+]";
+	font-weight: 300;
+	font-size: 0.8em;
+	color: #999;
+	letter-spacing: 1px;
+}
+
+details > summary.hideme::before {
+	position: relative;
+}
+
+details > summary:not(.hideme)::before {
+	float: left;
+}
+
+/* When a "hideme" summary is open and the "Expand description" or "Show
+	methods" text is hidden, we want the [-] toggle that remains to not
+	affect the layout of the items to its right. To do that, we use
+	absolute positioning. Note that we also set position: relative
+	on the parent <details> to make this work properly. */
+details[open] > summary.hideme {
+	position: absolute;
+}
+
+details[open] {
+	position: relative;
+}
+
+details[open] > summary.hideme > span {
+	display: none;
+}
+
+details[open] > summary::before {
+	content: "[−]";
+	display: inline;
 }
diff --git a/src/librustdoc/html/static/storage.js b/src/librustdoc/html/static/storage.js
index c68128516d2..2ed87fdedae 100644
--- a/src/librustdoc/html/static/storage.js
+++ b/src/librustdoc/html/static/storage.js
@@ -1,6 +1,5 @@
 // From rust:
 /* global resourcesSuffix */
-
 var darkThemes = ["dark", "ayu"];
 window.currentTheme = document.getElementById("themeStyle");
 window.mainTheme = document.getElementById("mainThemeStyle");
diff --git a/src/librustdoc/html/static/themes/ayu.css b/src/librustdoc/html/static/themes/ayu.css
index 0404fa50b99..b24f4035ca8 100644
--- a/src/librustdoc/html/static/themes/ayu.css
+++ b/src/librustdoc/html/static/themes/ayu.css
@@ -218,7 +218,7 @@ a {
 	color: #c5c5c5;
 }
 
-.docblock:not(.type-decl) a:not(.srclink):not(.test-arrow):not(.collapse-toggle),
+.docblock:not(.type-decl) a:not(.srclink):not(.test-arrow),
 .docblock-short a:not(.srclink):not(.test-arrow), .item-info a,
 #help a {
 	color: #39AFD7;
diff --git a/src/librustdoc/html/static/themes/dark.css b/src/librustdoc/html/static/themes/dark.css
index 15b485a966f..e863ed03f51 100644
--- a/src/librustdoc/html/static/themes/dark.css
+++ b/src/librustdoc/html/static/themes/dark.css
@@ -176,7 +176,7 @@ a {
 	color: #ddd;
 }
 
-.docblock:not(.type-decl) a:not(.srclink):not(.test-arrow):not(.collapse-toggle),
+.docblock:not(.type-decl) a:not(.srclink):not(.test-arrow),
 .docblock-short a:not(.srclink):not(.test-arrow), .item-info a,
 #help a {
 	color: #D2991D;
diff --git a/src/librustdoc/html/static/themes/light.css b/src/librustdoc/html/static/themes/light.css
index 4c83879e234..9335dd96d29 100644
--- a/src/librustdoc/html/static/themes/light.css
+++ b/src/librustdoc/html/static/themes/light.css
@@ -174,7 +174,7 @@ a {
 	color: #000;
 }
 
-.docblock:not(.type-decl) a:not(.srclink):not(.test-arrow):not(.collapse-toggle),
+.docblock:not(.type-decl) a:not(.srclink):not(.test-arrow),
 .docblock-short a:not(.srclink):not(.test-arrow), .item-info a,
 #help a {
 	color: #3873AD;

From 8e9882dbc4ed51a957c8abb0993f52f8b9f3ea26 Mon Sep 17 00:00:00 2001
From: Manish Goregaokar <manishsmail@gmail.com>
Date: Sat, 27 Mar 2021 18:09:31 -0700
Subject: [PATCH 10/21] Add css classes

---
 src/librustdoc/html/render/mod.rs        |  2 +-
 src/librustdoc/html/render/print_item.rs |  2 +-
 src/librustdoc/html/static/rustdoc.css   | 20 ++++++++++----------
 3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index d0d9034f6e6..ece8f4905ec 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -1030,7 +1030,7 @@ fn render_attributes_in_pre(w: &mut Buffer, it: &clean::Item, prefix: &str) {
 // a div to produce a newline after it.
 fn render_attributes_in_code(w: &mut Buffer, it: &clean::Item) {
     for a in attributes(it) {
-        write!(w, "<div>{}</div>", a);
+        write!(w, "<div class=\"code-attribute\">{}</div>", a);
     }
 }
 
diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index 03c4bb837f5..fec97d3ea55 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -140,7 +140,7 @@ fn should_hide_fields(n_fields: usize) -> bool {
 fn toggle_open(w: &mut Buffer, text: &str) {
     write!(
         w,
-        "<details class=\"type-contents-toggle\"><summary class=\"hideme\"><span>Show {}</span></summary>",
+        "<details class=\"rustdoc-toggle type-contents-toggle\"><summary class=\"hideme\"><span>Show {}</span></summary>",
         text
     );
 }
diff --git a/src/librustdoc/html/static/rustdoc.css b/src/librustdoc/html/static/rustdoc.css
index 64972bc2389..c84c045f75f 100644
--- a/src/librustdoc/html/static/rustdoc.css
+++ b/src/librustdoc/html/static/rustdoc.css
@@ -1756,20 +1756,20 @@ div.name.expand::before {
 /* The hideme class is used on summary tags that contain a span with
 	placeholder text shown only when the toggle is closed. For instance,
 	"Expand description" or "Show methods". */
-details > summary.hideme {
+details.rustdoc-toggle > summary.hideme {
 	cursor: pointer;
 }
 
-details > summary::-webkit-details-marker {
+details.rustdoc-toggle > summary::-webkit-details-marker {
 	display: none;
 }
 
-details > summary.hideme > span {
+details.rustdoc-toggle > summary.hideme > span {
 	margin-left: 9px;
 	color: #999;
 }
 
-details > summary::before {
+details.rustdoc-toggle > summary::before {
 	content: "[+]";
 	font-weight: 300;
 	font-size: 0.8em;
@@ -1777,11 +1777,11 @@ details > summary::before {
 	letter-spacing: 1px;
 }
 
-details > summary.hideme::before {
+details.rustdoc-toggle > summary.hideme::before {
 	position: relative;
 }
 
-details > summary:not(.hideme)::before {
+details.rustdoc-toggle > summary:not(.hideme)::before {
 	float: left;
 }
 
@@ -1790,19 +1790,19 @@ details > summary:not(.hideme)::before {
 	affect the layout of the items to its right. To do that, we use
 	absolute positioning. Note that we also set position: relative
 	on the parent <details> to make this work properly. */
-details[open] > summary.hideme {
+details.rustdoc-toggle[open] > summary.hideme {
 	position: absolute;
 }
 
-details[open] {
+details.rustdoc-toggle[open] {
 	position: relative;
 }
 
-details[open] > summary.hideme > span {
+details.rustdoc-toggle[open] > summary.hideme > span {
 	display: none;
 }
 
-details[open] > summary::before {
+details.rustdoc-toggle[open] > summary::before {
 	content: "[−]";
 	display: inline;
 }

From 01afa07fef09e60a979d582b52a62d94154369f5 Mon Sep 17 00:00:00 2001
From: Manish Goregaokar <manishsmail@gmail.com>
Date: Mon, 12 Apr 2021 11:41:01 -0700
Subject: [PATCH 11/21] should_hide_fields > 12

---
 src/librustdoc/html/render/print_item.rs | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index fec97d3ea55..f6cce28ea2b 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -133,8 +133,7 @@ pub(super) fn print_item(cx: &Context<'_>, item: &clean::Item, buf: &mut Buffer)
 
 /// For large structs, enums, unions, etc, determine whether to hide their fields
 fn should_hide_fields(n_fields: usize) -> bool {
-    // todo: figure out what this should be
-    n_fields > 5
+    n_fields > 12
 }
 
 fn toggle_open(w: &mut Buffer, text: &str) {

From b40bd5a9aaf8b20bdb394bf78a06490f60f13b57 Mon Sep 17 00:00:00 2001
From: Manish Goregaokar <manishsmail@gmail.com>
Date: Mon, 12 Apr 2021 12:14:41 -0700
Subject: [PATCH 12/21] Add test for item hiding

---
 src/test/rustdoc/item-hide-threshold.rs | 155 ++++++++++++++++++++++++
 1 file changed, 155 insertions(+)
 create mode 100644 src/test/rustdoc/item-hide-threshold.rs

diff --git a/src/test/rustdoc/item-hide-threshold.rs b/src/test/rustdoc/item-hide-threshold.rs
new file mode 100644
index 00000000000..616eef95662
--- /dev/null
+++ b/src/test/rustdoc/item-hide-threshold.rs
@@ -0,0 +1,155 @@
+#![allow(unused)]
+
+// @has 'item_hide_threshold/struct.PubStruct.html'
+// @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 0
+pub struct PubStruct {
+    pub a: usize,
+    pub b: usize,
+}
+
+// @has 'item_hide_threshold/struct.BigPubStruct.html'
+// @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 1
+// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show fields'
+pub struct BigPubStruct {
+    pub a: usize,
+    pub b: usize,
+    pub c: usize,
+    pub d: usize,
+    pub e: usize,
+    pub f: usize,
+    pub g: usize,
+    pub h: usize,
+    pub i: usize,
+    pub j: usize,
+    pub k: usize,
+    pub l: usize,
+    pub m: usize,
+}
+
+// @has 'item_hide_threshold/union.BigUnion.html'
+// @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 1
+// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show fields'
+pub union BigUnion {
+    pub a: usize,
+    pub b: usize,
+    pub c: usize,
+    pub d: usize,
+    pub e: usize,
+    pub f: usize,
+    pub g: usize,
+    pub h: usize,
+    pub i: usize,
+    pub j: usize,
+    pub k: usize,
+    pub l: usize,
+    pub m: usize,
+}
+
+// @has 'item_hide_threshold/union.Union.html'
+// @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 0
+pub union Union {
+    pub a: usize,
+    pub b: usize,
+    pub c: usize,
+}
+
+// @has 'item_hide_threshold/struct.PrivStruct.html'
+// @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 0
+// @has - '//div[@class="docblock type-decl"]' 'fields omitted'
+pub struct PrivStruct {
+    a: usize,
+    b: usize,
+}
+
+// @has 'item_hide_threshold/enum.Enum.html'
+// @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 0
+pub enum Enum {
+    A, B, C,
+    D {
+        a: u8,
+        b: u8
+    }
+}
+
+// @has 'item_hide_threshold/enum.LargeEnum.html'
+// @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 1
+// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show variants'
+pub enum LargeEnum {
+    A, B, C, D, E, F(u8), G, H, I, J, K, L, M
+}
+
+// @has 'item_hide_threshold/trait.Trait.html'
+// @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 0
+pub trait Trait {
+    type A;
+    #[must_use]
+    fn foo();
+    fn bar();
+}
+
+// @has 'item_hide_threshold/trait.GinormousTrait.html'
+// @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 1
+// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show associated items'
+pub trait GinormousTrait {
+    type A;
+    type B;
+    type C;
+    type D;
+    type E;
+    type F;
+    type G;
+    type H;
+    type I;
+    type J;
+    type K;
+    type L;
+    type M;
+    const N: usize = 1;
+    #[must_use]
+    fn foo();
+    fn bar();
+}
+
+// @has 'item_hide_threshold/trait.HugeTrait.html'
+// @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 1
+// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show associated constants and methods'
+pub trait HugeTrait {
+    type A;
+    const M: usize = 1;
+    const N: usize = 1;
+    const O: usize = 1;
+    const P: usize = 1;
+    const Q: usize = 1;
+    const R: usize = 1;
+    const S: usize = 1;
+    const T: usize = 1;
+    const U: usize = 1;
+    const V: usize = 1;
+    const W: usize = 1;
+    const X: usize = 1;
+    #[must_use]
+    fn foo();
+    fn bar();
+}
+
+// @has 'item_hide_threshold/trait.BigTrait.html'
+// @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 1
+// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show methods'
+pub trait BigTrait {
+    type A;
+    #[must_use]
+    fn foo();
+    fn bar();
+    fn baz();
+    fn quux();
+    fn frob();
+    fn greeble();
+    fn blap();
+    fn whoop();
+    fn pow();
+    fn bang();
+    fn oomph();
+    fn argh();
+    fn wap();
+    fn ouch();
+}

From 97cd30d337e4e460efc77faf03ba68ce192b5648 Mon Sep 17 00:00:00 2001
From: Manish Goregaokar <manishsmail@gmail.com>
Date: Mon, 12 Apr 2021 12:27:37 -0700
Subject: [PATCH 13/21] Wrap toggle_open()

---
 src/librustdoc/html/render/print_item.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index f6cce28ea2b..ff3518ad7a1 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -139,7 +139,10 @@ fn should_hide_fields(n_fields: usize) -> bool {
 fn toggle_open(w: &mut Buffer, text: &str) {
     write!(
         w,
-        "<details class=\"rustdoc-toggle type-contents-toggle\"><summary class=\"hideme\"><span>Show {}</span></summary>",
+        "<details class=\"rustdoc-toggle type-contents-toggle\">\
+            <summary class=\"hideme\">\
+                <span>Show {}</span>\
+            </summary>",
         text
     );
 }

From 05d1e723dcc00caed9f6768ea6d30962774c09f8 Mon Sep 17 00:00:00 2001
From: Manish Goregaokar <manishsmail@gmail.com>
Date: Mon, 12 Apr 2021 12:40:20 -0700
Subject: [PATCH 14/21] & -> &&

---
 src/librustdoc/html/render/print_item.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index ff3518ad7a1..ff9e4d031da 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -464,7 +464,7 @@ fn item_trait(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Tra
             // We also do this if the types + consts is large because otherwise we could
             // render a bunch of types and _then_ a bunch of consts just because both were
             // _just_ under the limit
-            if !toggle & should_hide_fields(types.len() + consts.len()) {
+            if !toggle && should_hide_fields(types.len() + consts.len()) {
                 toggle = true;
                 toggle_open(w, "associated constants and methods");
             }
@@ -475,7 +475,7 @@ fn item_trait(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Tra
                 render_assoc_item(w, t, AssocItemLink::Anchor(None), ItemType::Trait, cx);
                 w.write_str(";\n");
             }
-            if !toggle & should_hide_fields(required.len() + provided.len()) {
+            if !toggle && should_hide_fields(required.len() + provided.len()) {
                 toggle = true;
                 toggle_open(w, "methods");
             }

From 942ed31c565c16d9401f0dc7f5a1fb56125edb71 Mon Sep 17 00:00:00 2001
From: Manish Goregaokar <manishsmail@gmail.com>
Date: Mon, 12 Apr 2021 12:42:13 -0700
Subject: [PATCH 15/21] Move color to themes

---
 src/librustdoc/html/static/rustdoc.css      | 2 --
 src/librustdoc/html/static/themes/ayu.css   | 4 +++-
 src/librustdoc/html/static/themes/dark.css  | 4 +++-
 src/librustdoc/html/static/themes/light.css | 4 +++-
 4 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/librustdoc/html/static/rustdoc.css b/src/librustdoc/html/static/rustdoc.css
index c84c045f75f..0bac40b0f1b 100644
--- a/src/librustdoc/html/static/rustdoc.css
+++ b/src/librustdoc/html/static/rustdoc.css
@@ -1766,14 +1766,12 @@ details.rustdoc-toggle > summary::-webkit-details-marker {
 
 details.rustdoc-toggle > summary.hideme > span {
 	margin-left: 9px;
-	color: #999;
 }
 
 details.rustdoc-toggle > summary::before {
 	content: "[+]";
 	font-weight: 300;
 	font-size: 0.8em;
-	color: #999;
 	letter-spacing: 1px;
 }
 
diff --git a/src/librustdoc/html/static/themes/ayu.css b/src/librustdoc/html/static/themes/ayu.css
index b24f4035ca8..5f6f3d66e57 100644
--- a/src/librustdoc/html/static/themes/ayu.css
+++ b/src/librustdoc/html/static/themes/ayu.css
@@ -224,7 +224,9 @@ a {
 	color: #39AFD7;
 }
 
-.collapse-toggle {
+.collapse-toggle,
+details.rustdoc-toggle > summary.hideme > span,
+details.rustdoc-toggle > summary::before {
 	color: #999;
 }
 
diff --git a/src/librustdoc/html/static/themes/dark.css b/src/librustdoc/html/static/themes/dark.css
index e863ed03f51..2ce6cf4cc45 100644
--- a/src/librustdoc/html/static/themes/dark.css
+++ b/src/librustdoc/html/static/themes/dark.css
@@ -186,7 +186,9 @@ a.test-arrow {
 	color: #dedede;
 }
 
-.collapse-toggle {
+.collapse-toggle,
+details.rustdoc-toggle > summary.hideme > span,
+details.rustdoc-toggle > summary::before {
 	color: #999;
 }
 
diff --git a/src/librustdoc/html/static/themes/light.css b/src/librustdoc/html/static/themes/light.css
index 9335dd96d29..31b3562cfcb 100644
--- a/src/librustdoc/html/static/themes/light.css
+++ b/src/librustdoc/html/static/themes/light.css
@@ -184,7 +184,9 @@ a.test-arrow {
 	color: #f5f5f5;
 }
 
-.collapse-toggle {
+.collapse-toggle,
+details.rustdoc-toggle > summary.hideme > span,
+details.rustdoc-toggle > summary::before {
 	color: #999;
 }
 

From 5c2820b913a2d40dc3c7178176896a6c70791bb9 Mon Sep 17 00:00:00 2001
From: Manish Goregaokar <manishsmail@gmail.com>
Date: Mon, 12 Apr 2021 13:18:36 -0700
Subject: [PATCH 16/21] +ignore-tidy-filelength

---
 src/librustdoc/html/static/main.js | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/librustdoc/html/static/main.js b/src/librustdoc/html/static/main.js
index 1b14f67fce1..d71cc15a457 100644
--- a/src/librustdoc/html/static/main.js
+++ b/src/librustdoc/html/static/main.js
@@ -1,3 +1,4 @@
+// ignore-tidy-filelength
 // Local js definitions:
 /* global addClass, getSettingValue, hasClass */
 /* global onEach, onEachLazy, hasOwnProperty, removeClass, updateLocalStorage */
@@ -2574,7 +2575,7 @@ function hideThemeButtonState() {
         var toggle = createSimpleToggle(false);
         var hideMethodDocs = getSettingValue("auto-hide-method-docs") === "true";
         var hideImplementors = getSettingValue("auto-collapse-implementors") !== "false";
-        let hideLargeItemContents = getSettingValue("auto-hide-large-items") !== "false";
+        var hideLargeItemContents = getSettingValue("auto-hide-large-items") !== "false";
 
         var func = function(e) {
             var next = e.nextElementSibling;

From 0174dd6f921cc63c7e2d9aa5c01aa591f9a26745 Mon Sep 17 00:00:00 2001
From: James Addison <jay@jp-hosting.net>
Date: Mon, 12 Apr 2021 23:29:09 +0100
Subject: [PATCH 17/21] Compiler error messages: reduce assertiveness of
 message E0384

This message is emitted as guidance by the compiler when a developer attempts to reassign a value to an immutable variable.  Following the message will always currently work, but it may not always be the best course of action; following the 'consider ...' messaging pattern provides a hint to the developer that it could be wise to explore other alternatives.
---
 .../src/borrow_check/diagnostics/conflict_errors.rs    |  2 +-
 src/test/ui/assign-imm-local-twice.rs                  |  2 +-
 src/test/ui/assign-imm-local-twice.stderr              |  2 +-
 src/test/ui/async-await/issue-61452.stderr             |  2 +-
 src/test/ui/borrowck/borrowck-asm.stderr               |  4 ++--
 .../borrowck-match-binding-is-assignment.stderr        | 10 +++++-----
 src/test/ui/borrowck/immutable-arg.stderr              |  2 +-
 src/test/ui/borrowck/issue-45199.rs                    |  6 +++---
 src/test/ui/borrowck/issue-45199.stderr                |  6 +++---
 src/test/ui/command-line-diagnostics.stderr            |  2 +-
 .../ex3-both-anon-regions-one-is-struct-2.nll.stderr   |  2 +-
 .../liveness-assign-imm-local-notes.stderr             |  8 ++++----
 .../liveness-assign-imm-local-in-loop.rs               |  2 +-
 .../liveness-assign-imm-local-in-loop.stderr           |  2 +-
 .../liveness-assign-imm-local-in-op-eq.rs              |  2 +-
 .../liveness-assign-imm-local-in-op-eq.stderr          |  2 +-
 .../liveness-assign-imm-local-with-drop.rs             |  2 +-
 .../liveness-assign-imm-local-with-drop.stderr         |  2 +-
 .../liveness-assign-imm-local-with-init.rs             |  2 +-
 .../liveness-assign-imm-local-with-init.stderr         |  2 +-
 src/test/ui/llvm-asm/llvm-asm-out-assign-imm.stderr    |  2 +-
 src/test/ui/mut/mut-pattern-internal-mutability.stderr |  2 +-
 .../move-ref-patterns/borrowck-move-ref-pattern.stderr |  4 ++--
 23 files changed, 36 insertions(+), 36 deletions(-)

diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/conflict_errors.rs b/compiler/rustc_mir/src/borrow_check/diagnostics/conflict_errors.rs
index 5fdf8a8d1ee..df6f1963923 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/conflict_errors.rs
+++ b/compiler/rustc_mir/src/borrow_check/diagnostics/conflict_errors.rs
@@ -1681,7 +1681,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 if decl.can_be_made_mutable() {
                     err.span_suggestion(
                         decl.source_info.span,
-                        "make this binding mutable",
+                        "consider making this binding mutable",
                         format!("mut {}", name),
                         Applicability::MachineApplicable,
                     );
diff --git a/src/test/ui/assign-imm-local-twice.rs b/src/test/ui/assign-imm-local-twice.rs
index c1c9bf62819..b50f6ab5deb 100644
--- a/src/test/ui/assign-imm-local-twice.rs
+++ b/src/test/ui/assign-imm-local-twice.rs
@@ -1,6 +1,6 @@
 fn test() {
     let v: isize;
-    //~^ HELP make this binding mutable
+    //~^ HELP consider making this binding mutable
     //~| SUGGESTION mut v
     v = 1; //~ NOTE first assignment
     println!("v={}", v);
diff --git a/src/test/ui/assign-imm-local-twice.stderr b/src/test/ui/assign-imm-local-twice.stderr
index df0f4c4d806..bba5d8dffe4 100644
--- a/src/test/ui/assign-imm-local-twice.stderr
+++ b/src/test/ui/assign-imm-local-twice.stderr
@@ -2,7 +2,7 @@ error[E0384]: cannot assign twice to immutable variable `v`
   --> $DIR/assign-imm-local-twice.rs:7:5
    |
 LL |     let v: isize;
-   |         - help: make this binding mutable: `mut v`
+   |         - help: consider making this binding mutable: `mut v`
 ...
 LL |     v = 1;
    |     ----- first assignment to `v`
diff --git a/src/test/ui/async-await/issue-61452.stderr b/src/test/ui/async-await/issue-61452.stderr
index 5eb4b548717..f2dec87baf0 100644
--- a/src/test/ui/async-await/issue-61452.stderr
+++ b/src/test/ui/async-await/issue-61452.stderr
@@ -13,7 +13,7 @@ LL | pub async fn g(x: usize) {
    |                -
    |                |
    |                first assignment to `x`
-   |                help: make this binding mutable: `mut x`
+   |                help: consider making this binding mutable: `mut x`
 LL |     x += 1;
    |     ^^^^^^ cannot assign twice to immutable variable
 
diff --git a/src/test/ui/borrowck/borrowck-asm.stderr b/src/test/ui/borrowck/borrowck-asm.stderr
index 3dccca78415..74cf5a55b70 100644
--- a/src/test/ui/borrowck/borrowck-asm.stderr
+++ b/src/test/ui/borrowck/borrowck-asm.stderr
@@ -29,7 +29,7 @@ LL |         let x = 3;
    |             -
    |             |
    |             first assignment to `x`
-   |             help: make this binding mutable: `mut x`
+   |             help: consider making this binding mutable: `mut x`
 LL |         unsafe {
 LL |             llvm_asm!("nop" : "=r"(x));
    |                                    ^ cannot assign twice to immutable variable
@@ -41,7 +41,7 @@ LL |         let x = 3;
    |             -
    |             |
    |             first assignment to `x`
-   |             help: make this binding mutable: `mut x`
+   |             help: consider making this binding mutable: `mut x`
 LL |         unsafe {
 LL |             llvm_asm!("nop" : "+r"(x));
    |                                    ^ cannot assign twice to immutable variable
diff --git a/src/test/ui/borrowck/borrowck-match-binding-is-assignment.stderr b/src/test/ui/borrowck/borrowck-match-binding-is-assignment.stderr
index 5661ca52cba..dd22d7e2e2e 100644
--- a/src/test/ui/borrowck/borrowck-match-binding-is-assignment.stderr
+++ b/src/test/ui/borrowck/borrowck-match-binding-is-assignment.stderr
@@ -5,7 +5,7 @@ LL |         x => {
    |         -
    |         |
    |         first assignment to `x`
-   |         help: make this binding mutable: `mut x`
+   |         help: consider making this binding mutable: `mut x`
 LL |             x += 1;
    |             ^^^^^^ cannot assign twice to immutable variable
 
@@ -16,7 +16,7 @@ LL |         E::Foo(x) => {
    |                -
    |                |
    |                first assignment to `x`
-   |                help: make this binding mutable: `mut x`
+   |                help: consider making this binding mutable: `mut x`
 LL |             x += 1;
    |             ^^^^^^ cannot assign twice to immutable variable
 
@@ -27,7 +27,7 @@ LL |         S { bar: x } => {
    |                  -
    |                  |
    |                  first assignment to `x`
-   |                  help: make this binding mutable: `mut x`
+   |                  help: consider making this binding mutable: `mut x`
 LL |             x += 1;
    |             ^^^^^^ cannot assign twice to immutable variable
 
@@ -38,7 +38,7 @@ LL |         (x,) => {
    |          -
    |          |
    |          first assignment to `x`
-   |          help: make this binding mutable: `mut x`
+   |          help: consider making this binding mutable: `mut x`
 LL |             x += 1;
    |             ^^^^^^ cannot assign twice to immutable variable
 
@@ -49,7 +49,7 @@ LL |         [x,_,_] => {
    |          -
    |          |
    |          first assignment to `x`
-   |          help: make this binding mutable: `mut x`
+   |          help: consider making this binding mutable: `mut x`
 LL |             x += 1;
    |             ^^^^^^ cannot assign twice to immutable variable
 
diff --git a/src/test/ui/borrowck/immutable-arg.stderr b/src/test/ui/borrowck/immutable-arg.stderr
index 7255ca327e7..bddb0633a0b 100644
--- a/src/test/ui/borrowck/immutable-arg.stderr
+++ b/src/test/ui/borrowck/immutable-arg.stderr
@@ -2,7 +2,7 @@ error[E0384]: cannot assign to immutable argument `_x`
   --> $DIR/immutable-arg.rs:2:5
    |
 LL | fn foo(_x: u32) {
-   |        -- help: make this binding mutable: `mut _x`
+   |        -- help: consider making this binding mutable: `mut _x`
 LL |     _x = 4;
    |     ^^^^^^ cannot assign to immutable argument
 
diff --git a/src/test/ui/borrowck/issue-45199.rs b/src/test/ui/borrowck/issue-45199.rs
index cbd45cbb619..ded46e56e34 100644
--- a/src/test/ui/borrowck/issue-45199.rs
+++ b/src/test/ui/borrowck/issue-45199.rs
@@ -1,6 +1,6 @@
 fn test_drop_replace() {
     let b: Box<isize>;
-    //~^ HELP make this binding mutable
+    //~^ HELP consider making this binding mutable
     //~| SUGGESTION mut b
     b = Box::new(1);    //~ NOTE first assignment
     b = Box::new(2);    //~ ERROR cannot assign twice to immutable variable `b`
@@ -9,13 +9,13 @@ fn test_drop_replace() {
 
 fn test_call() {
     let b = Box::new(1);    //~ NOTE first assignment
-                            //~| HELP make this binding mutable
+                            //~| HELP consider making this binding mutable
                             //~| SUGGESTION mut b
     b = Box::new(2);        //~ ERROR cannot assign twice to immutable variable `b`
                             //~| NOTE cannot assign twice to immutable
 }
 
-fn test_args(b: Box<i32>) {  //~ HELP make this binding mutable
+fn test_args(b: Box<i32>) {  //~ HELP consider making this binding mutable
                                 //~| SUGGESTION mut b
     b = Box::new(2);            //~ ERROR cannot assign to immutable argument `b`
                                 //~| NOTE cannot assign to immutable argument
diff --git a/src/test/ui/borrowck/issue-45199.stderr b/src/test/ui/borrowck/issue-45199.stderr
index 83b634051bb..47aa3090827 100644
--- a/src/test/ui/borrowck/issue-45199.stderr
+++ b/src/test/ui/borrowck/issue-45199.stderr
@@ -2,7 +2,7 @@ error[E0384]: cannot assign twice to immutable variable `b`
   --> $DIR/issue-45199.rs:6:5
    |
 LL |     let b: Box<isize>;
-   |         - help: make this binding mutable: `mut b`
+   |         - help: consider making this binding mutable: `mut b`
 ...
 LL |     b = Box::new(1);
    |     - first assignment to `b`
@@ -16,7 +16,7 @@ LL |     let b = Box::new(1);
    |         -
    |         |
    |         first assignment to `b`
-   |         help: make this binding mutable: `mut b`
+   |         help: consider making this binding mutable: `mut b`
 ...
 LL |     b = Box::new(2);
    |     ^ cannot assign twice to immutable variable
@@ -25,7 +25,7 @@ error[E0384]: cannot assign to immutable argument `b`
   --> $DIR/issue-45199.rs:20:5
    |
 LL | fn test_args(b: Box<i32>) {
-   |              - help: make this binding mutable: `mut b`
+   |              - help: consider making this binding mutable: `mut b`
 LL |
 LL |     b = Box::new(2);
    |     ^ cannot assign to immutable argument
diff --git a/src/test/ui/command-line-diagnostics.stderr b/src/test/ui/command-line-diagnostics.stderr
index b3f8d8a643f..6223ad880d6 100644
--- a/src/test/ui/command-line-diagnostics.stderr
+++ b/src/test/ui/command-line-diagnostics.stderr
@@ -5,7 +5,7 @@ LL |     let x = 42;
    |         -
    |         |
    |         first assignment to `x`
-   |         help: make this binding mutable: `mut x`
+   |         help: consider making this binding mutable: `mut x`
 LL |     x = 43;
    |     ^^^^^^ cannot assign twice to immutable variable
 
diff --git a/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-one-is-struct-2.nll.stderr b/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-one-is-struct-2.nll.stderr
index 5751c319489..bbd62902d9f 100644
--- a/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-one-is-struct-2.nll.stderr
+++ b/src/test/ui/lifetimes/lifetime-errors/ex3-both-anon-regions-one-is-struct-2.nll.stderr
@@ -12,7 +12,7 @@ error[E0384]: cannot assign to immutable argument `y`
   --> $DIR/ex3-both-anon-regions-one-is-struct-2.rs:4:5
    |
 LL | fn foo(mut x: Ref, y: &u32) {
-   |                    - help: make this binding mutable: `mut y`
+   |                    - help: consider making this binding mutable: `mut y`
 LL |     y = x.b;
    |     ^^^^^^^ cannot assign to immutable argument
 
diff --git a/src/test/ui/lifetimes/lifetime-errors/liveness-assign-imm-local-notes.stderr b/src/test/ui/lifetimes/lifetime-errors/liveness-assign-imm-local-notes.stderr
index c646912d3b6..b47a47d631e 100644
--- a/src/test/ui/lifetimes/lifetime-errors/liveness-assign-imm-local-notes.stderr
+++ b/src/test/ui/lifetimes/lifetime-errors/liveness-assign-imm-local-notes.stderr
@@ -2,7 +2,7 @@ error[E0384]: cannot assign twice to immutable variable `x`
   --> $DIR/liveness-assign-imm-local-notes.rs:10:9
    |
 LL |     let x;
-   |         - help: make this binding mutable: `mut x`
+   |         - help: consider making this binding mutable: `mut x`
 ...
 LL |         x = 2;
    |         ----- first assignment to `x`
@@ -13,7 +13,7 @@ error[E0384]: cannot assign twice to immutable variable `x`
   --> $DIR/liveness-assign-imm-local-notes.rs:21:13
    |
 LL |         let x;
-   |             - help: make this binding mutable: `mut x`
+   |             - help: consider making this binding mutable: `mut x`
 ...
 LL |             x = 2;
    |             ----- first assignment to `x`
@@ -24,7 +24,7 @@ error[E0384]: cannot assign twice to immutable variable `x`
   --> $DIR/liveness-assign-imm-local-notes.rs:30:13
    |
 LL |     let x;
-   |         - help: make this binding mutable: `mut x`
+   |         - help: consider making this binding mutable: `mut x`
 ...
 LL |             x = 1;
    |             ^^^^^ cannot assign twice to immutable variable
@@ -33,7 +33,7 @@ error[E0384]: cannot assign twice to immutable variable `x`
   --> $DIR/liveness-assign-imm-local-notes.rs:32:13
    |
 LL |     let x;
-   |         - help: make this binding mutable: `mut x`
+   |         - help: consider making this binding mutable: `mut x`
 ...
 LL |             x = 1;
    |             ----- first assignment to `x`
diff --git a/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-in-loop.rs b/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-in-loop.rs
index c9e1851b9a9..08911c5bde7 100644
--- a/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-in-loop.rs
+++ b/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-in-loop.rs
@@ -1,6 +1,6 @@
 fn test() {
     let v: isize;
-    //~^ HELP make this binding mutable
+    //~^ HELP consider making this binding mutable
     //~| SUGGESTION mut v
     loop {
         v = 1; //~ ERROR cannot assign twice to immutable variable `v`
diff --git a/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-in-loop.stderr b/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-in-loop.stderr
index 69dff734ee4..66cdce7dacf 100644
--- a/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-in-loop.stderr
+++ b/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-in-loop.stderr
@@ -2,7 +2,7 @@ error[E0384]: cannot assign twice to immutable variable `v`
   --> $DIR/liveness-assign-imm-local-in-loop.rs:6:9
    |
 LL |     let v: isize;
-   |         - help: make this binding mutable: `mut v`
+   |         - help: consider making this binding mutable: `mut v`
 ...
 LL |         v = 1;
    |         ^^^^^ cannot assign twice to immutable variable
diff --git a/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-in-op-eq.rs b/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-in-op-eq.rs
index f24f7d2bcfc..1752d969086 100644
--- a/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-in-op-eq.rs
+++ b/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-in-op-eq.rs
@@ -1,6 +1,6 @@
 fn test() {
     let v: isize;
-    //~^ HELP make this binding mutable
+    //~^ HELP consider making this binding mutable
     //~| SUGGESTION mut v
     v = 2;  //~ NOTE first assignment
     v += 1; //~ ERROR cannot assign twice to immutable variable `v`
diff --git a/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-in-op-eq.stderr b/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-in-op-eq.stderr
index 182958dd492..5db9539cbf1 100644
--- a/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-in-op-eq.stderr
+++ b/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-in-op-eq.stderr
@@ -2,7 +2,7 @@ error[E0384]: cannot assign twice to immutable variable `v`
   --> $DIR/liveness-assign-imm-local-in-op-eq.rs:6:5
    |
 LL |     let v: isize;
-   |         - help: make this binding mutable: `mut v`
+   |         - help: consider making this binding mutable: `mut v`
 ...
 LL |     v = 2;
    |     ----- first assignment to `v`
diff --git a/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-with-drop.rs b/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-with-drop.rs
index 8963e32717e..c9b16e43910 100644
--- a/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-with-drop.rs
+++ b/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-with-drop.rs
@@ -1,6 +1,6 @@
 fn test() {
     let b = Box::new(1); //~ NOTE first assignment
-                         //~| HELP make this binding mutable
+                         //~| HELP consider making this binding mutable
                          //~| SUGGESTION mut b
     drop(b);
     b = Box::new(2); //~ ERROR cannot assign twice to immutable variable `b`
diff --git a/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-with-drop.stderr b/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-with-drop.stderr
index 7c4af624b27..bb7e7e27a4c 100644
--- a/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-with-drop.stderr
+++ b/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-with-drop.stderr
@@ -5,7 +5,7 @@ LL |     let b = Box::new(1);
    |         -
    |         |
    |         first assignment to `b`
-   |         help: make this binding mutable: `mut b`
+   |         help: consider making this binding mutable: `mut b`
 ...
 LL |     b = Box::new(2);
    |     ^ cannot assign twice to immutable variable
diff --git a/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-with-init.rs b/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-with-init.rs
index 4ab222af8d0..4bb2db27a16 100644
--- a/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-with-init.rs
+++ b/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-with-init.rs
@@ -1,6 +1,6 @@
 fn test() {
     let v: isize = 1; //~ NOTE first assignment
-                      //~| HELP make this binding mutable
+                      //~| HELP consider making this binding mutable
                       //~| SUGGESTION mut v
     v.clone();
     v = 2; //~ ERROR cannot assign twice to immutable variable `v`
diff --git a/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-with-init.stderr b/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-with-init.stderr
index 6f5d5574877..80458a70a01 100644
--- a/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-with-init.stderr
+++ b/src/test/ui/liveness/liveness-assign/liveness-assign-imm-local-with-init.stderr
@@ -5,7 +5,7 @@ LL |     let v: isize = 1;
    |         -
    |         |
    |         first assignment to `v`
-   |         help: make this binding mutable: `mut v`
+   |         help: consider making this binding mutable: `mut v`
 ...
 LL |     v = 2;
    |     ^^^^^ cannot assign twice to immutable variable
diff --git a/src/test/ui/llvm-asm/llvm-asm-out-assign-imm.stderr b/src/test/ui/llvm-asm/llvm-asm-out-assign-imm.stderr
index 9b0aa6be1e9..3e5893f68b6 100644
--- a/src/test/ui/llvm-asm/llvm-asm-out-assign-imm.stderr
+++ b/src/test/ui/llvm-asm/llvm-asm-out-assign-imm.stderr
@@ -2,7 +2,7 @@ error[E0384]: cannot assign twice to immutable variable `x`
   --> $DIR/llvm-asm-out-assign-imm.rs:25:39
    |
 LL |     let x: isize;
-   |         - help: make this binding mutable: `mut x`
+   |         - help: consider making this binding mutable: `mut x`
 LL |     x = 1;
    |     ----- first assignment to `x`
 ...
diff --git a/src/test/ui/mut/mut-pattern-internal-mutability.stderr b/src/test/ui/mut/mut-pattern-internal-mutability.stderr
index eaa33453a75..6583546aa5c 100644
--- a/src/test/ui/mut/mut-pattern-internal-mutability.stderr
+++ b/src/test/ui/mut/mut-pattern-internal-mutability.stderr
@@ -5,7 +5,7 @@ LL |     let &mut x = foo;
    |              -
    |              |
    |              first assignment to `x`
-   |              help: make this binding mutable: `mut x`
+   |              help: consider making this binding mutable: `mut x`
 LL |     x += 1;
    |     ^^^^^^ cannot assign twice to immutable variable
 
diff --git a/src/test/ui/pattern/move-ref-patterns/borrowck-move-ref-pattern.stderr b/src/test/ui/pattern/move-ref-patterns/borrowck-move-ref-pattern.stderr
index 285c203f382..d0726f05cc3 100644
--- a/src/test/ui/pattern/move-ref-patterns/borrowck-move-ref-pattern.stderr
+++ b/src/test/ui/pattern/move-ref-patterns/borrowck-move-ref-pattern.stderr
@@ -16,7 +16,7 @@ LL |     let [ref _x0_hold, _x1, ref xs_hold @ ..] = arr;
    |                        ---
    |                        |
    |                        first assignment to `_x1`
-   |                        help: make this binding mutable: `mut _x1`
+   |                        help: consider making this binding mutable: `mut _x1`
 LL |     _x1 = U;
    |     ^^^^^^^ cannot assign twice to immutable variable
 
@@ -74,7 +74,7 @@ LL |     let (ref _x0, _x1, ref _x2, ..) = tup;
    |                   ---
    |                   |
    |                   first assignment to `_x1`
-   |                   help: make this binding mutable: `mut _x1`
+   |                   help: consider making this binding mutable: `mut _x1`
 LL |     _x1 = U;
    |     ^^^^^^^ cannot assign twice to immutable variable
 

From 55b29443db473d49c1c64d469da5f6a50dc6beb7 Mon Sep 17 00:00:00 2001
From: Manish Goregaokar <manishsmail@gmail.com>
Date: Mon, 12 Apr 2021 23:03:17 -0700
Subject: [PATCH 18/21] Update attribute tests

---
 src/test/rustdoc/attributes.rs       | 10 +++++-----
 src/test/rustdoc/trait-attributes.rs |  6 +++---
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/test/rustdoc/attributes.rs b/src/test/rustdoc/attributes.rs
index 54c5939f908..51cd4a6cbfd 100644
--- a/src/test/rustdoc/attributes.rs
+++ b/src/test/rustdoc/attributes.rs
@@ -1,21 +1,21 @@
 #![crate_name = "foo"]
 
-// @has foo/fn.f.html '//*[@class="docblock attributes"]' '#[no_mangle]'
+// @has foo/fn.f.html '//*[@class="rust fn"]' '#[no_mangle]'
 #[no_mangle]
 pub extern "C" fn f() {}
 
-// @has foo/fn.g.html '//*[@class="docblock attributes"]' '#[export_name = "bar"]'
+// @has foo/fn.g.html '//*[@class="rust fn"]' '#[export_name = "bar"]'
 #[export_name = "bar"]
 pub extern "C" fn g() {}
 
-// @matches foo/enum.Foo.html '//*[@class="docblock attributes top-attr"]' \
-//      '(?m)\A#\[repr\(i64\)\]\n#\[must_use\]\Z'
+// @matches foo/enum.Foo.html '//*[@class="rust enum"]' \
+//      '#\[repr\(i64\)\]\n#\[must_use\]'
 #[repr(i64)]
 #[must_use]
 pub enum Foo {
     Bar,
 }
 
-// @has foo/struct.Repr.html '//*[@class="docblock attributes top-attr"]' '#[repr(C, align(8))]'
+// @has foo/struct.Repr.html '//*[@class="docblock type-decl"]' '#[repr(C, align(8))]'
 #[repr(C, align(8))]
 pub struct Repr;
diff --git a/src/test/rustdoc/trait-attributes.rs b/src/test/rustdoc/trait-attributes.rs
index 2a103509ae1..2bb24a82193 100644
--- a/src/test/rustdoc/trait-attributes.rs
+++ b/src/test/rustdoc/trait-attributes.rs
@@ -2,7 +2,7 @@
 
 
 pub trait Foo {
-    // @has foo/trait.Foo.html '//h3[@id="tymethod.foo"]//span[@class="docblock attributes"]' '#[must_use]'
+    // @has foo/trait.Foo.html '//h3[@id="tymethod.foo"]//div[@class="code-attribute"]' '#[must_use]'
     #[must_use]
     fn foo();
 }
@@ -11,11 +11,11 @@ pub trait Foo {
 pub struct Bar;
 
 impl Bar {
-    // @has foo/struct.Bar.html '//h4[@id="method.bar"]//span[@class="docblock attributes"]' '#[must_use]'
+    // @has foo/struct.Bar.html '//h4[@id="method.bar"]//div[@class="code-attribute"]' '#[must_use]'
     #[must_use]
     pub fn bar() {}
 
-    // @has foo/struct.Bar.html '//h4[@id="method.bar2"]//span[@class="docblock attributes"]' '#[must_use]'
+    // @has foo/struct.Bar.html '//h4[@id="method.bar2"]//div[@class="code-attribute"]' '#[must_use]'
     #[must_use]
     pub fn bar2() {}
 }

From bccbf9db1c799b4848c1742ddc6170e8fa94c965 Mon Sep 17 00:00:00 2001
From: Vojtech Kral <vojtech@kral.hk>
Date: Tue, 13 Apr 2021 00:10:03 +0200
Subject: [PATCH 19/21] VecDeque: binary_search_by(): return right away if hit
 found at back.first() #78021

---
 library/alloc/src/collections/vec_deque/mod.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/library/alloc/src/collections/vec_deque/mod.rs b/library/alloc/src/collections/vec_deque/mod.rs
index d3e70991ad5..e6436016711 100644
--- a/library/alloc/src/collections/vec_deque/mod.rs
+++ b/library/alloc/src/collections/vec_deque/mod.rs
@@ -2481,8 +2481,11 @@ impl<T> VecDeque<T> {
         F: FnMut(&'a T) -> Ordering,
     {
         let (front, back) = self.as_slices();
+        let cmp_back = back.first().map(|elem| f(elem));
 
-        if let Some(Ordering::Less | Ordering::Equal) = back.first().map(|elem| f(elem)) {
+        if let Some(Ordering::Equal) = cmp_back {
+            Ok(front.len())
+        } else if let Some(Ordering::Less) = cmp_back {
             back.binary_search_by(f).map(|idx| idx + front.len()).map_err(|idx| idx + front.len())
         } else {
             front.binary_search_by(f)

From e68680d30db3ba492827979b44c9f28e574e2274 Mon Sep 17 00:00:00 2001
From: Vojtech Kral <vojtech@kral.hk>
Date: Sun, 4 Apr 2021 14:50:44 +0200
Subject: [PATCH 20/21] VecDeque: Add partition_point() #78021

---
 .../alloc/src/collections/vec_deque/mod.rs    | 45 +++++++++++++++++++
 library/alloc/tests/vec_deque.rs              | 18 ++++++++
 2 files changed, 63 insertions(+)

diff --git a/library/alloc/src/collections/vec_deque/mod.rs b/library/alloc/src/collections/vec_deque/mod.rs
index e6436016711..f8516bdab0c 100644
--- a/library/alloc/src/collections/vec_deque/mod.rs
+++ b/library/alloc/src/collections/vec_deque/mod.rs
@@ -2534,6 +2534,51 @@ impl<T> VecDeque<T> {
     {
         self.binary_search_by(|k| f(k).cmp(b))
     }
+
+    /// Returns the index of the partition point according to the given predicate
+    /// (the index of the first element of the second partition).
+    ///
+    /// The deque is assumed to be partitioned according to the given predicate.
+    /// This means that all elements for which the predicate returns true are at the start of the deque
+    /// and all elements for which the predicate returns false are at the end.
+    /// For example, [7, 15, 3, 5, 4, 12, 6] is a partitioned under the predicate x % 2 != 0
+    /// (all odd numbers are at the start, all even at the end).
+    ///
+    /// If this deque is not partitioned, the returned result is unspecified and meaningless,
+    /// as this method performs a kind of binary search.
+    ///
+    /// See also [`binary_search`], [`binary_search_by`], and [`binary_search_by_key`].
+    ///
+    /// [`binary_search`]: slice::binary_search
+    /// [`binary_search_by`]: slice::binary_search_by
+    /// [`binary_search_by_key`]: slice::binary_search_by_key
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(vecdeque_binary_search)]
+    /// use std::collections::VecDeque;
+    ///
+    /// let deque: VecDeque<_> = vec![1, 2, 3, 3, 5, 6, 7].into();
+    /// let i = deque.partition_point(|&x| x < 5);
+    ///
+    /// assert_eq!(i, 4);
+    /// assert!(deque.iter().take(i).all(|&x| x < 5));
+    /// assert!(deque.iter().skip(i).all(|&x| !(x < 5)));
+    /// ```
+    #[unstable(feature = "vecdeque_binary_search", issue = "78021")]
+    pub fn partition_point<P>(&self, mut pred: P) -> usize
+    where
+        P: FnMut(&T) -> bool,
+    {
+        let (front, back) = self.as_slices();
+
+        if let Some(true) = back.first().map(|v| pred(v)) {
+            back.partition_point(pred) + front.len()
+        } else {
+            front.partition_point(pred)
+        }
+    }
 }
 
 impl<T: Clone> VecDeque<T> {
diff --git a/library/alloc/tests/vec_deque.rs b/library/alloc/tests/vec_deque.rs
index 0919b1325bc..d7140cf9759 100644
--- a/library/alloc/tests/vec_deque.rs
+++ b/library/alloc/tests/vec_deque.rs
@@ -1699,6 +1699,24 @@ fn test_binary_search_by_key() {
     assert_eq!(deque.binary_search_by_key(&4, |&(v,)| v), Err(3));
 }
 
+#[test]
+fn test_partition_point() {
+    // Contiguous (front only) search:
+    let deque: VecDeque<_> = vec![1, 2, 3, 5, 6].into();
+    assert!(deque.as_slices().1.is_empty());
+    assert_eq!(deque.partition_point(|&v| v <= 3), 3);
+
+    // Split search (both front & back non-empty):
+    let mut deque: VecDeque<_> = vec![5, 6].into();
+    deque.push_front(3);
+    deque.push_front(2);
+    deque.push_front(1);
+    deque.push_back(10);
+    assert!(!deque.as_slices().0.is_empty());
+    assert!(!deque.as_slices().1.is_empty());
+    assert_eq!(deque.partition_point(|&v| v <= 5), 4);
+}
+
 #[test]
 fn test_zero_sized_push() {
     const N: usize = 8;

From 44be1c2aa0df6ef4ff22e4aa92be3f32daf036a9 Mon Sep 17 00:00:00 2001
From: Vojtech Kral <vojtech@kral.hk>
Date: Thu, 15 Apr 2021 09:33:46 +0200
Subject: [PATCH 21/21] VecDeque: Improve doc comments in binary search fns

Co-authored-by: Mara Bos <m-ou.se@m-ou.se>
---
 .../alloc/src/collections/vec_deque/mod.rs    | 28 +++++++++++++++----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/library/alloc/src/collections/vec_deque/mod.rs b/library/alloc/src/collections/vec_deque/mod.rs
index f8516bdab0c..7d6fbf1c438 100644
--- a/library/alloc/src/collections/vec_deque/mod.rs
+++ b/library/alloc/src/collections/vec_deque/mod.rs
@@ -2403,6 +2403,12 @@ impl<T> VecDeque<T> {
     /// [`Result::Err`] is returned, containing the index where a matching
     /// element could be inserted while maintaining sorted order.
     ///
+    /// See also [`binary_search_by`], [`binary_search_by_key`], and [`partition_point`].
+    ///
+    /// [`binary_search_by`]: VecDeque::binary_search_by
+    /// [`binary_search_by_key`]: VecDeque::binary_search_by_key
+    /// [`partition_point`]: VecDeque::partition_point
+    ///
     /// # Examples
     ///
     /// Looks up a series of four elements. The first is found, with a
@@ -2457,6 +2463,12 @@ impl<T> VecDeque<T> {
     /// [`Result::Err`] is returned, containing the index where a matching
     /// element could be inserted while maintaining sorted order.
     ///
+    /// See also [`binary_search`], [`binary_search_by_key`], and [`partition_point`].
+    ///
+    /// [`binary_search`]: VecDeque::binary_search
+    /// [`binary_search_by_key`]: VecDeque::binary_search_by_key
+    /// [`partition_point`]: VecDeque::partition_point
+    ///
     /// # Examples
     ///
     /// Looks up a series of four elements. The first is found, with a
@@ -2495,8 +2507,7 @@ impl<T> VecDeque<T> {
     /// Binary searches this sorted `VecDeque` with a key extraction function.
     ///
     /// Assumes that the `VecDeque` is sorted by the key, for instance with
-    /// [`make_contiguous().sort_by_key()`](#method.make_contiguous) using the same
-    /// key extraction function.
+    /// [`make_contiguous().sort_by_key()`] using the same key extraction function.
     ///
     /// If the value is found then [`Result::Ok`] is returned, containing the
     /// index of the matching element. If there are multiple matches, then any
@@ -2504,6 +2515,13 @@ impl<T> VecDeque<T> {
     /// [`Result::Err`] is returned, containing the index where a matching
     /// element could be inserted while maintaining sorted order.
     ///
+    /// See also [`binary_search`], [`binary_search_by`], and [`partition_point`].
+    ///
+    /// [`make_contiguous().sort_by_key()`]: VecDeque::make_contiguous
+    /// [`binary_search`]: VecDeque::binary_search
+    /// [`binary_search_by`]: VecDeque::binary_search_by
+    /// [`partition_point`]: VecDeque::partition_point
+    ///
     /// # Examples
     ///
     /// Looks up a series of four elements in a slice of pairs sorted by
@@ -2549,9 +2567,9 @@ impl<T> VecDeque<T> {
     ///
     /// See also [`binary_search`], [`binary_search_by`], and [`binary_search_by_key`].
     ///
-    /// [`binary_search`]: slice::binary_search
-    /// [`binary_search_by`]: slice::binary_search_by
-    /// [`binary_search_by_key`]: slice::binary_search_by_key
+    /// [`binary_search`]: VecDeque::binary_search
+    /// [`binary_search_by`]: VecDeque::binary_search_by
+    /// [`binary_search_by_key`]: VecDeque::binary_search_by_key
     ///
     /// # Examples
     ///