10 files changed, 34 insertions, 14 deletions
diff --git a/src/doc/rustdoc/src/deprecated-features.md b/src/doc/rustdoc/src/deprecated-features.md
index 2bc6e8fc8ae..9438948af54 100644
--- a/src/doc/rustdoc/src/deprecated-features.md
+++ b/src/doc/rustdoc/src/deprecated-features.md
@@ -10,4 +10,4 @@ change in any release.
 
 In the past the most common use case for customizing passes was to omit the `strip-private` pass.
 You can do this more easily, and without risk of the pass being changed, by passing
-[`--document-private-items`](./unstable-features.md#--document-private-items).
+[`--document-private-items`](command-line-arguments.md#--document-private-items-show-items-that-are-not-public).
diff --git a/src/doc/rustdoc/src/unstable-features.md b/src/doc/rustdoc/src/unstable-features.md
index 30b3d6defb4..32b35007490 100644
--- a/src/doc/rustdoc/src/unstable-features.md
+++ b/src/doc/rustdoc/src/unstable-features.md
@@ -466,7 +466,7 @@ Note that the third item is the crate root, which in this case is undocumented.
 and is also accepted on stable toolchains.
 
 It can also be used with `--show-coverage`. Take a look at its
-[documentation](#--show-coverage-get-statistics-about-code-documentation-coverage) for more
+[documentation](#--show-coverage-calculate-the-percentage-of-items-with-documentation) for more
 information.
 
 ### `--enable-per-target-ignores`: allow `ignore-foo` style filters for doctests
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index c9ef4748a48..07237438a0d 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -1993,6 +1993,7 @@ fn clean_maybe_renamed_item<'tcx>(
             ItemKind::Trait(_, _, generics, bounds, item_ids) => {
                 let items =
                     item_ids.iter().map(|ti| cx.tcx.hir().trait_item(ti.id).clean(cx)).collect();
+
                 TraitItem(Trait {
                     def_id,
                     items,
diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index 81cc12c9d55..dcd2eaac7ea 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -1,9 +1,5 @@
 use clean::AttributesExt;
 
-use std::cmp::Ordering;
-use std::fmt;
-use std::rc::Rc;
-
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_hir as hir;
 use rustc_hir::def::CtorKind;
@@ -15,6 +11,9 @@ use rustc_middle::ty::{Adt, TyCtxt};
 use rustc_span::hygiene::MacroKind;
 use rustc_span::symbol::{kw, sym, Symbol};
 use rustc_target::abi::{Layout, Primitive, TagEncoding, Variants};
+use std::cmp::Ordering;
+use std::fmt;
+use std::rc::Rc;
 
 use super::{
     collect_paths_for_type, document, ensure_trailing_slash, item_ty_to_section,
@@ -37,6 +36,7 @@ use crate::html::markdown::{HeadingOffset, MarkdownSummaryLine};
 use crate::html::url_parts_builder::UrlPartsBuilder;
 
 use askama::Template;
+use itertools::Itertools;
 
 const ITEM_TABLE_OPEN: &str = "<div class=\"item-table\">";
 const ITEM_TABLE_CLOSE: &str = "</div>";
@@ -539,6 +539,8 @@ fn item_trait(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean:
     let count_types = required_types.len() + provided_types.len();
     let count_consts = required_consts.len() + provided_consts.len();
     let count_methods = required_methods.len() + provided_methods.len();
+    let must_implement_one_of_functions =
+        cx.tcx().trait_def(t.def_id).must_implement_one_of.clone();
 
     // Output the trait definition
     wrap_into_docblock(w, |w| {
@@ -784,13 +786,22 @@ fn item_trait(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean:
     }
 
     // Output the documentation for each function individually
-    if !required_methods.is_empty() {
+    if !required_methods.is_empty() || must_implement_one_of_functions.is_some() {
         write_small_section_header(
             w,
             "required-methods",
             "Required Methods",
             "<div class=\"methods\">",
         );
+
+        if let Some(list) = must_implement_one_of_functions.as_deref() {
+            write!(
+                w,
+                "<div class=\"stab must_implement\">At least one of the `{}` methods is required.</div>",
+                list.iter().join("`, `")
+            );
+        }
+
         for m in required_methods {
             trait_item(w, cx, m, it);
         }
diff --git a/src/librustdoc/html/static/css/themes/ayu.css b/src/librustdoc/html/static/css/themes/ayu.css
index 7ff8063904a..c42cac59bd6 100644
--- a/src/librustdoc/html/static/css/themes/ayu.css
+++ b/src/librustdoc/html/static/css/themes/ayu.css
@@ -205,11 +205,13 @@ details.rustdoc-toggle > summary::before {
 
 /* Created this empty rule to satisfy the theme checks. */
 .stab.empty-impl {}
+.stab.must_implement {}
 
 .stab.unstable,
 .stab.deprecated,
 .stab.portability,
-.stab.empty-impl {
+.stab.empty-impl,
+.stab.must_implement {
 	color: #c5c5c5;
 	background: #314559 !important;
 	border-style: none !important;
diff --git a/src/librustdoc/html/static/css/themes/dark.css b/src/librustdoc/html/static/css/themes/dark.css
index 8e753f57682..62d9eaa02e6 100644
--- a/src/librustdoc/html/static/css/themes/dark.css
+++ b/src/librustdoc/html/static/css/themes/dark.css
@@ -180,6 +180,7 @@ details.rustdoc-toggle > summary::before {
 .stab.empty-impl { background: #FFF5D6; border-color: #FFC600; color: #2f2f2f; }
 .stab.unstable { background: #FFF5D6; border-color: #FFC600; color: #2f2f2f; }
 .stab.deprecated { background: #ffc4c4; border-color: #db7b7b; color: #2f2f2f; }
+.stab.must_implement { background: #F3DFFF; border-color: #b07bdb; color: #2f2f2f; }
 .stab.portability { background: #F3DFFF; border-color: #b07bdb; color: #2f2f2f; }
 .stab.portability > code { background: none; }
 
diff --git a/src/librustdoc/html/static/css/themes/light.css b/src/librustdoc/html/static/css/themes/light.css
index 40d965c39c3..b751acff152 100644
--- a/src/librustdoc/html/static/css/themes/light.css
+++ b/src/librustdoc/html/static/css/themes/light.css
@@ -163,6 +163,7 @@ details.rustdoc-toggle > summary::before {
 .stab.empty-impl { background: #FFF5D6; border-color: #FFC600; }
 .stab.unstable { background: #FFF5D6; border-color: #FFC600; }
 .stab.deprecated { background: #ffc4c4; border-color: #db7b7b; }
+.stab.must_implement { background: #F3DFFF; border-color: #b07bdb; }
 .stab.portability { background: #F3DFFF; border-color: #b07bdb; }
 .stab.portability > code { background: none; }
 
diff --git a/src/test/rustdoc/must_implement_one_of.rs b/src/test/rustdoc/must_implement_one_of.rs
new file mode 100644
index 00000000000..1f1dd5d5796
--- /dev/null
+++ b/src/test/rustdoc/must_implement_one_of.rs
@@ -0,0 +1,10 @@
+#![crate_name = "c"]
+#![feature(rustc_attrs)]
+
+#[rustc_must_implement_one_of(a, b)]
+// @matches c/trait.Trait.html '//*[@class="stab must_implement"]' \
+//      'At least one of the `a`, `b` methods is required.$'
+pub trait Trait {
+    fn a() {}
+    fn b() {}
+}
diff --git a/src/test/ui/issues/issue-30371.rs b/src/test/ui/issues/issue-30371.rs
index 58521b95cf6..a1ae9a36bc1 100644
--- a/src/test/ui/issues/issue-30371.rs
+++ b/src/test/ui/issues/issue-30371.rs
@@ -1,6 +1,5 @@
 // run-pass
 #![allow(unreachable_code)]
-#![allow(unused_mut)] // rust-lang/rust#54586
 #![deny(unused_variables)]
 
 fn main() {
diff --git a/src/tools/linkchecker/main.rs b/src/tools/linkchecker/main.rs
index c9b1649200d..a7c78d80ccd 100644
--- a/src/tools/linkchecker/main.rs
+++ b/src/tools/linkchecker/main.rs
@@ -348,11 +348,6 @@ impl Checker {
                     return;
                 }
 
-                // These appear to be broken in mdbook right now?
-                if fragment.starts_with('-') {
-                    return;
-                }
-
                 parse_ids(&mut target_ids.borrow_mut(), &pretty_path, target_source, report);
 
                 if target_ids.borrow().contains(*fragment) {