5 files changed, 27 insertions, 4 deletions
diff --git a/src/librustdoc/html/static/css/rustdoc.css b/src/librustdoc/html/static/css/rustdoc.css
index b1de8c1529e..da4da50106a 100644
--- a/src/librustdoc/html/static/css/rustdoc.css
+++ b/src/librustdoc/html/static/css/rustdoc.css
@@ -270,7 +270,7 @@ ul ul, ol ul, ul ol, ol ol {
 	margin-bottom: .625em;
 }
 
-p {
+p, .docblock > .warning {
 	/* Paragraph spacing at least 1.5 times line spacing per Web Content Accessibility Guidelines.
 	   Line-height is 1.5rem, so line spacing is .5rem; .75em is 1.5 times that.
 	   https://www.w3.org/WAI/WCAG21/Understanding/visual-presentation.html */
@@ -278,7 +278,7 @@ p {
 }
 /* For the last child of a div, the margin will be taken care of
 	by the margin-top of the next item. */
-p:last-child {
+p:last-child, .docblock > .warning:last-child {
 	margin: 0;
 }
 
@@ -1096,7 +1096,7 @@ pre.rust .doccomment {
 }
 
 .example-wrap.ignore .tooltip {
-	color:  var(--codeblock-ignore-color);
+	color: var(--codeblock-ignore-color);
 }
 
 .example-wrap.compile_fail:hover .tooltip,
@@ -1124,6 +1124,26 @@ pre.rust .doccomment {
 	font-size: 1.25rem;
 }
 
+/* This class only exists for users who want to draw attention to a particular element in their
+documentation. */
+.content .docblock .warning {
+	border-left: 2px solid var(--warning-border-color);
+	padding: 14px;
+	position: relative;
+	/* The "!important" part is required because the rule is otherwise overruled in this CSS
+	selector: ".docblock > :not(.more-examples-toggle):not(.example-wrap)" */
+	overflow-x: visible !important;
+}
+.content .docblock .warning::before {
+	color: var(--warning-border-color);
+	content: "ⓘ";
+	position: absolute;
+	left: -25px;
+	top: 5px;
+	font-weight: bold;
+	font-size: 1.25rem;
+}
+
 a.test-arrow {
 	visibility: hidden;
 	position: absolute;
diff --git a/src/librustdoc/html/static/css/themes/ayu.css b/src/librustdoc/html/static/css/themes/ayu.css
index d8dae51eb1b..c81a80eeca0 100644
--- a/src/librustdoc/html/static/css/themes/ayu.css
+++ b/src/librustdoc/html/static/css/themes/ayu.css
@@ -31,6 +31,7 @@ Original by Dempfi (https://github.com/dempfi/ayu)
 	--codeblock-error-color: rgba(255, 0, 0, .5);
 	--codeblock-ignore-hover-color: rgb(255, 142, 0);
 	--codeblock-ignore-color: rgba(255, 142, 0, .6);
+	--warning-border-color: rgb(255, 142, 0);
 	--type-link-color: #ffa0a5;
 	--trait-link-color: #39afd7;
 	--assoc-item-link-color: #39afd7;
diff --git a/src/librustdoc/html/static/css/themes/dark.css b/src/librustdoc/html/static/css/themes/dark.css
index 2b302988734..0f8b1dc24a6 100644
--- a/src/librustdoc/html/static/css/themes/dark.css
+++ b/src/librustdoc/html/static/css/themes/dark.css
@@ -26,6 +26,7 @@
 	--codeblock-error-color: rgba(255, 0, 0, .5);
 	--codeblock-ignore-hover-color: rgb(255, 142, 0);
 	--codeblock-ignore-color: rgba(255, 142, 0, .6);
+	--warning-border-color: rgb(255, 142, 0);
 	--type-link-color: #2dbfb8;
 	--trait-link-color: #b78cf2;
 	--assoc-item-link-color: #d2991d;
diff --git a/src/librustdoc/html/static/css/themes/light.css b/src/librustdoc/html/static/css/themes/light.css
index 56fd8cbef12..39ea44a1165 100644
--- a/src/librustdoc/html/static/css/themes/light.css
+++ b/src/librustdoc/html/static/css/themes/light.css
@@ -26,6 +26,7 @@
 	--codeblock-error-color: rgba(255, 0, 0, .5);
 	--codeblock-ignore-hover-color: rgb(255, 142, 0);
 	--codeblock-ignore-color: rgba(255, 142, 0, .6);
+	--warning-border-color: rgb(255, 142, 0);
 	--type-link-color: #ad378a;
 	--trait-link-color: #6e4fc9;
 	--assoc-item-link-color: #3873ad;
diff --git a/src/librustdoc/html/static/js/main.js b/src/librustdoc/html/static/js/main.js
index 254b0d8bf5a..cb653d6b8df 100644
--- a/src/librustdoc/html/static/js/main.js
+++ b/src/librustdoc/html/static/js/main.js
@@ -499,7 +499,7 @@ function preLoadCss(cssUrl) {
             block("static", "static", "Statics");
             block("trait", "traits", "Traits");
             block("fn", "functions", "Functions");
-            block("type", "types", "Type Definitions");
+            block("type", "types", "Type Aliases");
             block("foreigntype", "foreign-types", "Foreign Types");
             block("keyword", "keywords", "Keywords");
             block("traitalias", "trait-aliases", "Trait Aliases");