rustdoc: don't give depreciation notes special handling in future edition

src/librustdoc/html/markdown.rs

@@ -111,7 +111,11 @@ pub(crate) struct MarkdownWithToc<'a> {
 }
 /// A tuple struct like `Markdown` that renders the markdown escaping HTML tags
 /// and includes no paragraph tags.
-pub(crate) struct MarkdownItemInfo<'a>(pub(crate) &'a str, pub(crate) &'a mut IdMap);
+pub(crate) struct MarkdownItemInfo<'a>(
+    pub(crate) &'a str,
+    pub(crate) &'a mut IdMap,
+    pub(crate) Edition,
+);
 /// A tuple struct like `Markdown` that renders only the first paragraph.
 pub(crate) struct MarkdownSummaryLine<'a>(pub &'a str, pub &'a [RenderedLink]);
 
@@ -1461,7 +1465,8 @@ impl MarkdownWithToc<'_> {
 
 impl MarkdownItemInfo<'_> {
     pub(crate) fn write_into(self, mut f: impl fmt::Write) -> fmt::Result {
-        let MarkdownItemInfo(md, ids) = self;
+        let MarkdownItemInfo(md, ids, edition) = self;
+        let legacy_wrap = edition != Edition::EditionFuture;
 
         // This is actually common enough to special-case
         if md.is_empty() {
@@ -1479,10 +1484,23 @@ impl MarkdownItemInfo<'_> {
             let p = HeadingLinks::new(p, None, ids, HeadingOffset::H1);
             let p = footnotes::Footnotes::new(p, existing_footnotes);
             let p = TableWrapper::new(p.map(|(ev, _)| ev));
+            // in legacy wrap mode, strip <p> elements to avoid them inserting newlines
             let p = p.filter(|event| {
-                !matches!(event, Event::Start(Tag::Paragraph) | Event::End(TagEnd::Paragraph))
+                !legacy_wrap
+                    || !matches!(
+                        event,
+                        Event::Start(Tag::Paragraph) | Event::End(TagEnd::Paragraph)
+                    )
             });
-            html::write_html_fmt(&mut f, p)
+            if legacy_wrap {
+                f.write_str("<span class=\"legacy-wrap\">")?;
+            }
+            html::write_html_fmt(&mut f, p)?;
+            if legacy_wrap {
+                f.write_str("</span>")?;
+            }
+
+            Ok(())
         })
     }
 }

src/librustdoc/html/markdown/tests.rs

@@ -467,12 +467,31 @@ fn test_plain_text_summary() {
 }
 
 #[test]
-fn test_markdown_html_escape() {
+fn test_markdown_html_escape_legacy() {
     fn t(input: &str, expect: &str) {
         let mut idmap = IdMap::new();
         let mut output = String::new();
-        MarkdownItemInfo(input, &mut idmap).write_into(&mut output).unwrap();
-        assert_eq!(output, expect, "original: {}", input);
+        MarkdownItemInfo(input, &mut idmap, Edition::Edition2015).write_into(&mut output).unwrap();
+        assert_eq!(
+            output,
+            format!("<span class=\"legacy-wrap\">{}</span>", expect),
+            "original: {}",
+            input
+        );
+    }
+
+    t("`Struct<'a, T>`", "<code>Struct&lt;'a, T&gt;</code>");
+    t("Struct<'a, T>", "Struct&lt;’a, T&gt;");
+    t("Struct<br>", "Struct&lt;br&gt;");
+}
+
+#[test]
+fn test_markdown_html_escape_new() {
+    fn t(input: &str, expect: &str) {
+        let mut idmap = IdMap::new();
+        let mut output = String::new();
+        MarkdownItemInfo(input, &mut idmap, Edition::Edition2015).write_into(&mut output).unwrap();
+        assert_eq!(output, format!("<p>{}</p>", expect), "original: {}", input);
     }
 
     t("`Struct<'a, T>`", "<code>Struct&lt;'a, T&gt;</code>");

src/librustdoc/html/render/mod.rs

@@ -855,6 +855,7 @@ fn short_item_info(
     parent: Option<&clean::Item>,
 ) -> Vec<ShortItemInfo> {
     let mut extra_info = vec![];
+    let edition = item.span(cx.tcx()).expect("unable to get edition of span").inner().edition();
 
     if let Some(depr @ Deprecation { note, since, suggestion: _ }) = item.deprecation(cx.tcx()) {
         // We display deprecation messages for #[deprecated], but only display
@@ -877,7 +878,7 @@ fn short_item_info(
         if let Some(note) = note {
             let note = note.as_str();
             let mut id_map = cx.id_map.borrow_mut();
-            let html = MarkdownItemInfo(note, &mut id_map);
+            let html = MarkdownItemInfo(note, &mut id_map, edition);
             message.push_str(": ");
             html.write_into(&mut message).unwrap();
         }

src/librustdoc/html/static/css/rustdoc.css

@@ -1577,7 +1577,6 @@ so that we can apply CSS-filters to change the arrow color in themes */
 	color: var(--main-color);
 	background-color: var(--stab-background-color);
 	width: fit-content;
-	white-space: pre-wrap;
 	border-radius: 3px;
 	display: inline;
 	vertical-align: baseline;
@@ -1588,6 +1587,10 @@ so that we can apply CSS-filters to change the arrow color in themes */
 	color: var(--stab-code-color);
 }
 
+.stab span.legacy-wrap {
+	white-space: pre-wrap;
+}
+
 .stab .emoji, .item-info .stab::before {
 	font-size: 1.25rem;
 }

tests/rustdoc/deprecated.rs

@@ -1,3 +1,6 @@
+//@ compile-flags: -Zunstable-options
+//@ edition: future
+
 //@ has deprecated/index.html '//dt/span[@class="stab deprecated"]' 'Deprecated'
 //@ has - '//dd' 'Deprecated docs'
 
@@ -30,3 +33,8 @@ pub struct W;
 //      'Deprecated: shorthand reason: code$'
 #[deprecated = "shorthand reason: `code`"]
 pub struct X;
+
+//@ matches deprecated/struct.Y.html '//*[@class="stab deprecated"]//p[1]' 'multiple'
+//@ matches deprecated/struct.Y.html '//*[@class="stab deprecated"]//p[2]' 'paragraphs'
+#[deprecated = "multiple\n\nparagraphs"]
+pub struct Y;