librustdoc: Use correct heading levels.

- Avoid multiple <h1>s on a page.
- The <h#> tags should follow a semantic hierarchy.
- Cap at h6 (no h7)

17 files changed, 99 insertions, 70 deletions

diff --git a/src/librustdoc/externalfiles.rs b/src/librustdoc/externalfiles.rs
index 56d2ca57218..1fd5e2d5ef6 100644
--- a/src/librustdoc/externalfiles.rs
+++ b/src/librustdoc/externalfiles.rs
@@ -39,14 +39,14 @@ impl ExternalHtml {
         let bc = format!(
             "{}{}",
             bc,
-            Markdown(&m_bc, &[], id_map, codes, edition, playground).into_string()
+            Markdown(&m_bc, &[], id_map, codes, edition, playground, 0).into_string()
         );
         let ac = load_external_files(after_content, diag)?;
         let m_ac = load_external_files(md_after_content, diag)?;
         let ac = format!(
             "{}{}",
             ac,
-            Markdown(&m_ac, &[], id_map, codes, edition, playground).into_string()
+            Markdown(&m_ac, &[], id_map, codes, edition, playground, 0).into_string()
         );
         Some(ExternalHtml { in_header: ih, before_content: bc, after_content: ac })
     }
diff --git a/src/librustdoc/html/markdown.rs b/src/librustdoc/html/markdown.rs
index fda2512a050..56b580a0518 100644
--- a/src/librustdoc/html/markdown.rs
+++ b/src/librustdoc/html/markdown.rs
@@ -12,7 +12,7 @@
 //!
 //! let s = "My *markdown* _text_";
 //! let mut id_map = IdMap::new();
-//! let md = Markdown(s, &[], &mut id_map, ErrorCodes::Yes, Edition::Edition2015, &None);
+//! let md = Markdown(s, &[], &mut id_map, ErrorCodes::Yes, Edition::Edition2015, &None, 0);
 //! let html = md.into_string();
 //! // ... something using html
 //! ```
@@ -47,6 +47,8 @@ use pulldown_cmark::{
 #[cfg(test)]
 mod tests;
 
+const MAX_HEADER_LEVEL: u32 = 6;
+
 /// Options for rendering Markdown in the main body of documentation.
 pub(crate) fn main_body_opts() -> Options {
     Options::ENABLE_TABLES
@@ -78,6 +80,7 @@ pub struct Markdown<'a>(
     /// Default edition to use when parsing doctests (to add a `fn main`).
     pub Edition,
     pub &'a Option<Playground>,
+    pub u32,
 );
 /// A tuple struct like `Markdown` that renders the markdown with a table of contents.
 crate struct MarkdownWithToc<'a>(
@@ -489,11 +492,12 @@ struct HeadingLinks<'a, 'b, 'ids, I> {
     toc: Option<&'b mut TocBuilder>,
     buf: VecDeque<SpannedEvent<'a>>,
     id_map: &'ids mut IdMap,
+    level: u32,
 }
 
 impl<'a, 'b, 'ids, I> HeadingLinks<'a, 'b, 'ids, I> {
-    fn new(iter: I, toc: Option<&'b mut TocBuilder>, ids: &'ids mut IdMap) -> Self {
-        HeadingLinks { inner: iter, toc, buf: VecDeque::new(), id_map: ids }
+    fn new(iter: I, toc: Option<&'b mut TocBuilder>, ids: &'ids mut IdMap, level: u32) -> Self {
+        HeadingLinks { inner: iter, toc, buf: VecDeque::new(), id_map: ids, level }
     }
 }
 
@@ -530,6 +534,7 @@ impl<'a, 'b, 'ids, I: Iterator<Item = SpannedEvent<'a>>> Iterator
                 self.buf.push_front((Event::Html(format!("{} ", sec).into()), 0..0));
             }
 
+            let level = std::cmp::min(level + self.level + 1, MAX_HEADER_LEVEL);
             self.buf.push_back((Event::Html(format!("</a></h{}>", level).into()), 0..0));
 
             let start_tags = format!(
@@ -1005,7 +1010,7 @@ impl LangString {
 
 impl Markdown<'_> {
     pub fn into_string(self) -> String {
-        let Markdown(md, links, mut ids, codes, edition, playground) = self;
+        let Markdown(md, links, mut ids, codes, edition, playground, level) = self;
 
         // This is actually common enough to special-case
         if md.is_empty() {
@@ -1026,7 +1031,7 @@ impl Markdown<'_> {
 
         let mut s = String::with_capacity(md.len() * 3 / 2);
 
-        let p = HeadingLinks::new(p, None, &mut ids);
+        let p = HeadingLinks::new(p, None, &mut ids, level);
         let p = Footnotes::new(p);
         let p = LinkReplacer::new(p.map(|(ev, _)| ev), links);
         let p = TableWrapper::new(p);
@@ -1048,7 +1053,7 @@ impl MarkdownWithToc<'_> {
         let mut toc = TocBuilder::new();
 
         {
-            let p = HeadingLinks::new(p, Some(&mut toc), &mut ids);
+            let p = HeadingLinks::new(p, Some(&mut toc), &mut ids, 0);
             let p = Footnotes::new(p);
             let p = TableWrapper::new(p.map(|(ev, _)| ev));
             let p = CodeBlocks::new(p, codes, edition, playground);
@@ -1077,7 +1082,7 @@ impl MarkdownHtml<'_> {
 
         let mut s = String::with_capacity(md.len() * 3 / 2);
 
-        let p = HeadingLinks::new(p, None, &mut ids);
+        let p = HeadingLinks::new(p, None, &mut ids, 0);
         let p = Footnotes::new(p);
         let p = TableWrapper::new(p.map(|(ev, _)| ev));
         let p = CodeBlocks::new(p, codes, edition, playground);
@@ -1295,7 +1300,7 @@ crate fn markdown_links(md: &str) -> Vec<MarkdownLink> {
     // There's no need to thread an IdMap through to here because
     // the IDs generated aren't going to be emitted anywhere.
     let mut ids = IdMap::new();
-    let iter = Footnotes::new(HeadingLinks::new(p, None, &mut ids));
+    let iter = Footnotes::new(HeadingLinks::new(p, None, &mut ids, 0));
 
     for ev in iter {
         if let Event::Start(Tag::Link(kind, dest, _)) = ev.0 {
diff --git a/src/librustdoc/html/markdown/tests.rs b/src/librustdoc/html/markdown/tests.rs
index 1e4cf3381f6..c6af7e5847c 100644
--- a/src/librustdoc/html/markdown/tests.rs
+++ b/src/librustdoc/html/markdown/tests.rs
@@ -147,33 +147,33 @@ fn test_lang_string_tokenizer() {
 fn test_header() {
     fn t(input: &str, expect: &str) {
         let mut map = IdMap::new();
-        let output =
-            Markdown(input, &[], &mut map, ErrorCodes::Yes, DEFAULT_EDITION, &None).into_string();
+        let output = Markdown(input, &[], &mut map, ErrorCodes::Yes, DEFAULT_EDITION, &None, 0)
+            .into_string();
         assert_eq!(output, expect, "original: {}", input);
     }
 
     t(
         "# Foo bar",
-        "<h1 id=\"foo-bar\" class=\"section-header\"><a href=\"#foo-bar\">Foo bar</a></h1>",
+        "<h2 id=\"foo-bar\" class=\"section-header\"><a href=\"#foo-bar\">Foo bar</a></h2>",
     );
     t(
         "## Foo-bar_baz qux",
-        "<h2 id=\"foo-bar_baz-qux\" class=\"section-header\">\
-         <a href=\"#foo-bar_baz-qux\">Foo-bar_baz qux</a></h2>",
+        "<h3 id=\"foo-bar_baz-qux\" class=\"section-header\">\
+         <a href=\"#foo-bar_baz-qux\">Foo-bar_baz qux</a></h3>",
     );
     t(
         "### **Foo** *bar* baz!?!& -_qux_-%",
-        "<h3 id=\"foo-bar-baz--qux-\" class=\"section-header\">\
+        "<h4 id=\"foo-bar-baz--qux-\" class=\"section-header\">\
             <a href=\"#foo-bar-baz--qux-\"><strong>Foo</strong> \
             <em>bar</em> baz!?!&amp; -<em>qux</em>-%</a>\
-         </h3>",
+         </h4>",
     );
     t(
         "#### **Foo?** & \\*bar?!*  _`baz`_ ❤ #qux",
-        "<h4 id=\"foo--bar--baz--qux\" class=\"section-header\">\
+        "<h5 id=\"foo--bar--baz--qux\" class=\"section-header\">\
              <a href=\"#foo--bar--baz--qux\"><strong>Foo?</strong> &amp; *bar?!*  \
              <em><code>baz</code></em> ❤ #qux</a>\
-         </h4>",
+         </h5>",
     );
 }
 
@@ -182,39 +182,39 @@ fn test_header_ids_multiple_blocks() {
     let mut map = IdMap::new();
     fn t(map: &mut IdMap, input: &str, expect: &str) {
         let output =
-            Markdown(input, &[], map, ErrorCodes::Yes, DEFAULT_EDITION, &None).into_string();
+            Markdown(input, &[], map, ErrorCodes::Yes, DEFAULT_EDITION, &None, 0).into_string();
         assert_eq!(output, expect, "original: {}", input);
     }
 
     t(
         &mut map,
         "# Example",
-        "<h1 id=\"example\" class=\"section-header\"><a href=\"#example\">Example</a></h1>",
+        "<h2 id=\"example\" class=\"section-header\"><a href=\"#example\">Example</a></h2>",
     );
     t(
         &mut map,
         "# Panics",
-        "<h1 id=\"panics\" class=\"section-header\"><a href=\"#panics\">Panics</a></h1>",
+        "<h2 id=\"panics\" class=\"section-header\"><a href=\"#panics\">Panics</a></h2>",
     );
     t(
         &mut map,
         "# Example",
-        "<h1 id=\"example-1\" class=\"section-header\"><a href=\"#example-1\">Example</a></h1>",
+        "<h2 id=\"example-1\" class=\"section-header\"><a href=\"#example-1\">Example</a></h2>",
     );
     t(
         &mut map,
         "# Main",
-        "<h1 id=\"main-1\" class=\"section-header\"><a href=\"#main-1\">Main</a></h1>",
+        "<h2 id=\"main-1\" class=\"section-header\"><a href=\"#main-1\">Main</a></h2>",
     );
     t(
         &mut map,
         "# Example",
-        "<h1 id=\"example-2\" class=\"section-header\"><a href=\"#example-2\">Example</a></h1>",
+        "<h2 id=\"example-2\" class=\"section-header\"><a href=\"#example-2\">Example</a></h2>",
     );
     t(
         &mut map,
         "# Panics",
-        "<h1 id=\"panics-1\" class=\"section-header\"><a href=\"#panics-1\">Panics</a></h1>",
+        "<h2 id=\"panics-1\" class=\"section-header\"><a href=\"#panics-1\">Panics</a></h2>",
     );
 }
 
diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index 5045a99800a..69f39bb58a8 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -471,19 +471,35 @@ fn settings(root_path: &str, suffix: &str, themes: &[StylePath]) -> Result<Strin
 }
 
 fn document(w: &mut Buffer, cx: &Context<'_>, item: &clean::Item, parent: Option<&clean::Item>) {
+    document_at_level(w, cx, item, parent, 0)
+}
+
+fn document_at_level(
+    w: &mut Buffer,
+    cx: &Context<'_>,
+    item: &clean::Item,
+    parent: Option<&clean::Item>,
+    level: u32,
+) {
     if let Some(ref name) = item.name {
         info!("Documenting {}", name);
     }
     document_item_info(w, cx, item, parent);
     if parent.is_none() {
-        document_full_collapsible(w, item, cx);
+        document_full_collapsible(w, item, cx, level);
     } else {
-        document_full(w, item, cx);
+        document_full(w, item, cx, level);
     }
 }
 
 /// Render md_text as markdown.
-fn render_markdown(w: &mut Buffer, cx: &Context<'_>, md_text: &str, links: Vec<RenderedLink>) {
+fn render_markdown(
+    w: &mut Buffer,
+    cx: &Context<'_>,
+    md_text: &str,
+    links: Vec<RenderedLink>,
+    level: u32,
+) {
     let mut ids = cx.id_map.borrow_mut();
     write!(
         w,
@@ -494,7 +510,8 @@ fn render_markdown(w: &mut Buffer, cx: &Context<'_>, md_text: &str, links: Vec<R
             &mut ids,
             cx.shared.codes,
             cx.shared.edition(),
-            &cx.shared.playground
+            &cx.shared.playground,
+            level
         )
         .into_string()
     )
@@ -531,15 +548,21 @@ fn document_short(
     }
 }
 
-fn document_full_collapsible(w: &mut Buffer, item: &clean::Item, cx: &Context<'_>) {
-    document_full_inner(w, item, cx, true);
+fn document_full_collapsible(w: &mut Buffer, item: &clean::Item, cx: &Context<'_>, level: u32) {
+    document_full_inner(w, item, cx, true, level);
 }
 
-fn document_full(w: &mut Buffer, item: &clean::Item, cx: &Context<'_>) {
-    document_full_inner(w, item, cx, false);
+fn document_full(w: &mut Buffer, item: &clean::Item, cx: &Context<'_>, level: u32) {
+    document_full_inner(w, item, cx, false, level);
 }
 
-fn document_full_inner(w: &mut Buffer, item: &clean::Item, cx: &Context<'_>, is_collapsible: bool) {
+fn document_full_inner(
+    w: &mut Buffer,
+    item: &clean::Item,
+    cx: &Context<'_>,
+    is_collapsible: bool,
+    level: u32,
+) {
     if let Some(s) = cx.shared.maybe_collapsed_doc_value(item) {
         debug!("Doc block: =====\n{}\n=====", s);
         if is_collapsible {
@@ -549,10 +572,10 @@ fn document_full_inner(w: &mut Buffer, item: &clean::Item, cx: &Context<'_>, is_
                      <span>Expand description</span>\
                 </summary>",
             );
-            render_markdown(w, cx, &s, item.links(cx));
+            render_markdown(w, cx, &s, item.links(cx), level);
             w.write_str("</details>");
         } else {
-            render_markdown(w, cx, &s, item.links(cx));
+            render_markdown(w, cx, &s, item.links(cx), level);
         }
     }
 }
@@ -1321,7 +1344,7 @@ fn render_impl(
                         // because impls can't have a stability.
                         if item.doc_value().is_some() {
                             document_item_info(&mut info_buffer, cx, it, Some(parent));
-                            document_full(&mut doc_buffer, item, cx);
+                            document_full(&mut doc_buffer, item, cx, 0);
                             short_documented = false;
                         } else {
                             // In case the item isn't documented,
@@ -1339,7 +1362,7 @@ fn render_impl(
                 } else {
                     document_item_info(&mut info_buffer, cx, item, Some(parent));
                     if rendering_params.show_def_docs {
-                        document_full(&mut doc_buffer, item, cx);
+                        document_full(&mut doc_buffer, item, cx, 3);
                         short_documented = false;
                     }
                 }
@@ -1579,7 +1602,8 @@ fn render_impl(
                     &mut ids,
                     cx.shared.codes,
                     cx.shared.edition(),
-                    &cx.shared.playground
+                    &cx.shared.playground,
+                    0
                 )
                 .into_string()
             );
diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index fa0d211efe6..59a6925d8b4 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -16,10 +16,10 @@ use rustc_span::symbol::{kw, sym, Symbol};
 use rustc_target::abi::{Layout, Primitive, TagEncoding, Variants};
 
 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_in_code, render_attributes_in_pre,
-    render_impl, render_stability_since_raw, write_srclink, AssocItemLink, Context,
-    ImplRenderingParameters,
+    collect_paths_for_type, document, document_at_level, ensure_trailing_slash, item_ty_to_strs,
+    notable_traits_decl, render_assoc_item, render_assoc_items, render_attributes_in_code,
+    render_attributes_in_pre, render_impl, render_stability_since_raw, write_srclink,
+    AssocItemLink, Context, ImplRenderingParameters,
 };
 use crate::clean::{self, GetDefId};
 use crate::formats::item_type::ItemType;
@@ -626,7 +626,7 @@ fn item_trait(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Tra
         let item_type = m.type_();
         let id = cx.derive_id(format!("{}.{}", item_type, name));
         let mut content = Buffer::empty_from(w);
-        document(&mut content, cx, m, Some(t));
+        document_at_level(&mut content, cx, m, Some(t), 3);
         let toggled = !content.is_empty();
         if toggled {
             write!(w, "<details class=\"rustdoc-toggle\" open><summary>");
diff --git a/src/librustdoc/html/static/css/rustdoc.css b/src/librustdoc/html/static/css/rustdoc.css
index eb7cc9309f4..925d76956ab 100644
--- a/src/librustdoc/html/static/css/rustdoc.css
+++ b/src/librustdoc/html/static/css/rustdoc.css
@@ -126,7 +126,7 @@ h2 {
 h3 {
 	font-size: 1.3em;
 }
-h1, h2, h3, h4 {
+h1, h2, h3, h4, h5, h6 {
 	font-weight: 500;
 	margin: 20px 0 15px 0;
 	padding-bottom: 6px;
@@ -179,7 +179,7 @@ div.impl-items > div {
 	padding-left: 0;
 }
 
-h1, h2, h3, h4,
+h1, h2, h3, h4, h5, h6,
 .sidebar, a.source, .search-input, .search-results .result-name,
 .content table td:first-child > a,
 .item-left > a,
@@ -501,21 +501,20 @@ nav.sub {
 	white-space: pre-wrap;
 }
 
-.docblock h1, .docblock h2, .docblock h3, .docblock h4, .docblock h5 {
+.docblock h1, .docblock h2, .docblock h3, .docblock h4, .docblock h5, .docblock h6 {
 	border-bottom: 1px solid;
 }
 
-.top-doc .docblock h1 { font-size: 1.3em; }
-.top-doc .docblock h2 { font-size: 1.15em; }
-.top-doc .docblock h3,
+.top-doc .docblock h2 { font-size: 1.3em; }
+.top-doc .docblock h3 { font-size: 1.15em; }
 .top-doc .docblock h4,
-.top-doc .docblock h5 {
+.top-doc .docblock h5,
+.top-doc .docblock h6 {
 	font-size: 1em;
 }
 
-.docblock h1 { font-size: 1em; }
-.docblock h2 { font-size: 0.95em; }
-.docblock h3, .docblock h4, .docblock h5 { font-size: 0.9em; }
+.docblock h5 { font-size: 1em; }
+.docblock h6 { font-size: 0.95em; }
 
 .docblock {
 	margin-left: 24px;
diff --git a/src/librustdoc/html/static/css/themes/ayu.css b/src/librustdoc/html/static/css/themes/ayu.css
index c79801e8308..0fb4f95acdf 100644
--- a/src/librustdoc/html/static/css/themes/ayu.css
+++ b/src/librustdoc/html/static/css/themes/ayu.css
@@ -136,7 +136,7 @@ pre, .rustdoc.source .example-wrap {
 	border-right: 1px solid #ffb44c;
 }
 
-.docblock h1, .docblock h2, .docblock h3, .docblock h4, .docblock h5 {
+.docblock h2, .docblock h3, .docblock h4, .docblock h5, .docblock h6 {
 	border-bottom-color: #5c6773;
 }
 
diff --git a/src/librustdoc/html/static/css/themes/dark.css b/src/librustdoc/html/static/css/themes/dark.css
index d2e54070acd..4fb6f7b38bb 100644
--- a/src/librustdoc/html/static/css/themes/dark.css
+++ b/src/librustdoc/html/static/css/themes/dark.css
@@ -93,7 +93,7 @@ pre, .rustdoc.source .example-wrap {
 	background-color: #0a042f !important;
 }
 
-.docblock h1, .docblock h2, .docblock h3, .docblock h4, .docblock h5 {
+.docblock h2, .docblock h3, .docblock h4, .docblock h5, .docblock h6 {
 	border-bottom-color: #DDD;
 }
 
diff --git a/src/librustdoc/html/static/css/themes/light.css b/src/librustdoc/html/static/css/themes/light.css
index 25d810560c1..62134f025c8 100644
--- a/src/librustdoc/html/static/css/themes/light.css
+++ b/src/librustdoc/html/static/css/themes/light.css
@@ -93,7 +93,7 @@ pre, .rustdoc.source .example-wrap {
 	background-color: #f6fdb0 !important;
 }
 
-.docblock h1, .docblock h2, .docblock h3, .docblock h4, .docblock h5 {
+.docblock h2, .docblock h3, .docblock h4, .docblock h5, .docblock h6 {
 	border-bottom-color: #ddd;
 }
 
diff --git a/src/librustdoc/markdown.rs b/src/librustdoc/markdown.rs
index 2ae4897dc34..82e6231782c 100644
--- a/src/librustdoc/markdown.rs
+++ b/src/librustdoc/markdown.rs
@@ -70,7 +70,7 @@ crate fn render<P: AsRef<Path>>(
     let text = if !options.markdown_no_toc {
         MarkdownWithToc(text, &mut ids, error_codes, edition, &playground).into_string()
     } else {
-        Markdown(text, &[], &mut ids, error_codes, edition, &playground).into_string()
+        Markdown(text, &[], &mut ids, error_codes, edition, &playground, 0).into_string()
     };
 
     let err = write!(
diff --git a/src/test/rustdoc/external-cross.rs b/src/test/rustdoc/external-cross.rs
index 056ed353462..3f8e1688291 100644
--- a/src/test/rustdoc/external-cross.rs
+++ b/src/test/rustdoc/external-cross.rs
@@ -6,5 +6,5 @@
 extern crate external_cross;
 
 // @has host/struct.NeedMoreDocs.html
-// @has - '//h1' 'Cross-crate imported docs'
+// @has - '//h2' 'Cross-crate imported docs'
 pub use external_cross::NeedMoreDocs;
diff --git a/src/test/rustdoc/external-doc.rs b/src/test/rustdoc/external-doc.rs
index fc29cb252e2..bd322d67a37 100644
--- a/src/test/rustdoc/external-doc.rs
+++ b/src/test/rustdoc/external-doc.rs
@@ -1,6 +1,6 @@
 // @has external_doc/struct.IncludeStrDocs.html
-// @has - '//h1' 'External Docs'
-// @has - '//h2' 'Inline Docs'
+// @has - '//h2' 'External Docs'
+// @has - '//h3' 'Inline Docs'
 #[doc = include_str!("auxiliary/external-doc.md")]
 /// ## Inline Docs
 pub struct IncludeStrDocs;
@@ -8,7 +8,7 @@ pub struct IncludeStrDocs;
 macro_rules! dir { () => { "auxiliary" } }
 
 // @has external_doc/struct.EagerExpansion.html
-// @has - '//h1' 'External Docs'
+// @has - '//h2' 'External Docs'
 #[doc = include_str!(concat!(dir!(), "/external-doc.md"))]
 /// ## Inline Docs
 pub struct EagerExpansion;
diff --git a/src/test/rustdoc/issue-42760.rs b/src/test/rustdoc/issue-42760.rs
index b07dc3f6e96..4944f815701 100644
--- a/src/test/rustdoc/issue-42760.rs
+++ b/src/test/rustdoc/issue-42760.rs
@@ -1,5 +1,5 @@
 // @has issue_42760/struct.NonGen.html
-// @has - '//h1' 'Example'
+// @has - '//h2' 'Example'
 
 /// Item docs.
 ///
diff --git a/src/test/rustdoc/short-docblock.rs b/src/test/rustdoc/short-docblock.rs
index 74fa783174d..17c44eab091 100644
--- a/src/test/rustdoc/short-docblock.rs
+++ b/src/test/rustdoc/short-docblock.rs
@@ -2,7 +2,7 @@
 
 // @has foo/index.html '//*[@class="item-right docblock-short"]/p' 'fooo'
 // @!has foo/index.html '//*[@class="item-right docblock-short"]/p/h1' 'fooo'
-// @has foo/fn.foo.html '//h1[@id="fooo"]/a[@href="#fooo"]' 'fooo'
+// @has foo/fn.foo.html '//h2[@id="fooo"]/a[@href="#fooo"]' 'fooo'
 
 /// # fooo
 ///
@@ -11,7 +11,7 @@ pub fn foo() {}
 
 // @has foo/index.html '//*[@class="item-right docblock-short"]/p' 'mooood'
 // @!has foo/index.html '//*[@class="item-right docblock-short"]/p/h2' 'mooood'
-// @has foo/foo/index.html '//h2[@id="mooood"]/a[@href="#mooood"]' 'mooood'
+// @has foo/foo/index.html '//h3[@id="mooood"]/a[@href="#mooood"]' 'mooood'
 
 /// ## mooood
 ///
diff --git a/src/test/rustdoc/smart-punct.rs b/src/test/rustdoc/smart-punct.rs
index 5319892c99c..7ae5bd69945 100644
--- a/src/test/rustdoc/smart-punct.rs
+++ b/src/test/rustdoc/smart-punct.rs
@@ -21,7 +21,7 @@
 //! ```
 
 // @has "foo/index.html" "//p" "This is the “start” of the ‘document’! How’d you know that “it’s” the start?"
-// @has "foo/index.html" "//h1" "Header with “smart punct’”"
+// @has "foo/index.html" "//h2" "Header with “smart punct’”"
 // @has "foo/index.html" '//a[@href="https://www.rust-lang.org"]' "link with “smart punct’” – yessiree!"
 // @has "foo/index.html" '//code' "this inline code -- it shouldn't have \"smart punct\""
 // @has "foo/index.html" '//pre' "let x = \"don't smart-punct me -- please!\";"
diff --git a/src/tools/error_index_generator/main.rs b/src/tools/error_index_generator/main.rs
index 01a3fc812b2..1ba283b1781 100644
--- a/src/tools/error_index_generator/main.rs
+++ b/src/tools/error_index_generator/main.rs
@@ -125,7 +125,8 @@ impl Formatter for HTMLFormatter {
                         &mut id_map,
                         ErrorCodes::Yes,
                         DEFAULT_EDITION,
-                        &Some(playground)
+                        &Some(playground),
+                        0
                     )
                     .into_string()
                 )?
diff --git a/src/tools/tidy/src/error_codes_check.rs b/src/tools/tidy/src/error_codes_check.rs
index 53c75a46339..ae169d383b2 100644
--- a/src/tools/tidy/src/error_codes_check.rs
+++ b/src/tools/tidy/src/error_codes_check.rs
@@ -49,7 +49,7 @@ fn check_error_code_explanation(
             } else if s.contains("compile-fail") {
                 invalid_compile_fail_format = true;
             }
-        } else if s.starts_with("#### Note: this error code is no longer emitted by the compiler") {
+        } else if s.starts_with("### Note: this error code is no longer emitted by the compiler") {
             if !found_error_code {
                 error_codes.get_mut(&err_code).map(|x| x.has_test = true);
                 found_error_code = true;
@@ -64,7 +64,7 @@ fn check_if_error_code_is_test_in_explanation(f: &str, err_code: &str) -> bool {
 
     for line in f.lines() {
         let s = line.trim();
-        if s.starts_with("#### Note: this error code is no longer emitted by the compiler") {
+        if s.starts_with("### Note: this error code is no longer emitted by the compiler") {
             return true;
         }
         if s.starts_with("```") {