rustdoc: change `.src-line-numbers > span` to `.src-line-numbers > a`

This allows people to treat them like real links, such as right-click to
copy URL, and makes the line numbers in a scraped example work at all,
when before this commit was added, they had the clickable pointer cursor
but did not actually do anything when clicked.

6 files changed, 72 insertions, 47 deletions

diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index 27dea8ec0b3..e09106077f7 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -2888,9 +2888,6 @@ fn render_call_locations(w: &mut Buffer, cx: &mut Context<'_>, item: &clean::Ite
         })()
         .unwrap_or(rustc_span::DUMMY_SP);
 
-        // The root path is the inverse of Context::current
-        let root_path = vec!["../"; cx.current.len() - 1].join("");
-
         let mut decoration_info = FxHashMap::default();
         decoration_info.insert("highlight focus", vec![byte_ranges.remove(0)]);
         decoration_info.insert("highlight", byte_ranges);
@@ -2900,9 +2897,13 @@ fn render_call_locations(w: &mut Buffer, cx: &mut Context<'_>, item: &clean::Ite
             contents_subset,
             file_span,
             cx,
-            &root_path,
+            &cx.root_path(),
             highlight::DecorationInfo(decoration_info),
-            sources::SourceContext::Embedded { offset: line_min, needs_expansion },
+            sources::SourceContext::Embedded {
+                url: &call_data.url,
+                offset: line_min,
+                needs_expansion,
+            },
         );
         write!(w, "</div></div>");
 
diff --git a/src/librustdoc/html/sources.rs b/src/librustdoc/html/sources.rs
index 8a01c01049d..99b4678c457 100644
--- a/src/librustdoc/html/sources.rs
+++ b/src/librustdoc/html/sources.rs
@@ -256,9 +256,9 @@ where
     }
 }
 
-pub(crate) enum SourceContext {
+pub(crate) enum SourceContext<'a> {
     Standalone,
-    Embedded { offset: usize, needs_expansion: bool },
+    Embedded { url: &'a str, offset: usize, needs_expansion: bool },
 }
 
 /// Wrapper struct to render the source code of a file. This will do things like
@@ -270,31 +270,32 @@ pub(crate) fn print_src(
     context: &Context<'_>,
     root_path: &str,
     decoration_info: highlight::DecorationInfo,
-    source_context: SourceContext,
+    source_context: SourceContext<'_>,
 ) {
     let lines = s.lines().count();
     let mut line_numbers = Buffer::empty_from(buf);
     let extra;
     line_numbers.write_str("<pre class=\"src-line-numbers\">");
+    let current_href = &context
+        .href_from_span(clean::Span::new(file_span), false)
+        .expect("only local crates should have sources emitted");
     match source_context {
         SourceContext::Standalone => {
             extra = None;
             for line in 1..=lines {
-                writeln!(line_numbers, "<span id=\"{0}\">{0}</span>", line)
+                writeln!(line_numbers, "<a href=\"#{line}\" id=\"{line}\">{line}</a>")
             }
         }
-        SourceContext::Embedded { offset, needs_expansion } => {
+        SourceContext::Embedded { url, offset, needs_expansion } => {
             extra =
                 if needs_expansion { Some(r#"<span class="expand">&varr;</span>"#) } else { None };
-            for line in 1..=lines {
-                writeln!(line_numbers, "<span>{0}</span>", line + offset)
+            for line_number in 1..=lines {
+                let line = line_number + offset;
+                writeln!(line_numbers, "<a href=\"{root_path}{url}#{line}\">{line}</a>")
             }
         }
     }
     line_numbers.write_str("</pre>");
-    let current_href = &context
-        .href_from_span(clean::Span::new(file_span), false)
-        .expect("only local crates should have sources emitted");
     highlight::render_source_with_highlighting(
         s,
         buf,
diff --git a/src/librustdoc/html/static/css/rustdoc.css b/src/librustdoc/html/static/css/rustdoc.css
index 894499e5c4f..df7b6e9b99a 100644
--- a/src/librustdoc/html/static/css/rustdoc.css
+++ b/src/librustdoc/html/static/css/rustdoc.css
@@ -575,8 +575,7 @@ ul.block, .block li {
 	border-color: var(--example-line-numbers-border-color);
 }
 
-.src-line-numbers span {
-	cursor: pointer;
+.src-line-numbers a {
 	color: var(--src-line-numbers-span-color);
 }
 .src-line-numbers .line-highlighted {
@@ -2060,7 +2059,7 @@ in storage.js
 	padding: 14px 0;
 }
 
-.scraped-example .code-wrapper .src-line-numbers span {
+.scraped-example .code-wrapper .src-line-numbers a {
 	padding: 0 14px;
 }
 
diff --git a/src/librustdoc/html/static/js/source-script.js b/src/librustdoc/html/static/js/source-script.js
index 0b9368dd899..5db768c1c57 100644
--- a/src/librustdoc/html/static/js/source-script.js
+++ b/src/librustdoc/html/static/js/source-script.js
@@ -157,7 +157,7 @@ function highlightSourceLines(match) {
         x.scrollIntoView();
     }
     onEachLazy(document.getElementsByClassName("src-line-numbers"), e => {
-        onEachLazy(e.getElementsByTagName("span"), i_e => {
+        onEachLazy(e.getElementsByTagName("a"), i_e => {
             removeClass(i_e, "line-highlighted");
         });
     });
@@ -188,8 +188,13 @@ const handleSourceHighlight = (function() {
 
     return ev => {
         let cur_line_id = parseInt(ev.target.id, 10);
-        // It can happen when clicking not on a line number span.
-        if (isNaN(cur_line_id)) {
+        // This event handler is attached to the entire line number column, but it should only
+        // be run if one of the anchors is clicked. It also shouldn't do anything if the anchor
+        // is clicked with a modifier key (to open a new browser tab).
+        if (isNaN(cur_line_id) ||
+            ev.ctrlKey ||
+            ev.altKey ||
+            ev.metaKey) {
             return;
         }
         ev.preventDefault();
diff --git a/src/test/rustdoc-gui/source-code-page.goml b/src/test/rustdoc-gui/source-code-page.goml
index a2dac2aa681..31d55cd7885 100644
--- a/src/test/rustdoc-gui/source-code-page.goml
+++ b/src/test/rustdoc-gui/source-code-page.goml
@@ -2,17 +2,17 @@
 goto: "file://" + |DOC_PATH| + "/src/test_docs/lib.rs.html"
 show-text: true
 // Check that we can click on the line number.
-click: ".src-line-numbers > span:nth-child(4)" // This is the span for line 4.
+click: ".src-line-numbers > a:nth-child(4)" // This is the anchor for line 4.
 // Ensure that the page URL was updated.
 assert-document-property: ({"URL": "lib.rs.html#4"}, ENDS_WITH)
 assert-attribute: ("//*[@id='4']", {"class": "line-highlighted"})
-// We now check that the good spans are highlighted
+// We now check that the good anchors are highlighted
 goto: "file://" + |DOC_PATH| + "/src/test_docs/lib.rs.html#4-6"
-assert-attribute-false: (".src-line-numbers > span:nth-child(3)", {"class": "line-highlighted"})
-assert-attribute: (".src-line-numbers > span:nth-child(4)", {"class": "line-highlighted"})
-assert-attribute: (".src-line-numbers > span:nth-child(5)", {"class": "line-highlighted"})
-assert-attribute: (".src-line-numbers > span:nth-child(6)", {"class": "line-highlighted"})
-assert-attribute-false: (".src-line-numbers > span:nth-child(7)", {"class": "line-highlighted"})
+assert-attribute-false: (".src-line-numbers > a:nth-child(3)", {"class": "line-highlighted"})
+assert-attribute: (".src-line-numbers > a:nth-child(4)", {"class": "line-highlighted"})
+assert-attribute: (".src-line-numbers > a:nth-child(5)", {"class": "line-highlighted"})
+assert-attribute: (".src-line-numbers > a:nth-child(6)", {"class": "line-highlighted"})
+assert-attribute-false: (".src-line-numbers > a:nth-child(7)", {"class": "line-highlighted"})
 
 define-function: (
     "check-colors",
@@ -21,12 +21,12 @@ define-function: (
         ("local-storage", {"rustdoc-theme": |theme|, "rustdoc-use-system-theme": "false"}),
         ("reload"),
         ("assert-css", (
-            ".src-line-numbers > span:not(.line-highlighted)",
+            ".src-line-numbers > a:not(.line-highlighted)",
             {"color": |color|, "background-color": |background_color|},
             ALL,
         )),
         ("assert-css", (
-            ".src-line-numbers > span.line-highlighted",
+            ".src-line-numbers > a.line-highlighted",
             {"color": |highlight_color|, "background-color": |highlight_background_color|},
             ALL,
         )),
@@ -57,6 +57,25 @@ call-function: ("check-colors", {
 
 // This is to ensure that the content is correctly align with the line numbers.
 compare-elements-position: ("//*[@id='1']", ".rust > code > span", ("y"))
+// Check the `href` property so that users can treat anchors as links.
+assert-property: (".src-line-numbers > a:nth-child(1)", {
+    "href": "file://" + |DOC_PATH| + "/src/test_docs/lib.rs.html#1"
+})
+assert-property: (".src-line-numbers > a:nth-child(2)", {
+    "href": "file://" + |DOC_PATH| + "/src/test_docs/lib.rs.html#2"
+})
+assert-property: (".src-line-numbers > a:nth-child(3)", {
+    "href": "file://" + |DOC_PATH| + "/src/test_docs/lib.rs.html#3"
+})
+assert-property: (".src-line-numbers > a:nth-child(4)", {
+    "href": "file://" + |DOC_PATH| + "/src/test_docs/lib.rs.html#4"
+})
+assert-property: (".src-line-numbers > a:nth-child(5)", {
+    "href": "file://" + |DOC_PATH| + "/src/test_docs/lib.rs.html#5"
+})
+assert-property: (".src-line-numbers > a:nth-child(6)", {
+    "href": "file://" + |DOC_PATH| + "/src/test_docs/lib.rs.html#6"
+})
 
 // Assert that the line numbers text is aligned to the right.
 assert-css: (".src-line-numbers", {"text-align": "right"})
@@ -66,7 +85,7 @@ assert-css: (".src-line-numbers", {"text-align": "right"})
 goto: "file://" + |DOC_PATH| + "/src/test_docs/lib.rs.html"
 // We use this assert-position to know where we will click.
 assert-position: ("//*[@id='1']", {"x": 104, "y": 112})
-// We click on the left of the "1" span but still in the "src-line-number" `<pre>`.
+// We click on the left of the "1" anchor but still in the "src-line-number" `<pre>`.
 click: (103, 103)
 assert-document-property: ({"URL": "/lib.rs.html"}, ENDS_WITH)
 
diff --git a/src/test/rustdoc/check-source-code-urls-to-def.rs b/src/test/rustdoc/check-source-code-urls-to-def.rs
index d00a3e35519..5959f9c7c59 100644
--- a/src/test/rustdoc/check-source-code-urls-to-def.rs
+++ b/src/test/rustdoc/check-source-code-urls-to-def.rs
@@ -10,14 +10,14 @@ extern crate source_code;
 
 // @has 'src/foo/check-source-code-urls-to-def.rs.html'
 
-// @has - '//a[@href="auxiliary/source-code-bar.rs.html#1-17"]' 'bar'
+// @has - '//pre[@class="rust"]//a[@href="auxiliary/source-code-bar.rs.html#1-17"]' 'bar'
 #[path = "auxiliary/source-code-bar.rs"]
 pub mod bar;
 
-// @count - '//a[@href="auxiliary/source-code-bar.rs.html#5"]' 4
+// @count - '//pre[@class="rust"]//a[@href="auxiliary/source-code-bar.rs.html#5"]' 4
 use bar::Bar;
-// @has - '//a[@href="auxiliary/source-code-bar.rs.html#13"]' 'self'
-// @has - '//a[@href="auxiliary/source-code-bar.rs.html#14"]' 'Trait'
+// @has - '//pre[@class="rust"]//a[@href="auxiliary/source-code-bar.rs.html#13"]' 'self'
+// @has - '//pre[@class="rust"]//a[@href="auxiliary/source-code-bar.rs.html#14"]' 'Trait'
 use bar::sub::{self, Trait};
 
 pub struct Foo;
@@ -28,29 +28,29 @@ impl Foo {
 
 fn babar() {}
 
-// @has - '//a/@href' '/struct.String.html'
-// @has - '//a/@href' '/primitive.u32.html'
-// @has - '//a/@href' '/primitive.str.html'
-// @count - '//a[@href="#23"]' 5
-// @has - '//a[@href="../../source_code/struct.SourceCode.html"]' 'source_code::SourceCode'
+// @has - '//pre[@class="rust"]//a/@href' '/struct.String.html'
+// @has - '//pre[@class="rust"]//a/@href' '/primitive.u32.html'
+// @has - '//pre[@class="rust"]//a/@href' '/primitive.str.html'
+// @count - '//pre[@class="rust"]//a[@href="#23"]' 5
+// @has - '//pre[@class="rust"]//a[@href="../../source_code/struct.SourceCode.html"]' 'source_code::SourceCode'
 pub fn foo(a: u32, b: &str, c: String, d: Foo, e: bar::Bar, f: source_code::SourceCode) {
     let x = 12;
     let y: Foo = Foo;
     let z: Bar = bar::Bar { field: Foo };
     babar();
-    // @has - '//a[@href="#26"]' 'hello'
+    // @has - '//pre[@class="rust"]//a[@href="#26"]' 'hello'
     y.hello();
 }
 
-// @has - '//a[@href="auxiliary/source-code-bar.rs.html#14"]' 'bar::sub::Trait'
-// @has - '//a[@href="auxiliary/source-code-bar.rs.html#14"]' 'Trait'
+// @has - '//pre[@class="rust"]//a[@href="auxiliary/source-code-bar.rs.html#14"]' 'bar::sub::Trait'
+// @has - '//pre[@class="rust"]//a[@href="auxiliary/source-code-bar.rs.html#14"]' 'Trait'
 pub fn foo2<T: bar::sub::Trait, V: Trait>(t: &T, v: &V, b: bool) {}
 
 pub trait AnotherTrait {}
 pub trait WhyNot {}
 
-// @has - '//a[@href="#49"]' 'AnotherTrait'
-// @has - '//a[@href="#50"]' 'WhyNot'
+// @has - '//pre[@class="rust"]//a[@href="#49"]' 'AnotherTrait'
+// @has - '//pre[@class="rust"]//a[@href="#50"]' 'WhyNot'
 pub fn foo3<T, V>(t: &T, v: &V)
 where
     T: AnotherTrait,
@@ -59,11 +59,11 @@ where
 
 pub trait AnotherTrait2 {}
 
-// @has - '//a[@href="#60"]' 'AnotherTrait2'
+// @has - '//pre[@class="rust"]//a[@href="#60"]' 'AnotherTrait2'
 pub fn foo4() {
     let x: Vec<AnotherTrait2> = Vec::new();
 }
 
-// @has - '//a[@href="../../foo/primitive.bool.html"]' 'bool'
+// @has - '//pre[@class="rust"]//a[@href="../../foo/primitive.bool.html"]' 'bool'
 #[doc(primitive = "bool")]
 mod whatever {}