fix rustdoc render_call_locations panicking because of default span DUMMY_SP pointing at non local-source file

src/librustdoc/html/render/mod.rs

@@ -2812,24 +2812,46 @@ fn render_call_locations<W: fmt::Write>(
         let needs_expansion = line_max - line_min > NUM_VISIBLE_LINES;
         let locations_encoded = serde_json::to_string(&line_ranges).unwrap();
 
-        // Look for the example file in the source map if it exists, otherwise return a dummy span
-        let file_span = (|| {
-            let source_map = tcx.sess.source_map();
-            let crate_src = tcx.sess.local_crate_source_file()?.into_local_path()?;
+        let source_map = tcx.sess.source_map();
+        let files = source_map.files();
+        let local = tcx.sess.local_crate_source_file().unwrap();
+
+        let get_file_start_pos = || {
+            let crate_src = local.clone().into_local_path()?;
             let abs_crate_src = crate_src.canonicalize().ok()?;
             let crate_root = abs_crate_src.parent()?.parent()?;
             let rel_path = path.strip_prefix(crate_root).ok()?;
-            let files = source_map.files();
-            let file = files.iter().find(|file| match &file.name {
-                FileName::Real(RealFileName::LocalPath(other_path)) => rel_path == other_path,
-                _ => false,
-            })?;
-            Some(rustc_span::Span::with_root_ctxt(
-                file.start_pos + BytePos(byte_min),
-                file.start_pos + BytePos(byte_max),
-            ))
-        })()
-        .unwrap_or(DUMMY_SP);
+            files
+                .iter()
+                .find(|file| match &file.name {
+                    FileName::Real(RealFileName::LocalPath(other_path)) => rel_path == other_path,
+                    _ => false,
+                })
+                .map(|file| file.start_pos)
+        };
+
+        // Look for the example file in the source map if it exists, otherwise
+        // return a span to the local crate's source file
+        let Some(file_span) = get_file_start_pos()
+            .or_else(|| {
+                files
+                    .iter()
+                    .find(|file| match &file.name {
+                        FileName::Real(file_name) => file_name == &local,
+                        _ => false,
+                    })
+                    .map(|file| file.start_pos)
+            })
+            .map(|start_pos| {
+                rustc_span::Span::with_root_ctxt(
+                    start_pos + BytePos(byte_min),
+                    start_pos + BytePos(byte_max),
+                )
+            })
+        else {
+            // if the fallback span can't be built, don't render the code for this example
+            return false;
+        };
 
         let mut decoration_info = FxIndexMap::default();
         decoration_info.insert("highlight focus", vec![byte_ranges.remove(0)]);

tests/rustdoc-gui/scrape-examples-ice-links.goml

@@ -0,0 +1,6 @@
+// Check that the line number column has the correct layout.
+go-to: "file://" + |DOC_PATH| + "/scrape_ice/struct.ObscurelyNamedType1.html"
+wait-for: ".scraped-example-title"
+assert-attribute: (".scraped-example-title a", {"href": "../src/bar/bar.rs.html#2"})
+click: ".scraped-example-title a"
+wait-for-property: ("h1", {"innerText": "bar/\nbar.rs"})

tests/rustdoc-gui/sidebar-source-code.goml

@@ -71,7 +71,7 @@ assert: "//*[@class='dir-entry' and @open]/*[normalize-space()='sub_mod']"
 // Only "another_folder" should be "open" in "lib2".
 assert: "//*[@class='dir-entry' and not(@open)]/*[normalize-space()='another_mod']"
 // All other trees should be collapsed.
-assert-count: ("//*[@id='src-sidebar']/details[not(normalize-space()='lib2') and not(@open)]", 12)
+assert-count: ("//*[@id='src-sidebar']/details[not(normalize-space()='lib2') and not(@open)]", 13)
 
 // We now switch to mobile mode.
 set-window-size: (600, 600)

tests/rustdoc-gui/src/scrape_examples_ice/Cargo.lock

@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "scrape_ice"
+version = "0.1.0"

tests/rustdoc-gui/src/scrape_examples_ice/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "scrape_ice"
+version = "0.1.0"
+edition = "2024"
+
+[[example]]
+name = "bar"
+path = "examples/bar.rs"
+doc-scrape-examples = true

tests/rustdoc-gui/src/scrape_examples_ice/empty.html

@@ -0,0 +1 @@
+

tests/rustdoc-gui/src/scrape_examples_ice/examples/bar.rs

@@ -0,0 +1,3 @@
+fn main() {
+    let mut bar = scrape_ice::ObscurelyNamedType1::new();
+}

tests/rustdoc-gui/src/scrape_examples_ice/src/lib.rs

@@ -0,0 +1,9 @@
+//@ run-flags:-Zrustdoc-scrape-examples
+//@ compile-flags: --html-after-content empty.html
+pub struct ObscurelyNamedType1;
+
+impl ObscurelyNamedType1 {
+    pub fn new() -> Self {
+        ObscurelyNamedType1
+    }
+}