fix: Fix outline modules spilling inner doc injections into their parent

crates/hir_def/src/attr.rs

@@ -390,7 +390,9 @@ impl AttrsWithOwner {
                         if let InFile { file_id, value: ModuleSource::SourceFile(file) } =
                             mod_data.definition_source(db)
                         {
-                            map.merge(AttrSourceMap::new(InFile::new(file_id, &file)));
+                            map.append_module_inline_attrs(AttrSourceMap::new(InFile::new(
+                                file_id, &file,
+                            )));
                         }
                         return map;
                     }
@@ -552,6 +554,11 @@ fn inner_attributes(
 pub struct AttrSourceMap {
     source: Vec<Either<ast::Attr, ast::Comment>>,
     file_id: HirFileId,
+    /// If this map is for a module, this will be the [`HirFileId`] of the module's definition site,
+    /// while `file_id` will be the one of the module declaration site.
+    /// The usize is the index into `source` from which point on the entries reside in the def site
+    /// file.
+    mod_def_site_file_id: Option<(HirFileId, usize)>,
 }
 
 impl AttrSourceMap {
@@ -559,11 +566,19 @@ impl AttrSourceMap {
         Self {
             source: collect_attrs(owner.value).map(|(_, it)| it).collect(),
             file_id: owner.file_id,
+            mod_def_site_file_id: None,
         }
     }
 
-    fn merge(&mut self, other: Self) {
+    /// Append a second source map to this one, this is required for modules, whose outline and inline
+    /// attributes can reside in different files
+    fn append_module_inline_attrs(&mut self, other: Self) {
+        assert!(self.mod_def_site_file_id.is_none() && other.mod_def_site_file_id.is_none());
+        let len = self.source.len();
         self.source.extend(other.source);
+        if other.file_id != self.file_id {
+            self.mod_def_site_file_id = Some((other.file_id, len));
+        }
     }
 
     /// Maps the lowered `Attr` back to its original syntax node.
@@ -577,9 +592,15 @@ impl AttrSourceMap {
     }
 
     fn source_of_id(&self, id: AttrId) -> InFile<&Either<ast::Attr, ast::Comment>> {
+        let ast_idx = id.ast_index as usize;
+        let file_id = match self.mod_def_site_file_id {
+            Some((file_id, def_site_cut)) if def_site_cut <= ast_idx => file_id,
+            _ => self.file_id,
+        };
+
         self.source
-            .get(id.ast_index as usize)
-            .map(|it| InFile::new(self.file_id, it))
+            .get(ast_idx)
+            .map(|it| InFile::new(file_id, it))
             .unwrap_or_else(|| panic!("cannot find attr at index {:?}", id))
     }
 }

crates/ide/src/syntax_highlighting/test_data/highlight_doctest.html

@@ -46,6 +46,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 <span class="comment documentation">//! </span><span class="keyword injected">fn</span><span class="none injected"> </span><span class="function declaration injected">test</span><span class="parenthesis injected">(</span><span class="parenthesis injected">)</span><span class="none injected"> </span><span class="brace injected">{</span><span class="brace injected">}</span>
 <span class="comment documentation">//! ```</span>
 
+<span class="keyword">mod</span> <span class="module declaration">outline_module</span><span class="semicolon">;</span>
+
 <span class="comment documentation">/// ```</span>
 <span class="comment documentation">/// </span><span class="keyword injected">let</span><span class="none injected"> </span><span class="punctuation injected">_</span><span class="none injected"> </span><span class="operator injected">=</span><span class="none injected"> </span><span class="string_literal injected">"early doctests should not go boom"</span><span class="semicolon injected">;</span>
 <span class="comment documentation">/// ```</span>
@@ -170,4 +172,6 @@ It is beyond me why you'd use these when you got ///
     ```
     </span><span class="function documentation injected intra_doc_link">[`block_comments`]</span><span class="comment documentation"> tests these without indentation
 */</span>
-<span class="keyword">pub</span> <span class="keyword">fn</span> <span class="function declaration public">block_comments2</span><span class="parenthesis">(</span><span class="parenthesis">)</span> <span class="brace">{</span><span class="brace">}</span></code></pre>
+<span class="keyword">pub</span> <span class="keyword">fn</span> <span class="function declaration public">block_comments2</span><span class="parenthesis">(</span><span class="parenthesis">)</span> <span class="brace">{</span><span class="brace">}</span>
+
+</code></pre>

crates/ide/src/syntax_highlighting/tests.rs

@@ -641,11 +641,14 @@ fn main() {
 fn test_highlight_doc_comment() {
     check_highlighting(
         r#"
+//- /main.rs
 //! This is a module to test doc injection.
 //! ```
 //! fn test() {}
 //! ```
 
+mod outline_module;
+
 /// ```
 /// let _ = "early doctests should not go boom";
 /// ```
@@ -771,6 +774,13 @@ pub fn block_comments() {}
     [`block_comments`] tests these without indentation
 */
 pub fn block_comments2() {}
+
+//- /outline_module.rs
+//! This is an outline module whose purpose is to test that its inline attribute injection does not
+//! spill into its parent.
+//! ```
+//! fn test() {}
+//! ```
 "#
         .trim(),
         expect_file!["./test_data/highlight_doctest.html"],