5 files changed, 55 insertions, 4 deletions

diff --git a/crates/ide/src/file_structure.rs b/crates/ide/src/file_structure.rs
index 26793bdb4..713c76957 100644
--- a/crates/ide/src/file_structure.rs
+++ b/crates/ide/src/file_structure.rs
@@ -1,7 +1,8 @@
 use ide_db::SymbolKind;
 use syntax::{
     ast::{self, AttrsOwner, GenericParamsOwner, NameOwner},
-    match_ast, AstNode, SourceFile, SyntaxNode, TextRange, WalkEvent,
+    match_ast, AstNode, AstToken, NodeOrToken, SourceFile, SyntaxNode, SyntaxToken, TextRange,
+    WalkEvent,
 };
 
 #[derive(Debug, Clone)]
@@ -32,20 +33,32 @@ pub(crate) fn file_structure(file: &SourceFile) -> Vec<StructureNode> {
     let mut res = Vec::new();
     let mut stack = Vec::new();
 
-    for event in file.syntax().preorder() {
+    for event in file.syntax().preorder_with_tokens() {
         match event {
-            WalkEvent::Enter(node) => {
+            WalkEvent::Enter(NodeOrToken::Node(node)) => {
                 if let Some(mut symbol) = structure_node(&node) {
                     symbol.parent = stack.last().copied();
                     stack.push(res.len());
                     res.push(symbol);
                 }
             }
-            WalkEvent::Leave(node) => {
+            WalkEvent::Leave(NodeOrToken::Node(node)) => {
                 if structure_node(&node).is_some() {
                     stack.pop().unwrap();
                 }
             }
+            WalkEvent::Enter(NodeOrToken::Token(token)) => {
+                if let Some(mut symbol) = structure_token(token) {
+                    symbol.parent = stack.last().copied();
+                    stack.push(res.len());
+                    res.push(symbol);
+                }
+            }
+            WalkEvent::Leave(NodeOrToken::Token(token)) => {
+                if structure_token(token).is_some() {
+                    stack.pop().unwrap();
+                }
+            }
         }
     }
     res
@@ -159,6 +172,26 @@ fn structure_node(node: &SyntaxNode) -> Option<StructureNode> {
     }
 }
 
+fn structure_token(token: SyntaxToken) -> Option<StructureNode> {
+    if let Some(comment) = ast::Comment::cast(token) {
+        let text = comment.text().trim();
+
+        if let Some(region_name) = text.strip_prefix("// region:").map(|text| text.trim()) {
+            return Some(StructureNode {
+                parent: None,
+                label: region_name.to_string(),
+                navigation_range: comment.syntax().text_range(),
+                node_range: comment.syntax().text_range(),
+                kind: SymbolKind::Region,
+                detail: None,
+                deprecated: false,
+            });
+        }
+    }
+
+    None
+}
+
 #[cfg(test)]
 mod tests {
     use expect_test::{expect, Expect};
@@ -217,6 +250,9 @@ fn obsolete() {}
 
 #[deprecated(note = "for awhile")]
 fn very_obsolete() {}
+
+// region: Some region name
+// endregion
 "#,
             expect![[r#"
                 [
@@ -421,6 +457,15 @@ fn very_obsolete() {}
                         ),
                         deprecated: true,
                     },
+                    StructureNode {
+                        parent: None,
+                        label: "Some region name",
+                        navigation_range: 501..528,
+                        node_range: 501..528,
+                        kind: Region,
+                        detail: None,
+                        deprecated: false,
+                    },
                 ]
             "#]],
         );
diff --git a/crates/ide/src/syntax_highlighting/tags.rs b/crates/ide/src/syntax_highlighting/tags.rs
index 3c02fdb11..c7e74aed8 100644
--- a/crates/ide/src/syntax_highlighting/tags.rs
+++ b/crates/ide/src/syntax_highlighting/tags.rs
@@ -107,6 +107,7 @@ impl HlTag {
                 SymbolKind::ValueParam => "value_param",
                 SymbolKind::SelfParam => "self_keyword",
                 SymbolKind::Impl => "self_type",
+                SymbolKind::Region => "region",
             },
             HlTag::Attribute => "attribute",
             HlTag::BoolLiteral => "bool_literal",
diff --git a/crates/ide_completion/src/item.rs b/crates/ide_completion/src/item.rs
index 9a4b5217a..7b553ea7a 100644
--- a/crates/ide_completion/src/item.rs
+++ b/crates/ide_completion/src/item.rs
@@ -225,6 +225,7 @@ impl CompletionItemKind {
                 SymbolKind::Local => "lc",
                 SymbolKind::Macro => "ma",
                 SymbolKind::Module => "md",
+                SymbolKind::Region => "rn",
                 SymbolKind::SelfParam => "sp",
                 SymbolKind::Static => "sc",
                 SymbolKind::Struct => "st",
diff --git a/crates/ide_db/src/lib.rs b/crates/ide_db/src/lib.rs
index 88ee4a87d..d478841e2 100644
--- a/crates/ide_db/src/lib.rs
+++ b/crates/ide_db/src/lib.rs
@@ -148,6 +148,7 @@ pub enum SymbolKind {
     Local,
     Macro,
     Module,
+    Region,
     SelfParam,
     Static,
     Struct,
diff --git a/crates/rust-analyzer/src/to_proto.rs b/crates/rust-analyzer/src/to_proto.rs
index d415ed4d3..e88818eb0 100644
--- a/crates/rust-analyzer/src/to_proto.rs
+++ b/crates/rust-analyzer/src/to_proto.rs
@@ -60,6 +60,7 @@ pub(crate) fn symbol_kind(symbol_kind: SymbolKind) -> lsp_types::SymbolKind {
         | SymbolKind::ValueParam
         | SymbolKind::Label => lsp_types::SymbolKind::Variable,
         SymbolKind::Union => lsp_types::SymbolKind::Struct,
+        SymbolKind::Region => lsp_types::SymbolKind::Namespace,
     }
 }
 
@@ -117,6 +118,7 @@ pub(crate) fn completion_item_kind(
             SymbolKind::Local => lsp_types::CompletionItemKind::Variable,
             SymbolKind::Macro => lsp_types::CompletionItemKind::Method,
             SymbolKind::Module => lsp_types::CompletionItemKind::Module,
+            SymbolKind::Region => lsp_types::CompletionItemKind::Keyword,
             SymbolKind::SelfParam => lsp_types::CompletionItemKind::Value,
             SymbolKind::Static => lsp_types::CompletionItemKind::Value,
             SymbolKind::Struct => lsp_types::CompletionItemKind::Struct,
@@ -428,6 +430,7 @@ fn semantic_token_type_and_modifiers(
             SymbolKind::TypeAlias => semantic_tokens::TYPE_ALIAS,
             SymbolKind::Trait => lsp_types::SemanticTokenType::INTERFACE,
             SymbolKind::Macro => lsp_types::SemanticTokenType::MACRO,
+            SymbolKind::Region => lsp_types::SemanticTokenType::NAMESPACE,
         },
         HlTag::BuiltinType => semantic_tokens::BUILTIN_TYPE,
         HlTag::None => semantic_tokens::GENERIC,