Merge #2291

2291: Show expanded macro in vscode r=matklad a=edwin0cheng

*Edited*

![new_screen_shot](https://user-images.githubusercontent.com/11014119/69169852-00550c00-0b34-11ea-9c40-8ecebdca0621.gif)



Co-authored-by: Edwin Cheng <[email protected]>

3 files changed, 41 insertions, 0 deletions

diff --git a/crates/ra_lsp_server/src/main_loop.rs b/crates/ra_lsp_server/src/main_loop.rs
index 379dab438..f828efdee 100644
--- a/crates/ra_lsp_server/src/main_loop.rs
+++ b/crates/ra_lsp_server/src/main_loop.rs
@@ -436,6 +436,7 @@ fn on_request(
         })?
         .on::<req::AnalyzerStatus>(handlers::handle_analyzer_status)?
         .on::<req::SyntaxTree>(handlers::handle_syntax_tree)?
+        .on::<req::ExpandMacro>(handlers::handle_expand_macro)?
         .on::<req::OnTypeFormatting>(handlers::handle_on_type_formatting)?
         .on::<req::DocumentSymbolRequest>(handlers::handle_document_symbol)?
         .on::<req::WorkspaceSymbol>(handlers::handle_workspace_symbol)?
diff --git a/crates/ra_lsp_server/src/main_loop/handlers.rs b/crates/ra_lsp_server/src/main_loop/handlers.rs
index 20f9aee13..0461bf385 100644
--- a/crates/ra_lsp_server/src/main_loop/handlers.rs
+++ b/crates/ra_lsp_server/src/main_loop/handlers.rs
@@ -47,6 +47,24 @@ pub fn handle_syntax_tree(world: WorldSnapshot, params: req::SyntaxTreeParams) -
     Ok(res)
 }
 
+pub fn handle_expand_macro(
+    world: WorldSnapshot,
+    params: req::ExpandMacroParams,
+) -> Result<Option<req::ExpandedMacro>> {
+    let _p = profile("handle_expand_macro");
+    let file_id = params.text_document.try_conv_with(&world)?;
+    let line_index = world.analysis().file_line_index(file_id)?;
+    let offset = params.position.map(|p| p.conv_with(&line_index));
+
+    match offset {
+        None => Ok(None),
+        Some(offset) => {
+            let res = world.analysis().expand_macro(FilePosition { file_id, offset })?;
+            Ok(res.map(|it| req::ExpandedMacro { name: it.name, expansion: it.expansion }))
+        }
+    }
+}
+
 pub fn handle_selection_range(
     world: WorldSnapshot,
     params: req::SelectionRangeParams,
diff --git a/crates/ra_lsp_server/src/req.rs b/crates/ra_lsp_server/src/req.rs
index d25fc5726..39361b7e8 100644
--- a/crates/ra_lsp_server/src/req.rs
+++ b/crates/ra_lsp_server/src/req.rs
@@ -45,6 +45,28 @@ pub struct SyntaxTreeParams {
     pub range: Option<Range>,
 }
 
+#[derive(Serialize, Debug)]
+#[serde(rename_all = "camelCase")]
+pub struct ExpandedMacro {
+    pub name: String,
+    pub expansion: String,
+}
+
+pub enum ExpandMacro {}
+
+impl Request for ExpandMacro {
+    type Params = ExpandMacroParams;
+    type Result = Option<ExpandedMacro>;
+    const METHOD: &'static str = "rust-analyzer/expandMacro";
+}
+
+#[derive(Deserialize, Debug)]
+#[serde(rename_all = "camelCase")]
+pub struct ExpandMacroParams {
+    pub text_document: TextDocumentIdentifier,
+    pub position: Option<Position>,
+}
+
 pub enum SelectionRangeRequest {}
 
 impl Request for SelectionRangeRequest {