4 files changed, 29 insertions, 1 deletions

diff --git a/crates/server/src/caps.rs b/crates/server/src/caps.rs
index 98499bb05..7456aea8a 100644
--- a/crates/server/src/caps.rs
+++ b/crates/server/src/caps.rs
@@ -5,6 +5,7 @@ use languageserver_types::{
     TextDocumentSyncKind,
     ExecuteCommandOptions,
     CompletionOptions,
+    DocumentOnTypeFormattingOptions,
 };
 
 pub fn server_capabilities() -> ServerCapabilities {
@@ -35,7 +36,10 @@ pub fn server_capabilities() -> ServerCapabilities {
         code_lens_provider: None,
         document_formatting_provider: None,
         document_range_formatting_provider: None,
-        document_on_type_formatting_provider: None,
+        document_on_type_formatting_provider: Some(DocumentOnTypeFormattingOptions {
+            first_trigger_character: "=".to_string(),
+            more_trigger_character: None,
+        }),
         rename_provider: None,
         color_provider: None,
         execute_command_provider: Some(ExecuteCommandOptions {
diff --git a/crates/server/src/main_loop/handlers.rs b/crates/server/src/main_loop/handlers.rs
index ec5421f06..ca5cd5ab1 100644
--- a/crates/server/src/main_loop/handlers.rs
+++ b/crates/server/src/main_loop/handlers.rs
@@ -314,6 +314,25 @@ pub fn handle_completion(
     Ok(Some(req::CompletionResponse::Array(items)))
 }
 
+pub fn handle_on_type_formatting(
+    world: ServerWorld,
+    params: req::DocumentOnTypeFormattingParams,
+) -> Result<Option<Vec<TextEdit>>> {
+    if params.ch != "=" {
+        return Ok(None);
+    }
+
+    let file_id = params.text_document.try_conv_with(&world)?;
+    let line_index = world.analysis().file_line_index(file_id)?;
+    let offset = params.position.conv_with(&line_index);
+    let file = world.analysis().file_syntax(file_id)?;
+    let action = match libeditor::on_eq_typed(&file, offset) {
+        None => return Ok(None),
+        Some(action) => action,
+    };
+    Ok(Some(action.edit.conv_with(&line_index)))
+}
+
 pub fn handle_execute_command(
     world: ServerWorld,
     mut params: req::ExecuteCommandParams,
diff --git a/crates/server/src/main_loop/mod.rs b/crates/server/src/main_loop/mod.rs
index da1121cb4..accb13878 100644
--- a/crates/server/src/main_loop/mod.rs
+++ b/crates/server/src/main_loop/mod.rs
@@ -31,6 +31,7 @@ use {
         handle_completion,
         handle_runnables,
         handle_decorations,
+        handle_on_type_formatting,
     },
 };
 
@@ -161,6 +162,9 @@ fn on_request(
     handle_request_on_threadpool::<req::DecorationsRequest>(
         &mut req, pool, world, sender, handle_decorations,
     )?;
+    handle_request_on_threadpool::<req::OnTypeFormatting>(
+        &mut req, pool, world, sender, handle_on_type_formatting,
+    )?;
     dispatch::handle_request::<req::ExecuteCommand, _>(&mut req, |params, resp| {
         io.send(RawMsg::Response(resp.into_response(Ok(None))?));
 
diff --git a/crates/server/src/req.rs b/crates/server/src/req.rs
index 999fdb7c2..881069b1f 100644
--- a/crates/server/src/req.rs
+++ b/crates/server/src/req.rs
@@ -14,6 +14,7 @@ pub use languageserver_types::{
     TextDocumentPositionParams,
     TextEdit,
     CompletionParams, CompletionResponse,
+    DocumentOnTypeFormattingParams,
 };