3 files changed, 45 insertions, 2 deletions

diff --git a/crates/ra_lsp_server/src/caps.rs b/crates/ra_lsp_server/src/caps.rs
index 84c43bbec..b6436b646 100644
--- a/crates/ra_lsp_server/src/caps.rs
+++ b/crates/ra_lsp_server/src/caps.rs
@@ -2,7 +2,7 @@ use languageserver_types::{
     CodeActionProviderCapability, CompletionOptions, DocumentOnTypeFormattingOptions,
     ExecuteCommandOptions, FoldingRangeProviderCapability, ServerCapabilities,
     SignatureHelpOptions, TextDocumentSyncCapability, TextDocumentSyncKind,
-    TextDocumentSyncOptions,
+    TextDocumentSyncOptions, RenameProviderCapability, RenameOptions
 };
 
 pub fn server_capabilities() -> ServerCapabilities {
@@ -40,7 +40,9 @@ pub fn server_capabilities() -> ServerCapabilities {
             more_trigger_character: None,
         }),
         folding_range_provider: Some(FoldingRangeProviderCapability::Simple(true)),
-        rename_provider: None,
+        rename_provider: Some(RenameProviderCapability::Options(RenameOptions{
+            prepare_provider: Some(true)
+        })),
         color_provider: None,
         execute_command_provider: Some(ExecuteCommandOptions {
             commands: vec!["apply_code_action".to_string()],
diff --git a/crates/ra_lsp_server/src/main_loop/handlers.rs b/crates/ra_lsp_server/src/main_loop/handlers.rs
index 9b8d40eaa..3de440e1f 100644
--- a/crates/ra_lsp_server/src/main_loop/handlers.rs
+++ b/crates/ra_lsp_server/src/main_loop/handlers.rs
@@ -4,6 +4,7 @@ use languageserver_types::{
     CodeActionResponse, Command, CompletionItem, CompletionItemKind, Diagnostic,
     DiagnosticSeverity, DocumentSymbol, FoldingRange, FoldingRangeKind, FoldingRangeParams,
     InsertTextFormat, Location, Position, SymbolInformation, TextDocumentIdentifier, TextEdit,
+    RenameParams, WorkspaceEdit
 };
 use ra_analysis::{FileId, FoldKind, JobToken, Query, RunnableKind};
 use ra_syntax::text_utils::contains_offset_nonstrict;
@@ -17,6 +18,8 @@ use crate::{
     Result,
 };
 
+use std::collections::HashMap;
+
 pub fn handle_syntax_tree(
     world: ServerWorld,
     params: req::SyntaxTreeParams,
@@ -460,6 +463,43 @@ pub fn handle_signature_help(
     }
 }
 
+pub fn handle_rename(
+    world: ServerWorld,
+    params: RenameParams,
+    token: JobToken,
+) -> Result<Option<WorkspaceEdit>> {
+    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);
+
+    if params.new_name.is_empty() {
+        return Ok(None);
+    }
+
+    let refs = world.analysis().find_all_refs(file_id, offset, &token);
+    if refs.is_empty() {
+        return Ok(None);
+    }
+
+    let mut changes = HashMap::new();
+    for r in refs {
+        if let Ok(loc) = to_location(r.0, r.1, &world, &line_index) {
+            changes.entry(loc.uri).or_insert(Vec::new()).push(
+                TextEdit {
+                    range: loc.range,
+                    new_text: params.new_name.clone()
+                });
+        }
+    }
+
+    Ok(Some(WorkspaceEdit {
+        changes: Some(changes),
+
+        // TODO: return this instead if client/server support it. See #144
+        document_changes : None,
+    }))
+}
+
 pub fn handle_references(
     world: ServerWorld,
     params: req::ReferenceParams,
diff --git a/crates/ra_lsp_server/src/main_loop/mod.rs b/crates/ra_lsp_server/src/main_loop/mod.rs
index 7efec8a7a..236746447 100644
--- a/crates/ra_lsp_server/src/main_loop/mod.rs
+++ b/crates/ra_lsp_server/src/main_loop/mod.rs
@@ -248,6 +248,7 @@ fn on_request(
         .on::<req::CodeActionRequest>(handlers::handle_code_action)?
         .on::<req::FoldingRangeRequest>(handlers::handle_folding_range)?
         .on::<req::SignatureHelpRequest>(handlers::handle_signature_help)?
+        .on::<req::Rename>(handlers::handle_rename)?
         .on::<req::References>(handlers::handle_references)?
         .finish();
     match req {