Add support for renaming local variables

crates/ark/src/lsp.rs

@@ -32,6 +32,7 @@ pub mod main_loop;
 pub mod markdown;
 
 pub mod find_references;
+pub mod rename;
 pub mod selection_range;
 pub mod signature_help;
 pub mod state;

crates/ark/src/lsp/backend.rs

@@ -80,7 +80,10 @@ macro_rules! cast_response {
             },
             RequestResponse::Result(Err(err)) => match err {
                 LspError::JsonRpc(err) => Err(err),
-                LspError::Anyhow(err) => Err(new_jsonrpc_error(format!("{err:?}"))),
+                // `{err}` (Display) prints just the message. `{err:?}` (Debug)
+                // would include the captured backtrace when `RUST_BACKTRACE`
+                // is set, which then surfaces in the client's error popup.
+                LspError::Anyhow(err) => Err(new_jsonrpc_error(format!("{err}"))),
             },
             RequestResponse::Crashed(err) => {
                 // Notify user that the LSP has crashed and is no longer active
@@ -153,6 +156,8 @@ pub(crate) enum LspRequest {
     GotoImplementation(GotoImplementationParams),
     SelectionRange(SelectionRangeParams),
     References(ReferenceParams),
+    PrepareRename(TextDocumentPositionParams),
+    Rename(RenameParams),
     StatementRange(StatementRangeParams),
     HelpTopic(HelpTopicParams),
     OnTypeFormatting(DocumentOnTypeFormattingParams),
@@ -177,6 +182,8 @@ pub(crate) enum LspResponse {
     GotoImplementation(Option<GotoImplementationResponse>),
     SelectionRange(Option<Vec<SelectionRange>>),
     References(Option<Vec<Location>>),
+    PrepareRename(Option<PrepareRenameResponse>),
+    Rename(Option<WorkspaceEdit>),
     StatementRange(Option<StatementRangeResponse>),
     HelpTopic(Option<HelpTopicResponse>),
     OnTypeFormatting(Option<Vec<TextEdit>>),
@@ -431,6 +438,25 @@ impl LanguageServer for Backend {
         )
     }
 
+    async fn prepare_rename(
+        &self,
+        params: TextDocumentPositionParams,
+    ) -> Result<Option<PrepareRenameResponse>> {
+        cast_response!(
+            self,
+            self.request(LspRequest::PrepareRename(params)).await,
+            LspResponse::PrepareRename
+        )
+    }
+
+    async fn rename(&self, params: RenameParams) -> Result<Option<WorkspaceEdit>> {
+        cast_response!(
+            self,
+            self.request(LspRequest::Rename(params)).await,
+            LspResponse::Rename
+        )
+    }
+
     async fn on_type_formatting(
         &self,
         params: DocumentOnTypeFormattingParams,

crates/ark/src/lsp/handlers.rs

@@ -26,13 +26,16 @@ use tower_lsp::lsp_types::HoverContents;
 use tower_lsp::lsp_types::HoverParams;
 use tower_lsp::lsp_types::Location;
 use tower_lsp::lsp_types::MessageType;
+use tower_lsp::lsp_types::PrepareRenameResponse;
 use tower_lsp::lsp_types::ReferenceParams;
 use tower_lsp::lsp_types::Registration;
+use tower_lsp::lsp_types::RenameParams;
 use tower_lsp::lsp_types::SelectionRange;
 use tower_lsp::lsp_types::SelectionRangeParams;
 use tower_lsp::lsp_types::SignatureHelp;
 use tower_lsp::lsp_types::SignatureHelpParams;
 use tower_lsp::lsp_types::SymbolInformation;
+use tower_lsp::lsp_types::TextDocumentPositionParams;
 use tower_lsp::lsp_types::TextEdit;
 use tower_lsp::lsp_types::WorkspaceEdit;
 use tower_lsp::lsp_types::WorkspaceSymbolParams;
@@ -58,6 +61,7 @@ use crate::lsp::indent::indent_edit;
 use crate::lsp::input_boundaries::InputBoundariesParams;
 use crate::lsp::input_boundaries::InputBoundariesResponse;
 use crate::lsp::main_loop::LspState;
+use crate::lsp::rename;
 use crate::lsp::selection_range::convert_selection_range_from_tree_sitter_to_lsp;
 use crate::lsp::selection_range::selection_range;
 use crate::lsp::signature_help::r_signature_help;
@@ -327,6 +331,25 @@ pub(crate) fn handle_references(
     }
 }
 
+#[tracing::instrument(level = "info", skip_all)]
+pub(crate) fn handle_prepare_rename(
+    params: TextDocumentPositionParams,
+    state: &WorldState,
+) -> LspResult<Option<PrepareRenameResponse>> {
+    // Don't propagate errors to the frontend
+    Ok(rename::prepare_rename(params, state).log_err().flatten())
+}
+
+#[tracing::instrument(level = "info", skip_all)]
+pub(crate) fn handle_rename(
+    params: RenameParams,
+    state: &WorldState,
+) -> LspResult<Option<WorkspaceEdit>> {
+    // Propagate error to the frontend (unlike `prepare_rename()`) to give
+    // actionable feedback to the user
+    Ok(rename::rename(params, state)?)
+}
+
 #[tracing::instrument(level = "info", skip_all)]
 pub(crate) fn handle_statement_range(
     params: StatementRangeParams,

crates/ark/src/lsp/main_loop.rs

@@ -370,6 +370,12 @@ impl GlobalState {
                         LspRequest::References(params) => {
                             respond(tx, || handlers::handle_references(params, &self.world), LspResponse::References)?;
                         },
+                        LspRequest::PrepareRename(params) => {
+                            respond(tx, || handlers::handle_prepare_rename(params, &self.world), LspResponse::PrepareRename)?;
+                        },
+                        LspRequest::Rename(params) => {
+                            respond(tx, || handlers::handle_rename(params, &self.world), LspResponse::Rename)?;
+                        },
                         LspRequest::StatementRange(params) => {
                             respond(tx, || handlers::handle_statement_range(params, &self.world), LspResponse::StatementRange)?;
                         },
@@ -490,7 +496,12 @@ fn respond<T>(
     let out = match response {
         RequestResponse::Result(Ok(_)) => Ok(()),
         RequestResponse::Result(Err(ref error)) => {
-            Err(anyhow!("Error while handling request:\n{error:?}"))
+            // The error has already been sent to the client on `response_tx`
+            // as a jsonrpc error, so the user sees the popup. Log here at
+            // info level (with `{:?}` for the full debug format including a
+            // backtrace) so server logs keep diagnostic context.
+            lsp::log_info!("Error while handling request:\n{error:?}");
+            Ok(())
         },
         RequestResponse::Crashed(ref error) => {
             Err(anyhow!("Crashed while handling request:\n{error:?}"))

crates/ark/src/lsp/rename.rs

@@ -0,0 +1,83 @@
+use std::collections::HashMap;
+
+use aether_lsp_utils::proto::from_proto;
+use aether_lsp_utils::proto::to_proto;
+use tower_lsp::lsp_types;
+use tower_lsp::lsp_types::PrepareRenameResponse;
+use tower_lsp::lsp_types::RenameParams;
+use tower_lsp::lsp_types::TextDocumentPositionParams;
+use tower_lsp::lsp_types::TextEdit;
+use tower_lsp::lsp_types::WorkspaceEdit;
+
+use crate::lsp::state::WorldState;
+
+pub(crate) fn prepare_rename(
+    params: TextDocumentPositionParams,
+    state: &WorldState,
+) -> anyhow::Result<Option<PrepareRenameResponse>> {
+    let uri = params.text_document.uri;
+    let position = params.position;
+    let document = state.get_document(&uri)?;
+
+    let offset = from_proto::offset_from_position(
+        position,
+        &document.line_index,
+        document.position_encoding,
+    )?;
+    let index = document.semantic_index();
+    let tree = document.syntax()?;
+    let pos = oak_ide::FileOffset { file: uri, offset };
+
+    let Some((range, placeholder)) = oak_ide::prepare_rename(&index, &tree, &pos) else {
+        return Ok(None);
+    };
+
+    let range = to_proto::range(range, &document.line_index, document.position_encoding)?;
+    Ok(Some(PrepareRenameResponse::RangeWithPlaceholder {
+        range,
+        placeholder,
+    }))
+}
+
+pub(crate) fn rename(
+    params: RenameParams,
+    state: &WorldState,
+) -> anyhow::Result<Option<WorkspaceEdit>> {
+    let uri = params.text_document_position.text_document.uri;
+    let position = params.text_document_position.position;
+    let new_name = params.new_name;
+    let document = state.get_document(&uri)?;
+
+    let offset = from_proto::offset_from_position(
+        position,
+        &document.line_index,
+        document.position_encoding,
+    )?;
+    let index = document.semantic_index();
+    let root = document.syntax()?;
+    let pos = oak_ide::FileOffset {
+        file: uri.clone(),
+        offset,
+    };
+
+    let targets = oak_ide::rename(&index, &root, &pos, &new_name)?;
+
+    // All edits target the current file (intra-file rename).
+    let mut edits: Vec<TextEdit> = Vec::with_capacity(targets.ranges.len());
+    for r in targets.ranges {
+        let range = to_proto::range(r.range, &document.line_index, document.position_encoding)?;
+        edits.push(TextEdit {
+            range,
+            new_text: targets.new_text.clone(),
+        });
+    }
+
+    let mut changes: HashMap<lsp_types::Url, Vec<TextEdit>> = HashMap::new();
+    changes.insert(uri, edits);
+
+    Ok(Some(WorkspaceEdit {
+        changes: Some(changes),
+        document_changes: None,
+        change_annotations: None,
+    }))
+}

crates/ark/src/lsp/state_handlers.rs

@@ -32,6 +32,7 @@ use tower_lsp::lsp_types::InitializeParams;
 use tower_lsp::lsp_types::InitializeResult;
 use tower_lsp::lsp_types::OneOf;
 use tower_lsp::lsp_types::RenameFilesParams;
+use tower_lsp::lsp_types::RenameOptions;
 use tower_lsp::lsp_types::SelectionRangeProviderCapability;
 use tower_lsp::lsp_types::ServerCapabilities;
 use tower_lsp::lsp_types::ServerInfo;
@@ -164,6 +165,12 @@ pub(crate) fn initialize(
             type_definition_provider: None,
             implementation_provider: Some(ImplementationProviderCapability::Simple(true)),
             references_provider: Some(OneOf::Left(true)),
+            rename_provider: Some(OneOf::Right(RenameOptions {
+                prepare_provider: Some(true),
+                work_done_progress_options: WorkDoneProgressOptions {
+                    work_done_progress: None,
+                },
+            })),
             document_symbol_provider: Some(OneOf::Left(true)),
             folding_range_provider: Some(FoldingRangeProviderCapability::Simple(true)),
             workspace_symbol_provider: Some(OneOf::Left(true)),

crates/ark/src/lsp/tests.rs

@@ -1,2 +1,4 @@
 mod find_references;
 mod goto_definition;
+mod rename;
+mod utils;

crates/ark/src/lsp/tests/find_references.rs

@@ -3,9 +3,10 @@ use tower_lsp::lsp_types::Location;
 use tower_lsp::lsp_types::ReferenceContext;
 use tower_lsp::lsp_types::ReferenceParams;
 
+use super::utils::make_state;
+use super::utils::range;
 use crate::lsp::document::Document;
 use crate::lsp::find_references::find_references;
-use crate::lsp::state::WorldState;
 use crate::lsp::util::test_path;
 
 fn make_params(
@@ -27,19 +28,6 @@ fn make_params(
     }
 }
 
-fn make_state(uri: &lsp_types::Url, doc: &Document) -> WorldState {
-    let mut state = WorldState::default();
-    state.documents.insert(uri.clone(), doc.clone());
-    state
-}
-
-fn range(start: (u32, u32), end: (u32, u32)) -> lsp_types::Range {
-    lsp_types::Range {
-        start: lsp_types::Position::new(start.0, start.1),
-        end: lsp_types::Position::new(end.0, end.1),
-    }
-}
-
 #[test]
 fn test_intra_file_use_and_def() {
     let code = "foo <- 1\nfoo + foo\n";