feat(els): add goto implementation

crates/els/README.md

@@ -13,7 +13,7 @@ ELS is a language server for the [Erg](https://github.com/erg-lang/erg) programm
 - [x] Diagnostics
 - [x] Hover
 - [x] Go to definition
-- [ ] Go to implementation
+- [x] Go to implementation
 - [x] Find references
 - [x] Renaming
 - [x] Inlay hint

crates/els/channels.rs

@@ -6,9 +6,10 @@ use erg_compiler::erg_parser::parse::Parsable;
 use lsp_types::request::{
     CallHierarchyIncomingCalls, CallHierarchyOutgoingCalls, CallHierarchyPrepare,
     CodeActionRequest, CodeActionResolveRequest, CodeLensRequest, Completion,
-    DocumentSymbolRequest, ExecuteCommand, FoldingRangeRequest, GotoDefinition, HoverRequest,
-    InlayHintRequest, InlayHintResolveRequest, References, ResolveCompletionItem,
-    SemanticTokensFullRequest, SignatureHelpRequest, WillRenameFiles, WorkspaceSymbol,
+    DocumentSymbolRequest, ExecuteCommand, FoldingRangeRequest, GotoDefinition, GotoImplementation,
+    GotoImplementationParams, HoverRequest, InlayHintRequest, InlayHintResolveRequest, References,
+    ResolveCompletionItem, SemanticTokensFullRequest, SignatureHelpRequest, WillRenameFiles,
+    WorkspaceSymbol,
 };
 use lsp_types::{
     CallHierarchyIncomingCallsParams, CallHierarchyOutgoingCallsParams, CallHierarchyPrepareParams,
@@ -37,6 +38,7 @@ pub struct SendChannels {
     completion: mpsc::Sender<WorkerMessage<CompletionParams>>,
     resolve_completion: mpsc::Sender<WorkerMessage<CompletionItem>>,
     goto_definition: mpsc::Sender<WorkerMessage<GotoDefinitionParams>>,
+    goto_implementation: mpsc::Sender<WorkerMessage<GotoImplementationParams>>,
     semantic_tokens_full: mpsc::Sender<WorkerMessage<SemanticTokensParams>>,
     inlay_hint: mpsc::Sender<WorkerMessage<InlayHintParams>>,
     inlay_hint_resolve: mpsc::Sender<WorkerMessage<InlayHint>>,
@@ -62,6 +64,7 @@ impl SendChannels {
         let (tx_completion, rx_completion) = mpsc::channel();
         let (tx_resolve_completion, rx_resolve_completion) = mpsc::channel();
         let (tx_goto_definition, rx_goto_definition) = mpsc::channel();
+        let (tx_goto_implementation, rx_goto_implementation) = mpsc::channel();
         let (tx_semantic_tokens_full, rx_semantic_tokens_full) = mpsc::channel();
         let (tx_inlay_hint, rx_inlay_hint) = mpsc::channel();
         let (tx_inlay_hint_resolve, rx_inlay_hint_resolve) = mpsc::channel();
@@ -85,6 +88,7 @@ impl SendChannels {
                 completion: tx_completion,
                 resolve_completion: tx_resolve_completion,
                 goto_definition: tx_goto_definition,
+                goto_implementation: tx_goto_implementation,
                 semantic_tokens_full: tx_semantic_tokens_full,
                 inlay_hint: tx_inlay_hint,
                 inlay_hint_resolve: tx_inlay_hint_resolve,
@@ -108,6 +112,7 @@ impl SendChannels {
                 completion: rx_completion,
                 resolve_completion: rx_resolve_completion,
                 goto_definition: rx_goto_definition,
+                goto_implementation: rx_goto_implementation,
                 semantic_tokens_full: rx_semantic_tokens_full,
                 inlay_hint: rx_inlay_hint,
                 inlay_hint_resolve: rx_inlay_hint_resolve,
@@ -166,6 +171,7 @@ pub struct ReceiveChannels {
     pub(crate) completion: mpsc::Receiver<WorkerMessage<CompletionParams>>,
     pub(crate) resolve_completion: mpsc::Receiver<WorkerMessage<CompletionItem>>,
     pub(crate) goto_definition: mpsc::Receiver<WorkerMessage<GotoDefinitionParams>>,
+    pub(crate) goto_implementation: mpsc::Receiver<WorkerMessage<GotoImplementationParams>>,
     pub(crate) semantic_tokens_full: mpsc::Receiver<WorkerMessage<SemanticTokensParams>>,
     pub(crate) inlay_hint: mpsc::Receiver<WorkerMessage<InlayHintParams>>,
     pub(crate) inlay_hint_resolve: mpsc::Receiver<WorkerMessage<InlayHint>>,
@@ -212,6 +218,11 @@ macro_rules! impl_sendable {
 impl_sendable!(Completion, CompletionParams, completion);
 impl_sendable!(ResolveCompletionItem, CompletionItem, resolve_completion);
 impl_sendable!(GotoDefinition, GotoDefinitionParams, goto_definition);
+impl_sendable!(
+    GotoImplementation,
+    GotoImplementationParams,
+    goto_implementation
+);
 impl_sendable!(
     SemanticTokensFullRequest,
     SemanticTokensParams,

crates/els/definition.rs

@@ -4,11 +4,11 @@ use erg_compiler::artifact::BuildRunnable;
 use erg_compiler::context::register::PylyzerStatus;
 use erg_compiler::erg_parser::parse::Parsable;
 use erg_compiler::erg_parser::token::{Token, TokenCategory};
-use erg_compiler::hir::Expr;
+use erg_compiler::hir::{Def, Expr};
 use erg_compiler::ty::HasType;
 use erg_compiler::varinfo::VarInfo;
 
-use lsp_types::{GotoDefinitionParams, GotoDefinitionResponse, Url};
+use lsp_types::{GotoDefinitionParams, GotoDefinitionResponse, Location, Position, Url};
 
 use crate::server::{send_log, ELSResult, Server};
 use crate::util::{self, NormalizedUrl};
@@ -30,58 +30,51 @@ impl<Checker: BuildRunnable, Parser: Parsable> Server<Checker, Parser> {
         }
     }
 
-    fn get_definition_response(
+    pub(crate) fn get_definition_location(
         &self,
-        params: GotoDefinitionParams,
-    ) -> ELSResult<GotoDefinitionResponse> {
-        let uri = NormalizedUrl::new(params.text_document_position_params.text_document.uri);
-        let pos = params.text_document_position_params.position;
-        if let Some(token) = self.file_cache.get_symbol(&uri, pos) {
-            if let Some(vi) = self.get_definition(&uri, &token)? {
+        uri: &NormalizedUrl,
+        pos: Position,
+    ) -> ELSResult<Option<Location>> {
+        if let Some(token) = self.file_cache.get_symbol(uri, pos) {
+            if let Some(vi) = self.get_definition(uri, &token)? {
                 // If the target variable is an imported one, jump to the definition file.
                 // Else if the target variable is an alias, jump to the definition of it.
                 // `foo = import "foo"` => jump to `foo.er`
                 // `{x;} = import "foo"` => jump to `x` of `foo.er`
-                if vi.def_loc.module == Some(util::uri_to_path(&uri))
+                if vi.def_loc.module == Some(util::uri_to_path(uri))
                     && vi.def_loc.loc == token.loc()
                 {
-                    if let Some((_, Expr::Def(def))) = self.get_min_expr(&uri, pos, 0) {
+                    if let Some(def) = self.get_min::<Def>(uri, pos) {
                         if def.def_kind().is_import() {
                             if vi.t.is_module() {
                                 if let Some(path) = self
-                                    .get_local_ctx(&uri, pos)
+                                    .get_local_ctx(uri, pos)
                                     .first()
                                     .and_then(|ctx| ctx.get_path_with_mod_t(&vi.t))
                                 {
                                     let mod_uri = Url::from_file_path(path).unwrap();
-                                    let resp = GotoDefinitionResponse::Array(vec![
-                                        lsp_types::Location::new(
-                                            mod_uri,
-                                            lsp_types::Range::default(),
-                                        ),
-                                    ]);
-                                    return Ok(resp);
+                                    return Ok(Some(lsp_types::Location::new(
+                                        mod_uri,
+                                        lsp_types::Range::default(),
+                                    )));
                                 }
                             } else {
                                 // line of module member definitions may no longer match after the desugaring process
                                 let mod_t = def.body.ref_t();
                                 if let Some((_, vi)) = self
-                                    .get_local_ctx(&uri, pos)
+                                    .get_local_ctx(uri, pos)
                                     .first()
                                     .and_then(|ctx| ctx.get_mod_with_t(mod_t))
                                     .and_then(|mod_ctx| mod_ctx.get_var_info(token.inspect()))
                                 {
                                     let Some(path) = vi.def_loc.module.as_ref() else {
-                                        return Ok(GotoDefinitionResponse::Array(vec![]));
+                                        return Ok(None);
                                     };
                                     let def_uri = Url::from_file_path(path).unwrap();
-                                    let resp = GotoDefinitionResponse::Array(vec![
-                                        lsp_types::Location::new(
-                                            def_uri,
-                                            util::loc_to_range(vi.def_loc.loc).unwrap(),
-                                        ),
-                                    ]);
-                                    return Ok(resp);
+                                    return Ok(Some(lsp_types::Location::new(
+                                        def_uri,
+                                        util::loc_to_range(vi.def_loc.loc).unwrap(),
+                                    )));
                                 }
                             }
                         } else if let Expr::Accessor(acc) = def.body.block.last().unwrap() {
@@ -103,14 +96,11 @@ impl<Checker: BuildRunnable, Parser: Parsable> Server<Checker, Parser> {
                                         path.clone()
                                     };
                                     let def_uri = Url::from_file_path(def_file).unwrap();
-                                    let resp = GotoDefinitionResponse::Array(vec![
-                                        lsp_types::Location::new(def_uri, range),
-                                    ]);
-                                    return Ok(resp);
+                                    return Ok(Some(lsp_types::Location::new(def_uri, range)));
                                 }
                                 _ => {
                                     send_log("not found (maybe builtin)")?;
-                                    return Ok(GotoDefinitionResponse::Array(vec![]));
+                                    return Ok(None);
                                 }
                             }
                         }
@@ -119,21 +109,19 @@ impl<Checker: BuildRunnable, Parser: Parsable> Server<Checker, Parser> {
                 match (vi.def_loc.module, util::loc_to_range(vi.def_loc.loc)) {
                     (Some(path), Some(range)) => {
                         let def_uri = Url::from_file_path(path).unwrap();
-                        Ok(GotoDefinitionResponse::Array(vec![
-                            lsp_types::Location::new(def_uri, range),
-                        ]))
+                        Ok(Some(lsp_types::Location::new(def_uri, range)))
                     }
                     _ => {
                         send_log("not found (maybe builtin)")?;
-                        Ok(GotoDefinitionResponse::Array(vec![]))
+                        Ok(None)
                     }
                 }
             } else {
-                Ok(GotoDefinitionResponse::Array(vec![]))
+                Ok(None)
             }
         } else {
             send_log("lex error occurred")?;
-            Ok(GotoDefinitionResponse::Array(vec![]))
+            Ok(None)
         }
     }
 
@@ -142,7 +130,9 @@ impl<Checker: BuildRunnable, Parser: Parsable> Server<Checker, Parser> {
         params: GotoDefinitionParams,
     ) -> ELSResult<Option<GotoDefinitionResponse>> {
         send_log(format!("definition requested: {params:?}"))?;
-        let result = self.get_definition_response(params)?;
-        Ok(Some(result))
+        let uri = NormalizedUrl::new(params.text_document_position_params.text_document.uri);
+        let pos = params.text_document_position_params.position;
+        let result = self.get_definition_location(&uri, pos)?;
+        Ok(result.map(GotoDefinitionResponse::Scalar))
     }
 }

crates/els/implementation.rs

@@ -0,0 +1,39 @@
+use erg_compiler::artifact::BuildRunnable;
+use erg_compiler::erg_parser::parse::Parsable;
+use lsp_types::request::{GotoImplementationParams, GotoImplementationResponse};
+
+use crate::_log;
+use crate::server::{ELSResult, Server};
+use crate::util::{loc_to_pos, NormalizedUrl};
+
+impl<Checker: BuildRunnable, Parser: Parsable> Server<Checker, Parser> {
+    pub(crate) fn handle_goto_implementation(
+        &mut self,
+        params: GotoImplementationParams,
+    ) -> ELSResult<Option<GotoImplementationResponse>> {
+        _log!("implementation requested: {params:?}");
+        let uri = NormalizedUrl::new(params.text_document_position_params.text_document.uri);
+        let pos = params.text_document_position_params.position;
+        let Some(symbol) = self.file_cache.get_symbol(&uri, pos) else {
+            return Ok(None);
+        };
+        // {x #[ ← this is not the impl ]#;} = import "foo"
+        // print! x # ← symbol
+        if let Some(vi) = self.get_definition(&uri, &symbol)? {
+            let Some(uri) = vi
+                .def_loc
+                .module
+                .and_then(|p| NormalizedUrl::from_file_path(p).ok())
+            else {
+                return Ok(None);
+            };
+            let Some(pos) = loc_to_pos(vi.def_loc.loc) else {
+                return Ok(None);
+            };
+            if let Some(location) = self.get_definition_location(&uri, pos)? {
+                return Ok(Some(GotoImplementationResponse::Scalar(location)));
+            }
+        }
+        Ok(None)
+    }
+}

crates/els/lib.rs

@@ -11,6 +11,7 @@ mod file_cache;
 mod folding_range;
 mod hir_visitor;
 mod hover;
+mod implementation;
 mod inlay_hint;
 mod message;
 mod references;

crates/els/main.rs

@@ -11,6 +11,7 @@ mod file_cache;
 mod folding_range;
 mod hir_visitor;
 mod hover;
+mod implementation;
 mod inlay_hint;
 mod message;
 mod references;

crates/els/server.rs

@@ -29,19 +29,20 @@ use erg_compiler::ty::HasType;
 use lsp_types::request::{
     CallHierarchyIncomingCalls, CallHierarchyOutgoingCalls, CallHierarchyPrepare,
     CodeActionRequest, CodeActionResolveRequest, CodeLensRequest, Completion,
-    DocumentSymbolRequest, ExecuteCommand, FoldingRangeRequest, GotoDefinition, HoverRequest,
-    InlayHintRequest, InlayHintResolveRequest, References, Rename, Request, ResolveCompletionItem,
-    SemanticTokensFullRequest, SignatureHelpRequest, WillRenameFiles, WorkspaceSymbol,
+    DocumentSymbolRequest, ExecuteCommand, FoldingRangeRequest, GotoDefinition, GotoImplementation,
+    HoverRequest, InlayHintRequest, InlayHintResolveRequest, References, Rename, Request,
+    ResolveCompletionItem, SemanticTokensFullRequest, SignatureHelpRequest, WillRenameFiles,
+    WorkspaceSymbol,
 };
 use lsp_types::{
     CallHierarchyServerCapability, CodeActionKind, CodeActionOptions, CodeActionProviderCapability,
     CodeLensOptions, CompletionOptions, ConfigurationItem, ConfigurationParams,
     DidChangeTextDocumentParams, DidOpenTextDocumentParams, ExecuteCommandOptions,
-    FoldingRangeProviderCapability, HoverProviderCapability, InitializeParams, InitializeResult,
-    InlayHintOptions, InlayHintServerCapabilities, OneOf, Position, SemanticTokenType,
-    SemanticTokensFullOptions, SemanticTokensLegend, SemanticTokensOptions,
-    SemanticTokensServerCapabilities, ServerCapabilities, SignatureHelpOptions,
-    WorkDoneProgressOptions,
+    FoldingRangeProviderCapability, HoverProviderCapability, ImplementationProviderCapability,
+    InitializeParams, InitializeResult, InlayHintOptions, InlayHintServerCapabilities, OneOf,
+    Position, SemanticTokenType, SemanticTokensFullOptions, SemanticTokensLegend,
+    SemanticTokensOptions, SemanticTokensServerCapabilities, ServerCapabilities,
+    SignatureHelpOptions, WorkDoneProgressOptions,
 };
 
 use serde::{Deserialize, Serialize};
@@ -430,6 +431,7 @@ impl<Checker: BuildRunnable, Parser: Parsable> Server<Checker, Parser> {
         capabilities.rename_provider = Some(OneOf::Left(true));
         capabilities.references_provider = Some(OneOf::Left(true));
         capabilities.definition_provider = Some(OneOf::Left(true));
+        capabilities.implementation_provider = Some(ImplementationProviderCapability::Simple(true));
         capabilities.hover_provider = self
             .disabled_features
             .contains(&DefaultFeatures::Hover)
@@ -538,6 +540,10 @@ impl<Checker: BuildRunnable, Parser: Parsable> Server<Checker, Parser> {
             receivers.goto_definition,
             Self::handle_goto_definition,
         );
+        self.start_service::<GotoImplementation>(
+            receivers.goto_implementation,
+            Self::handle_goto_implementation,
+        );
         self.start_service::<SemanticTokensFullRequest>(
             receivers.semantic_tokens_full,
             Self::handle_semantic_tokens_full,
@@ -755,6 +761,7 @@ impl<Checker: BuildRunnable, Parser: Parsable> Server<Checker, Parser> {
             Completion::METHOD => self.parse_send::<Completion>(id, msg),
             ResolveCompletionItem::METHOD => self.parse_send::<ResolveCompletionItem>(id, msg),
             GotoDefinition::METHOD => self.parse_send::<GotoDefinition>(id, msg),
+            GotoImplementation::METHOD => self.parse_send::<GotoImplementation>(id, msg),
             HoverRequest::METHOD => self.parse_send::<HoverRequest>(id, msg),
             References::METHOD => self.parse_send::<References>(id, msg),
             SemanticTokensFullRequest::METHOD => {