6 files changed, 150 insertions, 2 deletions

diff --git a/cli/lsp/capabilities.rs b/cli/lsp/capabilities.rs
index e05cc27b8..8f17a6aff 100644
--- a/cli/lsp/capabilities.rs
+++ b/cli/lsp/capabilities.rs
@@ -27,6 +27,7 @@ use lspower::lsp::SignatureHelpOptions;
 use lspower::lsp::TextDocumentSyncCapability;
 use lspower::lsp::TextDocumentSyncKind;
 use lspower::lsp::TextDocumentSyncOptions;
+use lspower::lsp::TypeDefinitionProviderCapability;
 use lspower::lsp::WorkDoneProgressOptions;
 use lspower::lsp::WorkspaceFoldersServerCapabilities;
 use lspower::lsp::WorkspaceServerCapabilities;
@@ -109,7 +110,9 @@ pub fn server_capabilities(
     }),
     declaration_provider: None,
     definition_provider: Some(OneOf::Left(true)),
-    type_definition_provider: None,
+    type_definition_provider: Some(TypeDefinitionProviderCapability::Simple(
+      true,
+    )),
     implementation_provider: Some(ImplementationProviderCapability::Simple(
       true,
     )),
diff --git a/cli/lsp/language_server.rs b/cli/lsp/language_server.rs
index fb2b04214..a0d0ee0ad 100644
--- a/cli/lsp/language_server.rs
+++ b/cli/lsp/language_server.rs
@@ -1622,6 +1622,54 @@ impl Inner {
     }
   }
 
+  async fn goto_type_definition(
+    &mut self,
+    params: GotoTypeDefinitionParams,
+  ) -> LspResult<Option<GotoTypeDefinitionResponse>> {
+    let specifier = self
+      .url_map
+      .normalize_url(&params.text_document_position_params.text_document.uri);
+    if !self.is_diagnosable(&specifier)
+      || !self.config.specifier_enabled(&specifier)
+    {
+      return Ok(None);
+    }
+
+    let mark = self.performance.mark("goto_definition", Some(&params));
+    let asset_or_doc = self.get_cached_asset_or_document(&specifier)?;
+    let line_index = asset_or_doc.line_index();
+    let req = tsc::RequestMethod::GetTypeDefinition {
+      specifier,
+      position: line_index
+        .offset_tsc(params.text_document_position_params.position)?,
+    };
+    let maybe_definition_info: Option<Vec<tsc::DefinitionInfo>> = self
+      .ts_server
+      .request(self.snapshot()?, req)
+      .await
+      .map_err(|err| {
+        error!("Unable to get type definition from TypeScript: {}", err);
+        LspError::internal_error()
+      })?;
+
+    let response = if let Some(definition_info) = maybe_definition_info {
+      let mut location_links = Vec::new();
+      for info in definition_info {
+        if let Some(link) =
+          info.document_span.to_link(line_index.clone(), self).await
+        {
+          location_links.push(link);
+        }
+      }
+      Some(GotoTypeDefinitionResponse::Link(location_links))
+    } else {
+      None
+    };
+
+    self.performance.measure(mark);
+    Ok(response)
+  }
+
   async fn completion(
     &mut self,
     params: CompletionParams,
@@ -2428,6 +2476,13 @@ impl lspower::LanguageServer for LanguageServer {
     self.0.lock().await.goto_definition(params).await
   }
 
+  async fn goto_type_definition(
+    &self,
+    params: GotoTypeDefinitionParams,
+  ) -> LspResult<Option<GotoTypeDefinitionResponse>> {
+    self.0.lock().await.goto_type_definition(params).await
+  }
+
   async fn completion(
     &self,
     params: CompletionParams,
diff --git a/cli/lsp/tsc.rs b/cli/lsp/tsc.rs
index e56b7ab68..9647a79fc 100644
--- a/cli/lsp/tsc.rs
+++ b/cli/lsp/tsc.rs
@@ -2769,6 +2769,11 @@ pub enum RequestMethod {
   GetSmartSelectionRange((ModuleSpecifier, u32)),
   /// Get the diagnostic codes that support some form of code fix.
   GetSupportedCodeFixes,
+  /// Get the type definition information for a specific position.
+  GetTypeDefinition {
+    specifier: ModuleSpecifier,
+    position: u32,
+  },
   /// Resolve a call hierarchy item for a specific position.
   PrepareCallHierarchy((ModuleSpecifier, u32)),
   /// Resolve incoming call hierarchy items for a specific position.
@@ -2811,7 +2816,7 @@ impl RequestMethod {
         "id": id,
         "method": "getApplicableRefactors",
         "specifier": state.denormalize_specifier(specifier),
-        "range": { "pos": span.start, "end": span.start + span.length},
+        "range": { "pos": span.start, "end": span.start + span.length },
         "kind": kind,
       }),
       RequestMethod::GetEditsForRefactor((
@@ -2950,6 +2955,15 @@ impl RequestMethod {
         "id": id,
         "method": "getSupportedCodeFixes",
       }),
+      RequestMethod::GetTypeDefinition {
+        specifier,
+        position,
+      } => json!({
+        "id": id,
+        "method": "getTypeDefinition",
+        "specifier": state.denormalize_specifier(specifier),
+        "position": position
+      }),
       RequestMethod::PrepareCallHierarchy((specifier, position)) => {
         json!({
           "id": id,
diff --git a/cli/tests/integration/lsp_tests.rs b/cli/tests/integration/lsp_tests.rs
index 8e7de0286..3d55ac28c 100644
--- a/cli/tests/integration/lsp_tests.rs
+++ b/cli/tests/integration/lsp_tests.rs
@@ -1267,6 +1267,66 @@ fn lsp_hover_typescript_types() {
 }
 
 #[test]
+fn lsp_goto_type_definition() {
+  let mut client = init("initialize_params.json");
+  did_open(
+    &mut client,
+    json!({
+      "textDocument": {
+        "uri": "file:///a/file.ts",
+        "languageId": "typescript",
+        "version": 1,
+        "text": "interface A {\n  a: string;\n}\n\nexport class B implements A {\n  a = \"a\";\n  log() {\n    console.log(this.a);\n  }\n}\n\nconst b = new B();\nb;\n",
+      }
+    }),
+  );
+  let (maybe_res, maybe_error) = client
+    .write_request::<_, _, Value>(
+      "textDocument/typeDefinition",
+      json!({
+        "textDocument": {
+          "uri": "file:///a/file.ts"
+        },
+        "position": {
+          "line": 12,
+          "character": 1
+        }
+      }),
+    )
+    .unwrap();
+  assert!(maybe_error.is_none());
+  assert_eq!(
+    maybe_res,
+    Some(json!([
+      {
+        "targetUri": "file:///a/file.ts",
+        "targetRange": {
+          "start": {
+            "line": 4,
+            "character": 0
+          },
+          "end": {
+            "line": 9,
+            "character": 1
+          }
+        },
+        "targetSelectionRange": {
+          "start": {
+            "line": 4,
+            "character": 13
+          },
+          "end": {
+            "line": 4,
+            "character": 14
+          }
+        }
+      }
+    ]))
+  );
+  shutdown(&mut client);
+}
+
+#[test]
 fn lsp_call_hierarchy() {
   let mut client = init("initialize_params.json");
   did_open(
diff --git a/cli/tsc/99_main_compiler.js b/cli/tsc/99_main_compiler.js
index 1b3999bf9..d309956cb 100644
--- a/cli/tsc/99_main_compiler.js
+++ b/cli/tsc/99_main_compiler.js
@@ -810,6 +810,15 @@ delete Object.prototype.__proto__;
           ts.getSupportedCodeFixes(),
         );
       }
+      case "getTypeDefinition": {
+        return respond(
+          id,
+          languageService.getTypeDefinitionAtPosition(
+            request.specifier,
+            request.position,
+          ),
+        );
+      }
       case "prepareCallHierarchy": {
         return respond(
           id,
diff --git a/cli/tsc/compiler.d.ts b/cli/tsc/compiler.d.ts
index 8e6b6d417..d206c0b6b 100644
--- a/cli/tsc/compiler.d.ts
+++ b/cli/tsc/compiler.d.ts
@@ -66,6 +66,7 @@ declare global {
     | GetSignatureHelpItemsRequest
     | GetSmartSelectionRange
     | GetSupportedCodeFixes
+    | GetTypeDefinitionRequest
     | PrepareCallHierarchy
     | ProvideCallHierarchyIncomingCalls
     | ProvideCallHierarchyOutgoingCalls;
@@ -220,6 +221,12 @@ declare global {
     method: "getSupportedCodeFixes";
   }
 
+  interface GetTypeDefinitionRequest extends BaseLanguageServerRequest {
+    method: "getTypeDefinition";
+    specifier: string;
+    position: number;
+  }
+
   interface PrepareCallHierarchy extends BaseLanguageServerRequest {
     method: "prepareCallHierarchy";
     specifier: string;