Implement TextDocumentDeclaration

CHANGES.md

@@ -4,6 +4,9 @@
 
 - Add keyword completion
 
+- Add go to declaration functionality to jump to a value's specification in a
+  .mli file (#294)
+
 ## Fixes
 
 - #245: correctly use mutexes on OpenBSD (#264)

ocaml-lsp-server/src/ocaml_lsp_server.ml

@@ -44,9 +44,10 @@ let initialize_info : InitializeResult.t =
         ]
     in
     ServerCapabilities.create ~textDocumentSync ~hoverProvider:(`Bool true)
-      ~definitionProvider:(`Bool true) ~typeDefinitionProvider:(`Bool true)
-      ~completionProvider ~codeActionProvider ~codeLensProvider
-      ~referencesProvider:(`Bool true) ~documentHighlightProvider:(`Bool true)
+      ~declarationProvider:(`Bool true) ~definitionProvider:(`Bool true)
+      ~typeDefinitionProvider:(`Bool true) ~completionProvider
+      ~codeActionProvider ~codeLensProvider ~referencesProvider:(`Bool true)
+      ~documentHighlightProvider:(`Bool true)
       ~documentFormattingProvider:(`Bool true)
       ~selectionRangeProvider:(`Bool true) ~documentSymbolProvider:(`Bool true)
       ~foldingRangeProvider:(`Bool true) ~experimental ~renameProvider ()
@@ -550,7 +551,10 @@ let ocaml_on_request :
     let open Fiber.O in
     let+ symbols = Document_symbol.run client_capabilities doc uri in
     Ok (Some symbols, state)
-  | Client_request.TextDocumentDeclaration _ -> Fiber.return @@ Ok (None, state)
+  | Client_request.TextDocumentDeclaration { textDocument = { uri }; position }
+    ->
+    definition_query state uri position (fun pos ->
+        Query_protocol.Locate (None, `MLI, pos))
   | Client_request.TextDocumentDefinition { textDocument = { uri }; position }
     ->
     definition_query state uri position (fun pos ->

ocaml-lsp-server/test/e2e/__tests__/declaration_files/dune

@@ -0,0 +1,2 @@
+(library
+ (name declaration_files))

ocaml-lsp-server/test/e2e/__tests__/declaration_files/dune-project

@@ -0,0 +1 @@
+(lang dune 2.5)

ocaml-lsp-server/test/e2e/__tests__/declaration_files/lib.ml

@@ -0,0 +1 @@
+let x = 1

ocaml-lsp-server/test/e2e/__tests__/declaration_files/lib.mli

@@ -0,0 +1 @@
+val x : int

ocaml-lsp-server/test/e2e/__tests__/declaration_files/main.ml

@@ -0,0 +1 @@
+let y = Lib.x

ocaml-lsp-server/test/e2e/__tests__/textDocument-declaration.test.ts

@@ -0,0 +1,71 @@
+import { promises as fs } from "fs";
+import * as path from "path";
+import * as child_process from "child_process";
+import * as LanguageServer from "./../src/LanguageServer";
+import * as Types from "vscode-languageserver-types";
+import { testUri, toEqualUri } from "./../src/LanguageServer";
+expect.extend({
+  toEqualUri,
+});
+declare global {
+  namespace jest {
+    interface Matchers<R> {
+      toEqualUri(uri: string): R;
+    }
+  }
+}
+
+describe("textDocument/declaration", () => {
+  let languageServer = null;
+
+  let testWorkspacePath = path.join(__dirname, "declaration_files/");
+
+  let createPathForFile = (filename: string) =>
+    path.join(testWorkspacePath, filename);
+
+  beforeEach(async () => {
+    languageServer = await LanguageServer.startAndInitialize();
+  });
+
+  afterEach(async () => {
+    await LanguageServer.exit(languageServer);
+    languageServer = null;
+  });
+
+  async function openDocument(filepath) {
+    let source = await fs.readFile(filepath);
+    await languageServer.sendNotification("textDocument/didOpen", {
+      textDocument: Types.TextDocumentItem.create(
+        testUri(filepath),
+        "ocaml",
+        0,
+        source.toString(),
+      ),
+    });
+  }
+
+  async function queryDeclaration(filepath, position) {
+    return await languageServer.sendRequest("textDocument/declaration", {
+      textDocument: Types.TextDocumentIdentifier.create(testUri(filepath)),
+      position,
+    });
+  }
+
+  it("returns location of a declaration", async () => {
+    child_process.execSync("dune build", { cwd: testWorkspacePath });
+
+    await openDocument(createPathForFile("main.ml"));
+
+    let result = await queryDeclaration(
+      createPathForFile("main.ml"),
+      Types.Position.create(0, 13),
+    );
+
+    expect(result.length).toBe(1);
+    expect(result[0].range).toMatchObject({
+      end: { character: 0, line: 0 },
+      start: { character: 0, line: 0 },
+    });
+    expect(result[0].uri).toEqualUri(testUri(createPathForFile("lib.ml")));
+  });
+});