message: Freeze event before firing
diff: @@ -215,8 +215,9 @@ export class TextDocuments {
  let td = event.textDocument;
  let document = TextDocument.create(td.uri, td.languageId, td.version, td.text);
  this._documents[td.uri] = document;
  - this._onDidOpen.fire({ document });
  - this._onDidChangeContent.fire(Object.freeze({ document }));
  + let toFire = Object.freeze({ document });
  + this._onDidOpen.fire(toFire);
  + this._onDidChangeContent.fire(toFire);
  });
  connection.onDidChangeTextDocument((event: DidChangeTextDocumentParams) => {
  let td = event.textDocument;
  