code: private static Context getContextForArrowFunctionBody(Context context) {
      return context.inForInInitClause()
          ? Context.START_OF_ARROW_FN_IN_FOR_INIT
          : Context.START_OF_ARROW_FN_BODY;
    }
docs: If we're at the start of an arrow function body, we need parentheses around object literals and
  object patterns. We also must also pass the IN_FOR_INIT_CLAUSE flag into subexpressions.