Method ReportErrorAt

parser/parser.cc:192–194

  }

  Expr ReportErrorAt(const Expr& expr, absl::string_view message) override {
    return ReportError(GetSourceRange(expr.id()), message);
  }

  SourceRange GetSourceRange(int64_t id) const {
    if (auto it = positions_.find(id); it != positions_.end()) {