late final solution to the var problem in Dart

var_problem_late_final_solution.dart

void main() {
  final list = <int>[1, 2, 3, 4, 2, -1, 5];
  final maxValue = 12;
  
  late final int sum;
  {
    var _sum = 0;
    for(final val in list) {
      _sum += val;
    }
    if(_sum > maxValue) {
      _sum = maxValue;
    }
    sum = _sum;
  }
  
  /// ... more code that uses `sum` ...
}