anchor.diff:  
     /// Return the range from the list of [ranges] that contains the given
     /// [index], or `null` if there is no such range.
  -  _IndexRange? _rangeContaining(List<_IndexRange> ranges, int index) {
  +  IndexRange? _rangeContaining(List<IndexRange> ranges, int index) {
       for (var range in ranges) {
         if (index >= range.lower && index <= range.upper) {
           return range;
  
positive.code:   /// invocation site.
    _Data(this.argumentList);
  }
  
  /// A range of indexes within a list.
  class _IndexRange {
    /// The index of the first element in the range.
    final int lower;
  
    /// The index of the last element in the range. This will be the same as the
    /// [lower] if there is a single element in the range.
    final int upper;
  
    /// Initialize a newly created range.
    _IndexRange(this.lower, this.upper);
  
    /// Return the number of indices in this range.
    int get count => upper - lower + 1;
  
    @override
    String toString() => '[$lower..$upper]';
  }
  
  extension on List<int> {
    Iterable<_IndexRange> get contiguousSubRanges sync* {
      if (isEmpty) {
        return;
      }
      var lower = this[0];
      var previous = lower;
      var index = 1;
      while (index < length) {
        var current = this[index];
        if (current == previous + 1) {
          previous = current;
        } else {
          yield _IndexRange(lower, previous);
          lower = previous = current;
        }
        index++;
      }
      yield _IndexRange(lower, previous);
    }
  }
  
negative.code: import 'package:analysis_server/src/services/correction/fix/data_driven/change.dart';
  import 'package:analysis_server/src/services/correction/fix/data_driven/code_template.dart';
  import 'package:analysis_server/src/services/correction/fix/data_driven/parameter_reference.dart';
  import 'package:analysis_server/src/utilities/index_range.dart';
  import 'package:analyzer/dart/ast/ast.dart';
  import 'package:analyzer_plugin/utilities/change_builder/change_builder_dart.dart';
  import 'package:analyzer_plugin/utilities/range_factory.dart';
  