anchor.diff:  
     /// Creates a new zero-length prefix with initial [indent] whose suffix is
     /// the entire line.
  -  LinePrefix(int indent)
  -      : this._(0, {}, indent, new NestingStack());
  +  LinePrefix(int indent) : this._(0, {}, indent, new NestingStack());
   
  -  LinePrefix._(this.length, this.ruleValues, this._indent,
  -      this._nesting) {
  -    assert(_nesting != null);
  -  }
  +  LinePrefix._(this.length, this.ruleValues, this._indent, this._nesting);
   
     bool operator ==(other) {
       if (other is! LinePrefix) return false;
  
positive.code:           .map((key) => "$key:${ruleValues[key]}")
            .join(" ");
  
        result +=" rules $rules";
      }
      return result;
    }
  
negative.code: // for details. All rights reserved. Use of this source code is governed by a
  // BSD-style license that can be found in the LICENSE file.
  
  library dart_style.src.line_prefix;
  
  import 'chunk.dart';
  import 'nesting.dart';
  