anchor.diff:          _current.write(variable, writtenType, newSsaNode, typeOperations);
     }
   
  +  @override
     void _dumpState() {
       print('  current: $_current');
       print('  expressionWithInfo: $_expressionWithInfo');
  
positive.code: class FlowAnalysisDebug<Node extends Object, Statement extends Node,
          Expression extends Object, Variable extends Object, Type extends Object>
      implements FlowAnalysis<Node, Statement, Expression, Variable, Type> {
    _FlowAnalysisImpl<Node, Statement, Expression, Variable, Type> _wrapped;
  
    bool _exceptionOccurred = false;
  
  
negative.code:   /// necessary; in this case, [viaInitializer] should be `true`.
    void write(
        Variable variable, Type writtenType, Expression? writtenExpression);
  
    /// Prints out a summary of the current state of flow analysis, intended for
    /// debugging use only.
    void _dumpState();
  }
  
  /// Alternate implementation of [FlowAnalysis] that prints out inputs and output
  