anchor.diff:      node.accept(_AssignedVariablesVisitor(assignedVariables));
   
       return FlowAnalysisHelper._(
  -        _NodeOperations(),
  +        const AnalyzerNodeOperations(),
           _TypeSystemTypeOperations(typeSystem),
           assignedVariables,
           retainDataForTesting ? FlowAnalysisResult() : null);
  
positive.code: import 'package:analyzer/src/generated/variable_type_provider.dart';
  import 'package:front_end/src/fasta/flow_analysis/flow_analysis.dart';
  
  /// The helper for performing flow analysis during resolution.
  ///
  /// It contains related precomputed data, result, and non-trivial pieces of
  
negative.code:       flow = FlowAnalysis<Statement, Expression, VariableElement, DartType>(
          _nodeOperations,
          _typeOperations,
          AnalyzerFunctionBodyAccess(node),
        );
      }
  
  