anchor.diff:  
   import 'package:kernel/ast.dart' as ir;
   
  +import '../closure.dart';
   import '../common.dart';
   import '../common/codegen.dart' show CodegenRegistry, CodegenWorkItem;
   import '../common/names.dart';
  
positive.code:     }
      if (originTarget is FunctionElement) {
        target = kernel.functions[originTarget];
      } else if (originTarget is FieldElement) {
        target = kernel.fields[originTarget];
      }
  
negative.code:         type, kind, original.instructionType, reifiedType, original);
    }
  
    /// Builds a SSA graph for FunctionNodes, found in FunctionExpressions and
    /// Procedures.
    void buildFunctionNode(ir.FunctionNode functionNode) {
      openFunction();
      functionNode.body.accept(this);
      closeFunction();
    }
  
  