anchor.diff:    }
   
     @override
  -  Type _visit(Harness h) {
  +  Type _visit(Harness h, Type context) {
       return h._typeAnalyzer
           .analyzeTypeTest(this, target, type, isInverted: isInverted);
     }
  
positive.code:     flow.doStatement_end(condition);
    }
  
    Type analyzeExpression(Expression expression) {
      return dispatchExpression(expression);
    }
  
    void analyzeExpressionStatement(Expression expression) {
  
negative.code:   }
  
    @override
    Type _visit(Harness h, Type context) {
      return h._typeAnalyzer.analyzeLogicalNot(this, operand);
    }
  }
  