foo1.cs

    public void Run(ITreeNode element, ElementProblemAnalyzerData data, IHighlightingConsumer consumer)
    {
      var ifStatement = element as IIfStatement;
      if (ifStatement != null)
      {
        CheckCondition(ifStatement.Condition, consumer);
        return;
      }

      var whileStatement = element as IWhileStatement;
      if (whileStatement != null)
      {
        CheckCondition(whileStatement.Condition, consumer);
        return;
      }

      var doStatement = element as IDoStatement;
      if (doStatement != null)
      {
        CheckCondition(doStatement.Condition, consumer);
        return;
      }

      var forStatement = element as IForStatement;
      if (forStatement != null)
      {
        CheckCondition(forStatement.Condition, consumer);
        return;
      }

      var conditionalExpression = element as IConditionalTernaryExpression;
      if (conditionalExpression != null)
      {
        CheckCondition(conditionalExpression.ConditionOperand, consumer);
        return;
      }

      var exceptionFilterClause = element as IExceptionFilterClause;
      if (exceptionFilterClause != null)
      {
        CheckCondition(exceptionFilterClause.Condition, consumer);
        return;
      }

      var patternGuardClause = element as IPatternGuardClause;
      if (patternGuardClause != null)
      {
        CheckCondition(patternGuardClause.Condition, consumer);
        return;
      }
    }

foo2.cs

    public void Run(ITreeNode element, ElementProblemAnalyzerData data, IHighlightingConsumer consumer)
    {
      if (element is IIfStatement ifStatement)
      {
        CheckCondition(ifStatement.Condition, consumer);
        return;
      }

      if (element as IWhileStatement whileStatement)
      {
        CheckCondition(whileStatement.Condition, consumer);
        return;
      }

      if (element as IDoStatement doStatement)
      {
        CheckCondition(doStatement.Condition, consumer);
        return;
      }

      if (element as IForStatement forStatement)
      {
        CheckCondition(forStatement.Condition, consumer);
        return;
      }

      if (element as IConditionalTernaryExpression conditionalExpression)
      {
        CheckCondition(conditionalExpression.ConditionOperand, consumer);
        return;
      }

      if (element as IExceptionFilterClause exceptionFilterClause)
      {
        CheckCondition(exceptionFilterClause.Condition, consumer);
        return;
      }

      if (element as IPatternGuardClause patternGuardClause)
      {
        CheckCondition(patternGuardClause.Condition, consumer);
        return;
      }
    }

foo3.cs

    public void Run(ITreeNode element, ElementProblemAnalyzerData data, IHighlightingConsumer consumer)
    {
      switch (element)
      {
        case IIfStatement ifStatement:
          CheckCondition(ifStatement.Condition, consumer);
          break;
        case IWhileStatement whileStatement:
          CheckCondition(whileStatement.Condition, consumer);
          break;
        case IDoStatement doStatement:
          CheckCondition(doStatement.Condition, consumer);
          break;
        case IForStatement forStatement:
          CheckCondition(forStatement.Condition, consumer);
          break;
        case IConditionalTernaryExpression conditionalExpression:
          CheckCondition(conditionalExpression.ConditionOperand, consumer);
          break;
        case IExceptionFilterClause exceptionFilterClause:
          CheckCondition(exceptionFilterClause.Condition, consumer);
          break;
        case IPatternGuardClause patternGuardClause:
          CheckCondition(patternGuardClause.Condition, consumer);
          break;
      }
    }