Rule Definition
The run-time type checking is a time expensive operation and as such should be avoided within loops. In a more general matter, the use of is operator, run-time type checking might indicate a misuse of Object Oriented programming. In deed, it is always recommended to design classes and interfaces so client code do not need to use 'is' operator and down-casting. The recommended way is to prefer polymorphism over 'is' operator and down-casting.

Remediation
Prefer polymorphism over 'is' operator and down-casting. It is always recommended to design classes and interfaces so client code do not need to use 'is' operator and down-casting. The recommended way is to prefer polymorphism over 'is' operator and down-casting.