class Reek::SmellDetectors::SubclassedFromCoreClass

Subclassing core classes in Ruby can lead to unexpected side effects. Knowing that Ruby has a core library, which is written in C, and a standard library, which is written in Ruby, if you do not know exactly how these core classes operate at the C level, you are gonna have a bad time.

Source: words.steveklabnik.com/beware-subclassing-ruby-core-classes