Boolean parameters in methods. Why not?

Question

I'm using reek as an analyzing tool for best practices in my code. However recently I found that if in the method, I have boolean parameters, such as.

def method (flag = true)

reek gives me a warning. Why does reek tell me that it is a warning?

Answer 1

A couple of years before I wrote reek I blogged about this code smell here: http://silkandspinach.net/2004/07/15/avoid-boolean-parameters/

The problems with Boolean parameters all have to do with duplication and the SRP: the called method has two responsibilities, and the caller knows which one it wants to invoke.