class Base @@stuff =  of Base.class def self.stuff @@stuff end end class T < Base end class A < Base @@stuff = [A, T] end def dance(t : Base.class) pp t.stuff end dance(A)
This errors with:
Error: class variable '@@stuff' of A is already defined as Array(Base.class) in Base if you remove one of the elements from
A@@stuff, but works fine with 2 or more. Why?