Also destructors are not guaranteed to be run by D specification.
It is perfectly legal to skip such cleanup step upon program
termination.
http://dlang.org/class.html#destructors :
"The garbage collector is not guaranteed to run the destructor
for all unreferenced objects. Furthermore, the order in which the
garbage collector calls destructors for unreference objects is
not specified. This means that when the garbage collector calls a
destructor for an object of a class that has members that are
references to garbage collected objects, those references may no
longer be valid. This means that destructors cannot reference sub
objects. This rule does not apply to auto objects or objects
deleted with the DeleteExpression, as the destructor is not being
run by the garbage collector, meaning all references are valid."
