Not all finalized objects are untracked

[beta-ziliani]

Likely this is expected behavior, but it should be documented then: not every freed object's memory is reclaimed, meaning that the untracking of objects does not match the finalizing of objects:

class Z
  @@deleted = Array(Int32).new(1000, 0)

  def initialize(@i : Int32)
  end

  def finalize
    @@deleted[@i] = 1
  end

  def self.deleted
    @@deleted.sum
  end
end

(0..1000).each { |i| Z.new i }
GC.collect
puts "Deleted: #{Z.deleted}" #=> 999
PerfTools::MemProf.log_object_counts(STDOUT) #=> ...\n 488	Z

In reality those 488 Z's are not live.