class NG
	attr_reader :var
	def main
		@var=0
		p var #=> 0
		eval 'p var' #=> nil (NG)
		var=0 #<- bug trigger
	end
end

class OK
	attr_reader :var
	def main
		@var=0
		p var #=> 0
		eval 'p var' #=> 0 (OK)
	end
end

NG.new.main
OK.new.main