Well I think there is something wrong with DataMapper::Collection slice, when mixing queries and slices. Any thoughts? I'm working on what seems to be an issue

Gemfile

# A sample Gemfile
source "https://rubygems.org"

gem 'data_mapper'
gem 'dm-sqlite-adapter'

test.rb

require 'bundler'
Bundler.require

DataMapper.setup :default, 'sqlite:///tmp/project.db'

class Person
  include DataMapper::Resource

  property :id, Serial
  property :age, String
end

DataMapper.auto_migrate!

Person.create age: 1
Person.create age: 2
Person.create age: 3
Person.create age: 4
Person.create age: 5
Person.create age: 6

Person[0..3] # this should include Person instances with age 1, 2 and 3
person = Person[0..3] #his should also include the same people

Person[0..3].all :age.gt => 2 # This must return the person with age 3
# => [#<Person @id=3 @age="3">, #<Person @id=4 @age="4">, #<Person @id=5 @age="5">, #<Person @id=6 @age="6">]
person.all :age.gt => 2 # Well check out what returns
# => [#<Person @id=3 @age="3">, #<Person @id=4 @age="4">]
# Any thoughts on that?

# But the problem goes even further

Person[0..3][1..1].all :age.gt => 2
# => [#<Person @id=4 @age="4">]
person[1..1].all :age.gt => 2
# => []