repro.rb

require 'bundler/inline'

gemfile(true) do
  source 'https://rubygems.org'
  gem 'activerecord', '4.2.4'
  gem 'sqlite3'
end

require 'active_record'
require 'minitest/autorun'
require 'logger'

ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: ':memory:')
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table(:things) do |t|
    t.boolean :hidden
  end
end

class Thing < ActiveRecord::Base
  scope :hidden, -> { where(hidden: true) }
end


class ReproTest < Minitest::Test
  def test_generates_correct_where_sql
    sql = Thing.hidden.arel.where_sql
    puts sql
    assert sql == "WHERE \"things\".\"hidden\" = 't'"
  end
end

# 4.2.2: WHERE "things"."hidden" = 't'
# 4.2.3: WHERE "things"."hidden" = ?
# 4.2.4: WHERE "things"."hidden" = ?