6 files changed, 26 insertions, 1 deletions
diff --git a/activerecord/test/cases/associations/has_many_through_associations_test.rb b/activerecord/test/cases/associations/has_many_through_associations_test.rb
index af91fb2920..67d18f313a 100644
--- a/activerecord/test/cases/associations/has_many_through_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_through_associations_test.rb
@@ -894,4 +894,11 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
     end
   end
 
+  test "has many through with default scope on the target" do
+    person = people(:michael)
+    assert_equal [posts(:thinking)], person.first_posts
+
+    readers(:michael_authorless).update(first_post_id: 1)
+    assert_equal [posts(:thinking)], person.reload.first_posts
+  end
 end
diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
index 64f1c9f6cc..379c0c0758 100644
--- a/activerecord/test/cases/relations_test.rb
+++ b/activerecord/test/cases/relations_test.rb
@@ -1488,4 +1488,17 @@ class RelationTest < ActiveRecord::TestCase
       Array.send(:remove_method, :__omg__)
     end
   end
+
+  test "merge collapses wheres from the LHS only" do
+    left  = Post.where(title: "omg").where(comments_count: 1)
+    right = Post.where(title: "wtf").where(title: "bbq")
+
+    expected = [left.where_values[1]] + right.where_values
+    merged   = left.merge(right)
+
+    assert_equal expected, merged.where_values
+    assert !merged.to_sql.include?("omg")
+    assert merged.to_sql.include?("wtf")
+    assert merged.to_sql.include?("bbq")
+  end
 end
diff --git a/activerecord/test/fixtures/readers.yml b/activerecord/test/fixtures/readers.yml
index 8a6076655b..14b883f041 100644
--- a/activerecord/test/fixtures/readers.yml
+++ b/activerecord/test/fixtures/readers.yml
@@ -2,8 +2,10 @@ michael_welcome:
   id: 1
   post_id: 1
   person_id: 1
+  first_post_id: 2
 
 michael_authorless:
   id: 2
   post_id: 3
-  person_id: 1
-\ No newline at end of file
+  person_id: 1
+  first_post_id: 3
diff --git a/activerecord/test/models/person.rb b/activerecord/test/models/person.rb
index c602ca5eac..fa717ef8d6 100644
--- a/activerecord/test/models/person.rb
+++ b/activerecord/test/models/person.rb
@@ -15,6 +15,7 @@ class Person < ActiveRecord::Base
   has_many :fixed_bad_references, -> { where :favourite => true }, :class_name => 'BadReference'
   has_one  :favourite_reference, -> { where 'favourite=?', true }, :class_name => 'Reference'
   has_many :posts_with_comments_sorted_by_comment_id, -> { includes(:comments).order('comments.id') }, :through => :readers, :source => :post
+  has_many :first_posts, -> { where(id: [1, 2]) }, through: :readers
 
   has_many :jobs, :through => :references
   has_many :jobs_with_dependent_destroy,    :source => :job, :through => :references, :dependent => :destroy
diff --git a/activerecord/test/models/reader.rb b/activerecord/test/models/reader.rb
index f8fb9c573e..3a6b7fad34 100644
--- a/activerecord/test/models/reader.rb
+++ b/activerecord/test/models/reader.rb
@@ -2,6 +2,7 @@ class Reader < ActiveRecord::Base
   belongs_to :post
   belongs_to :person, :inverse_of => :readers
   belongs_to :single_person, :class_name => 'Person', :foreign_key => :person_id, :inverse_of => :reader
+  belongs_to :first_post, -> { where(id: [2, 3]) }
 end
 
 class SecureReader < ActiveRecord::Base
diff --git a/activerecord/test/schema/schema.rb b/activerecord/test/schema/schema.rb
index 46219c53db..cd9835259a 100644
--- a/activerecord/test/schema/schema.rb
+++ b/activerecord/test/schema/schema.rb
@@ -567,6 +567,7 @@ ActiveRecord::Schema.define do
     t.integer :post_id, :null => false
     t.integer :person_id, :null => false
     t.boolean :skimmer, :default => false
+    t.integer :first_post_id
   end
 
   create_table :references, :force => true do |t|