2 files changed, 18 insertions, 1 deletions
diff --git a/activerecord/lib/active_record/table_metadata.rb b/activerecord/lib/active_record/table_metadata.rb
index b618e5cfcd..71efc1829a 100644
--- a/activerecord/lib/active_record/table_metadata.rb
+++ b/activerecord/lib/active_record/table_metadata.rb
@@ -44,7 +44,7 @@ module ActiveRecord
     end
 
     def associated_table(table_name)
-      association = klass._reflect_on_association(table_name) || klass._reflect_on_association(table_name.singularize)
+      association = klass._reflect_on_association(table_name) || klass._reflect_on_association(table_name.to_s.singularize)
 
       if !association && table_name == arel_table.name
         return self
diff --git a/activerecord/test/cases/associations/has_one_associations_test.rb b/activerecord/test/cases/associations/has_one_associations_test.rb
index ed22a9802f..aa910ba409 100644
--- a/activerecord/test/cases/associations/has_one_associations_test.rb
+++ b/activerecord/test/cases/associations/has_one_associations_test.rb
@@ -648,6 +648,7 @@ class HasOneAssociationsTest < ActiveRecord::TestCase
   class SpecialBook < ActiveRecord::Base
     self.table_name = "books"
     belongs_to :author, class_name: "SpecialAuthor"
+    has_one :subscription, class_name: "SpecialSupscription", foreign_key: "subscriber_id"
   end
 
   class SpecialAuthor < ActiveRecord::Base
@@ -655,6 +656,11 @@ class HasOneAssociationsTest < ActiveRecord::TestCase
     has_one :book, class_name: "SpecialBook", foreign_key: "author_id"
   end
 
+  class SpecialSupscription < ActiveRecord::Base
+    self.table_name = "subscriptions"
+    belongs_to :book, class_name: "SpecialBook"
+  end
+
   def test_assocation_enum_works_properly
     author = SpecialAuthor.create!(name: "Test")
     book = SpecialBook.create!(status: "published")
@@ -662,4 +668,15 @@ class HasOneAssociationsTest < ActiveRecord::TestCase
 
     refute_equal 0, SpecialAuthor.joins(:book).where(books: { status: "published" }).count
   end
+
+  def test_assocation_enum_works_properly_with_nested_join
+    author = SpecialAuthor.create!(name: "Test")
+    book = SpecialBook.create!(status: "published")
+    author.book = book
+
+    where_clause = { books: { subscriptions: { subscriber_id: nil } } }
+    assert_nothing_raised do
+      SpecialAuthor.joins(book: :subscription).where.not(where_clause)
+    end
+  end
 end