1 files changed, 8 insertions, 11 deletions
diff --git a/activerecord/lib/active_record/associations/builder/has_one.rb b/activerecord/lib/active_record/associations/builder/has_one.rb
index bc8a212bee..cdb45e8e58 100644
--- a/activerecord/lib/active_record/associations/builder/has_one.rb
+++ b/activerecord/lib/active_record/associations/builder/has_one.rb
@@ -2,12 +2,15 @@ require 'active_support/core_ext/object/inclusion'
 
 module ActiveRecord::Associations::Builder
   class HasOne < SingularAssociation #:nodoc:
-    self.macro = :has_one
-
-    self.valid_options += [:order, :as]
+    def macro
+      :has_one
+    end
 
-    class_attribute :through_options
-    self.through_options = [:through, :source, :source_type]
+    def valid_options
+      valid = super + [:order, :as]
+      valid += [:through, :source, :source_type] if options[:through]
+      valid
+    end
 
     def constructable?
       !options[:through]
@@ -21,12 +24,6 @@ module ActiveRecord::Associations::Builder
 
     private
 
-      def validate_options
-        valid_options = self.class.valid_options
-        valid_options += self.class.through_options if options[:through]
-        options.assert_valid_keys(valid_options)
-      end
-
       def configure_dependency
         if options[:dependent]
           unless options[:dependent].in?([:destroy, :delete, :nullify, :restrict])