1 files changed, 5 insertions, 12 deletions
diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index 87bfd75bca..c28e31a3da 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -34,7 +34,8 @@ module ActiveRecord
 
     def self.add_reflection(ar, name, reflection)
       ar.clear_reflections_cache
-      ar._reflections = ar._reflections.merge(name.to_s => reflection)
+      name = name.to_s
+      ar._reflections = ar._reflections.except(name).merge!(name => reflection)
     end
 
     def self.add_aggregate_reflection(ar, name, reflection)
@@ -293,7 +294,7 @@ module ActiveRecord
         Relation.create(klass, table, predicate_builder)
       end
 
-      def join_primary_key(_)
+      def join_primary_key(*)
         foreign_key
       end
 
@@ -458,10 +459,6 @@ module ActiveRecord
         options[:primary_key] || primary_key(klass || self.klass)
       end
 
-      def association_primary_key_type
-        klass.type_for_attribute(association_primary_key.to_s)
-      end
-
       def active_record_primary_key
         @active_record_primary_key ||= options[:primary_key] || primary_key(active_record)
       end
@@ -567,7 +564,7 @@ module ActiveRecord
       end
 
       VALID_AUTOMATIC_INVERSE_MACROS = [:has_many, :has_one, :belongs_to]
-      INVALID_AUTOMATIC_INVERSE_OPTIONS = [:conditions, :through, :foreign_key]
+      INVALID_AUTOMATIC_INVERSE_OPTIONS = [:through, :foreign_key]
 
       def add_as_source(seed)
         seed
@@ -722,7 +719,7 @@ module ActiveRecord
         end
       end
 
-      def join_primary_key(klass)
+      def join_primary_key(klass = nil)
         polymorphic? ? association_primary_key(klass) : association_primary_key
       end
 
@@ -859,10 +856,6 @@ module ActiveRecord
         actual_source_reflection.options[:primary_key] || primary_key(klass || self.klass)
       end
 
-      def association_primary_key_type
-        klass.type_for_attribute(association_primary_key.to_s)
-      end
-
       # Gets an array of possible <tt>:through</tt> source reflection names in both singular and plural form.
       #
       #   class Post < ActiveRecord::Base