4 files changed, 26 insertions, 14 deletions
diff --git a/lib/arel/algebra/extensions/class.rb b/lib/arel/algebra/extensions/class.rb
index d005814f91..520111b90f 100644
--- a/lib/arel/algebra/extensions/class.rb
+++ b/lib/arel/algebra/extensions/class.rb
@@ -25,16 +25,6 @@ module Arel
       }
       class_eval methods[method_name], __FILE__, __LINE__
     end
-
-    def hash_on(delegatee)
-      define_method :eql? do |other|
-        self == other
-      end
-
-      define_method :hash do
-        @hash ||= delegatee.hash
-      end
-    end
     
     Class.send(:include, self)
   end
diff --git a/lib/arel/algebra/relations/operations/join.rb b/lib/arel/algebra/relations/operations/join.rb
index e47d9fa9e0..e9320f28e1 100644
--- a/lib/arel/algebra/relations/operations/join.rb
+++ b/lib/arel/algebra/relations/operations/join.rb
@@ -3,12 +3,19 @@ module Arel
     attributes :relation1, :relation2, :predicates
     deriving :==
     delegate :name, :to => :relation1
-    hash_on :relation1
 
     def initialize(relation1, relation2 = Nil.instance, *predicates)
       @relation1, @relation2, @predicates = relation1, relation2, predicates
     end
 
+    def hash
+      @hash ||= :relation1.hash
+    end
+
+    def eql?(other)
+      self == other
+    end
+
     def attributes
       @attributes ||= (relation1.externalize.attributes +
         relation2.externalize.attributes).collect { |a| a.bind(self) }
diff --git a/lib/arel/algebra/relations/utilities/compound.rb b/lib/arel/algebra/relations/utilities/compound.rb
index 676d80a737..5e775618f1 100644
--- a/lib/arel/algebra/relations/utilities/compound.rb
+++ b/lib/arel/algebra/relations/utilities/compound.rb
@@ -1,7 +1,6 @@
 module Arel
   class Compound < Relation
     attr_reader :relation
-    hash_on :relation
     delegate :joins, :join?, :inserts, :taken, :skipped, :name, :externalizable?,
              :column_for, :engine,
              :to => :relation
@@ -14,7 +13,16 @@ module Arel
       OPERATION
     end
 
-    private
+    def hash
+      @hash ||= :relation.hash
+    end
+
+    def eql?(other)
+      self == other
+    end
+
+  private
+
     def arguments_from_block(relation, &block)
       block_given?? [yield(relation)] : []
     end
diff --git a/lib/arel/engines/sql/relations/table.rb b/lib/arel/engines/sql/relations/table.rb
index 0b6574eedc..dd22f44226 100644
--- a/lib/arel/engines/sql/relations/table.rb
+++ b/lib/arel/engines/sql/relations/table.rb
@@ -4,7 +4,6 @@ module Arel
 
     cattr_accessor :engine
     attr_reader :name, :engine
-    hash_on :name
 
     def initialize(name, engine = Table.engine)
       @name, @engine = name.to_s, engine
@@ -16,6 +15,14 @@ module Arel
       end
     end
 
+    def eql?(other)
+      self == other
+    end
+
+    def hash
+      @hash ||= :name.hash
+    end
+
     def format(attribute, value)
       attribute.column.type_cast(value)
     end