diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index e4fd63cf0e..3bc578b379 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -66,8 +66,8 @@ class Mapping #:nodoc:
         attr_reader :scope, :options, :requirements, :conditions, :defaults
         attr_reader :to, :default_controller, :default_action
 
-        def initialize(set, scope, path, options)
-          @set, @scope = set, scope
+        def initialize(scope, path, options)
+          @scope = scope
           @requirements, @conditions, @defaults = {}, {}, {}
 
           options = scope[:options].merge(options) if scope[:options]
@@ -1515,7 +1515,7 @@ def add_route(action, options) # :nodoc:
             options[:as] = name_for_action(options[:as], action)
           end
 
-          mapping = Mapping.new(@set, @scope, URI.parser.escape(path), options)
+          mapping = Mapping.new(@scope, URI.parser.escape(path), options)
           app, conditions, requirements, defaults, as, anchor = mapping.to_route
           @set.add_route(app, conditions, requirements, defaults, as, anchor)
         end
diff --git a/actionpack/test/dispatch/mapper_test.rb b/actionpack/test/dispatch/mapper_test.rb
index e3dcf9b88a..bf82e09f39 100644
--- a/actionpack/test/dispatch/mapper_test.rb
+++ b/actionpack/test/dispatch/mapper_test.rb
@@ -38,7 +38,7 @@ def test_initialize
 
       def test_mapping_requirements
         options = { :controller => 'foo', :action => 'bar', :via => :get }
-        m = Mapper::Mapping.new FakeSet.new, {}, '/store/:name(*rest)', options
+        m = Mapper::Mapping.new({}, '/store/:name(*rest)', options)
         _, _, requirements, _ = m.to_route
         assert_equal(/.+?/, requirements[:rest])
       end