Remove valid_scope_name? check - use ruby

scope is syntactic sugar for defining a class method. Ruby allows
redefining methods but emits a warning when run with -w. So let's
not implement our own logic for this. Users should run with -w if they
want to be warned about redefined methods.

activerecord/lib/active_record/scoping/named.rb

@@ -172,10 +172,9 @@ module ActiveRecord
         #   Article.featured.titles
 
         def scope(name, scope_options = {})
-          valid_scope_name?(name)
           extension = Module.new(&Proc.new) if block_given?
 
-          singleton_class.send(:redefine_method, name) do |*args|
+          singleton_class.send(:define_method, name) do |*args|
             options = scope_options.respond_to?(:call) ? unscoped { scope_options.call(*args) } : scope_options
             options = scoped.apply_finder_options(options) if options.is_a?(Hash)
 
@@ -184,15 +183,6 @@ module ActiveRecord
             extension ? relation.extending(extension) : relation
           end
         end
-
-      protected
-
-        def valid_scope_name?(name)
-          if respond_to?(name, true)
-            logger.warn "Creating scope :#{name}. " \
-                        "Overwriting existing method #{self.name}.#{name}."
-          end
-        end
       end
     end
   end

activerecord/test/cases/named_scope_test.rb

@@ -393,25 +393,6 @@ class NamedScopeTest < ActiveRecord::TestCase
     end
   end
 
-  def test_scopes_with_reserved_names
-    class << Topic
-      def public_method; end
-      public :public_method
-
-      def protected_method; end
-      protected :protected_method
-
-      def private_method; end
-      private :private_method
-    end
-
-    [:public_method, :protected_method, :private_method].each do |reserved_method|
-      assert Topic.respond_to?(reserved_method, true)
-      ActiveRecord::Base.logger.expects(:warn)
-      Topic.scope(reserved_method)
-    end
-  end
-
   def test_scopes_on_relations
     # Topic.replied
     approved_topics = Topic.scoped.approved.order('id DESC')