diff --git a/lib/cancan/can_definition.rb b/lib/cancan/can_definition.rb
index b81a8bc..dbe56ca 100644
--- a/lib/cancan/can_definition.rb
+++ b/lib/cancan/can_definition.rb
@@ -104,7 +104,7 @@ module CanCan
 
     def nested_subject_matches_conditions?(subject_hash)
       parent, child = subject_hash.shift
-      matches_conditions_hash?(parent, @conditions[parent.class.name.downcase.to_sym])
+      matches_conditions_hash?(parent, @conditions[parent.class.name.downcase.to_sym] || {})
     end
 
     def call_block_with_all(action, subject, extra_args)
diff --git a/spec/cancan/ability_spec.rb b/spec/cancan/ability_spec.rb
index 4dac4d6..160b320 100644
--- a/spec/cancan/ability_spec.rb
+++ b/spec/cancan/ability_spec.rb
@@ -254,6 +254,7 @@ describe CanCan::Ability do
     @ability.can :read, Range, :string => {:length => 3}
     @ability.can?(:read, "foo" => Range).should be_true
     @ability.can?(:read, "foobar" => Range).should be_false
+    @ability.can?(:read, 123 => Range).should be_true
   end
 
   describe "unauthorized message" do