2 files changed, 12 insertions, 0 deletions
diff --git a/actionpack/lib/action_dispatch/routing/route_set.rb b/actionpack/lib/action_dispatch/routing/route_set.rb
index 342b6ec23d..3ae9f92c0b 100644
--- a/actionpack/lib/action_dispatch/routing/route_set.rb
+++ b/actionpack/lib/action_dispatch/routing/route_set.rb
@@ -218,6 +218,7 @@ module ActionDispatch
                 keys -= t.url_options.keys if t.respond_to?(:url_options)
                 keys -= options.keys
               end
+              keys -= inner_options.keys
               result.merge!(Hash[keys.zip(args)])
             end
 
diff --git a/actionpack/test/dispatch/routing/route_set_test.rb b/actionpack/test/dispatch/routing/route_set_test.rb
index d57b1a5637..0e488d2b88 100644
--- a/actionpack/test/dispatch/routing/route_set_test.rb
+++ b/actionpack/test/dispatch/routing/route_set_test.rb
@@ -69,6 +69,17 @@ module ActionDispatch
         end
       end
 
+      test "explicit keys win over implicit keys" do
+        draw do
+          resources :foo do
+            resources :bar, to: SimpleApp.new('foo#show')
+          end
+        end
+
+        assert_equal '/foo/1/bar/2', url_helpers.foo_bar_path(1, 2)
+        assert_equal '/foo/1/bar/2', url_helpers.foo_bar_path(2, foo_id: 1)
+      end
+
       private
         def clear!
           @set.clear!