diff --git a/lib/capybara/selector/selector.rb b/lib/capybara/selector/selector.rb
index 55e84c4ca6..62452c8018 100644
--- a/lib/capybara/selector/selector.rb
+++ b/lib/capybara/selector/selector.rb
@@ -214,6 +214,7 @@ def initialize(definition, config:, format:)
     def format
       @format || @definition.default_format
     end
+    alias_method :current_format, :format
 
     def enable_aria_label
       @config[:enable_aria_label]
@@ -239,7 +240,7 @@ def add_error(error_msg)
       errors << error_msg
     end
 
-    def expression_for(name, locator, config: @config, format: format, **options)
+    def expression_for(name, locator, config: @config, format: current_format, **options)
       Selector.new(name, config: config, format: format).call(locator, **options)
     end
 
diff --git a/spec/selector_spec.rb b/spec/selector_spec.rb
index 52f27f35a3..fb09e503ff 100644
--- a/spec/selector_spec.rb
+++ b/spec/selector_spec.rb
@@ -164,7 +164,7 @@
 
     describe 'xpath' do
       it 'uses filter names passed in' do
-        selector = Capybara.add_selector :test do
+        Capybara.add_selector :test do
           xpath(:something, :other) { |_locator| XPath.descendant }
         end
         selector = Capybara::Selector.new :test, config: nil, format: nil