diff --git a/lib/capybara/rspec/matcher_proxies.rb b/lib/capybara/rspec/matcher_proxies.rb
index 0b5de6d77..16109ff2c 100644
--- a/lib/capybara/rspec/matcher_proxies.rb
+++ b/lib/capybara/rspec/matcher_proxies.rb
@@ -10,9 +10,9 @@ def all(*args, **kwargs, &)
       end
     end
 
-    def within(*args, **kwargs, &)
+    def within(*args, **kwargs, &block)
       if block
-        within_element(*args, **kwargs, &)
+        within_element(*args, **kwargs, &block)
       else
         be_within(*args)
       end