1 files changed, 11 insertions, 0 deletions
diff --git a/test/ruby/test_optimization.rb b/test/ruby/test_optimization.rb
index 8d669e502c..70b6bde6ed 100644
--- a/test/ruby/test_optimization.rb
+++ b/test/ruby/test_optimization.rb
@@ -451,6 +451,17 @@ class TestRubyOptimization < Test::Unit::TestCase
     assert_equal(3, one_plus_two)
   end
 
+  def test_tailcall_and_post_arg
+    tailcall(<<~RUBY)
+      def ret_const = :ok
+
+      def post_arg(_a = 1, _b) = ret_const
+    RUBY
+
+    # YJIT probably uses a fallback on the call to post_arg
+    assert_equal(:ok, post_arg(0))
+  end
+
   def test_tailcall_interrupted_by_sigint
     bug12576 = 'ruby-core:76327'
     script = "#{<<-"begin;"}\n#{<<~'end;'}"