Iseq#to_binary: dump flag for **nil (#2508)

RUBY_ISEQ_DUMP_DEBUG=to_binary and the attached test case was failing.
Dump the flag to make sure `**nil` can round-trip properly.

1 files changed, 11 insertions, 0 deletions

diff --git a/test/ruby/test_iseq.rb b/test/ruby/test_iseq.rb
index 2aa6966785..30c4c2815d 100644
--- a/test/ruby/test_iseq.rb
+++ b/test/ruby/test_iseq.rb
@@ -443,6 +443,17 @@ class TestISeq < Test::Unit::TestCase
     end
   end
 
+  def test_to_binary_dumps_nokey
+    iseq = assert_iseq_to_binary(<<-RUBY)
+      o = Object.new
+      class << o
+        def foo(**nil); end
+      end
+      o
+    RUBY
+    assert_equal([[:nokey]], iseq.eval.singleton_method(:foo).parameters)
+  end
+
   def test_to_binary_line_info
     assert_iseq_to_binary("#{<<~"begin;"}\n#{<<~'end;'}", '[Bug #14660]').eval
     begin;