We aren't dumping compare_by_identity Hash instances correctly:
$ cx ruby-master ruby -e 's = Hash.new; p Marshal.dump(s)'
"\x04\b{\x00"
$ cx ruby-master ruby -e 's = Hash.new; s.compare_by_identity; p Marshal.dump(s)'
"\x04\bC:\tHash{\x00"
$ jruby -e 's = Hash.new; p Marshal.dump(s)'
"\x04\b{\x00"
$ jruby -e 's = Hash.new; s.compare_by_identity; p Marshal.dump(s)'
"\x04\b{\x00"
How embarrassing.
We aren't dumping
compare_by_identityHash instances correctly:How embarrassing.