This issue is tracking for gem release of StringScanner class.
#5 [ruby-core:84345] Updated by hsbt (Hiroshi SHIBATA) 4 months ago
I updated gemspec at r61333.
But I couldn't ship strscan gem to rubygems.org:
If above pull request is not handled until Ruby 2.5 release, I will release strscan-1.0.0 in next year.