Why does it *not* work with the last example?

named_captures.rb

HHVM_VERSION_REGEXP = /
  (?:hhvm$)
  |(
    hhvm-(
      (?<numeric>\d+(\.\d+)*)(?<lts>-lts)?$
      |
      (?<version>
        dbg$|
        dev$|
        nightly$|
        nightly-dbg$|
        dev-nightly$
      )
  )
  /x

vers = %w(
  hhvm
  hhvm-nightly
  hhvm-
  hhvm-3.25
  hhvm-3.25-lts
)
    
vers.each do |v|
  if md = HHVM_VERSION_REGEXP.match(v)
    puts md.inspect
  end
end