Issue #16294 has been updated by Eregon (Benoit Daloze). nobu (Nobuyoshi Nakada) wrote in #note-8:

At the latest dev-meeting, there was a suggestion that whereas `MatchData` cannot be dumped, `Regexp.allocate` might be used by serializer libraries.

That does not seem used in practice. TruffleRuby already does not define `Regexp.allocate`, and there seems to be no compatibility issue with that except some specs. `Regexp.new` (or `eval`) is good enough for deserializing regexps. ---------------------------------------- Feature #16294: Make MatchData frozen and forbid MatchData.allocate https://bugs.ruby-lang.org/issues/16294#change-104928 * Author: Eregon (Benoit Daloze) * Status: Closed * Priority: Normal ---------------------------------------- Currently, `MatchData.allocate` is allowed, but almost every MatchData method called on it `raise TypeError, 'uninitialized Match'`. I think MatchData should be frozen, none of its internal fields are mutable and I don't see any use case for storing instance variables on it. Once frozen, we can implement MatchData#dup and #clone as just `return self`, and we don't need to check for the uninitialized case. And Marshal can have special treatment to create an initialized MatchData directly. My main motivation is looking at the code in TruffleRuby required to implement `MatchData.allocate` and check if it's initialized in so many places: https://github.com/oracle/truffleruby/pull/1792/files Thoughts? Anyone against? cc @alanwu -- https://bugs.ruby-lang.org/