Bitwise operations on wide characters have been deprecated since 5.24, and issue a warning. This has been changed to be fatal in blead. However, the change that is currently in place will die in places that previously didn't get the deprecation warning at all. If one of the strings in a bitwise operation is shorter than where the wide characters exist in the other, no warning would be issued. The resulting string would either stop at the length of the shorter string for &, or have the remaining characters copied unmodified from the longer string for ^ and |. For example: perl -we' my $f = "" & "\x{ABCD}" ' This will not warn on 5.26, but is fatal in blead. The change was introduced in 08b6664b858b8fd4b5c0c27542763337b6d78e46. This breaks code that I'm using, including newer versions of JSON::PP. The reason I'm using this is admittedly an abuse of the bitwise ops for number detection. The result of ($var ^ "") can tell you the status of the internal flags for a if value is a valid number, which is needed for serialization. The alternative is using B to examine the flags, which is significantly slower. Doing operations like this doesn't run into the problems motivating the removal of bitwise ops on wide characters, so I would vote for restoring support for it. If that is not an option, there at least needs to be a release cycle with a deprecation warning for this.Thread Next