Perl: Wide character in subroutine entry

It took some time for me to trace what dies with the error "Wide character in subroutine entry," and searching for it didn't help much, either.

But in the end, it turned out that Digest::MD5::md5_hex() causes this error if its parameter contains a wide character:

use Digest::MD5 qw(md5_hex);
$x = "El\x{151}d";
md5_hex($x); # Dies with 'Wide character in subroutine entry'

I haven't tested other Digest::MD5 functions, but I hope this helps someone.