Perl 5.12 doesn't like the following alias syntax:
use Data::Alias;
alias { ($x, $y) = ($y, $x) };
I get the following error:
Not enough arguments for Data::Alias::alias at da.pl line 2, near ""
syntax error at da.pl line 2, near ""
da.pl had compilation errors.
Perl 5.10 is ok with it and runs normally.