or else the constructor blows up.
This may need to change again with the next release.
# of the possible use cases (even if it
# requires some adaption on the part of
# the author, after all, nothing is free)
- my $source = 'sub {';
+ my $source = "use Carp qw( confess );\n";
+ $source .= 'sub {';
$source .= "\n" . 'my $class = shift;';
$source .= "\n" . 'my $existing = do { no strict "refs"; \${"$class\::singleton"}; };';