sub meta::eval_in {
  my ($what, $where) = @_;
  # Obtain next eval-number and alias it to the designated location
  @locations{eval('__FILE__') =~ /\(eval (\d+)\)/} = ($where);  # <- step 1
  my $result = eval $what;                                      # <- step 2
  $@ =~ s/\(eval \d+\)/$where/ if $@;
  warn $@ if $@;
  $result;
}