package SomeClass;
#...
sub new {
  # ...
  eval { die("Oops!"); };
  if($@) {
    die("Something has gone wrong: $@");
  }
  # ...
}
#...
package main;
#...
my $obj = eval { $obj->new };
unless(defined($obj)) {
  die("Can't SomeClass->new(): $@");
}
#...