Rule Definition
By explicitly rethrowing the exception, the stack trace is modified so that the rethrowing line appears to be the source. This is almost always certainly a bad idea, as vital information is lost. So be careful how you rethrow exceptions.

Remediation
Use a nested exception in case there is a need to re-throw the exception.

Violation Code Sample

catch (HibernateException ex)
{
 if (transaction != null) { transaction.Rollback(); }
 throw ex;
}

Fixed Code Sample

catch (HibernateException ex)
{
 if (transaction != null) { transaction.Rollback(); }
 throw new Exception("Email already in use", ex);
}
______________________________________________

catch (HibernateException ex)
{
 if (transaction != null) { transaction.Rollback(); }
 throw;
}

https://www.openmymind.net/FoundationsOfProgramming.pdf p-68