static void Main(string[] args)
{
using (var db = new DbManager())
{
db.SetSpCommand(""); // ok
db.SetInsertCommand(""); // ok
db.SetUpdateCommand(""); // ok
db.Prepare(); // ok
db.ExecuteNonQuery(); // ok
db.SetCommand(""); // ERROR:
// error CS0584: Internal compiler error: Object reference not set to an instance of an object
// error CS0201: Only assignment, call, increment, decrement, and new object expressions can be used as a statement
}
}