in your dreams!

In your dreams! {humorous} -- размечтался; мечтать не вредно; держи карман шире; ага, щас, разбежался;

something that you say to someone who has just told you about something they are hoping for, in order to show that you do not believe it will happen. In your dreams!

Example:'I've a feeling I'll win something on the lottery this week.' 'Dream on!'

see also
[fat chance]
[dream on]
[don't hold your breath]
[держи карман шире]
[ни малейшего шанса]