Does it mean the same as "Don't say"?

Native speaker’s answer
Rebecca
No, "you don't say" is quite different from "don't say!" "Don't say" indicates to not say something, whereas "you don't say" is another way of saying "no way" or "really?" It's used to express amazement or disbelief. Although, it's often used sarcastically or ironically, too. Even here, Gwyneth doesn't look surprised at all, which makes the "you don't say" seem very ironic. Ex: Don't say that! It's rude. Ex: A: It's hot outside. B: You don't say! I thought it was the middle of winter.