When talking about possibilities in the past, You often use **"could have done".**
>"She could have gone to the theatre with him."<br>
"He couldn't have done such a thing!"<br>
"I could have saved them."<br>
"You could have borrowed the car from him."

I understand **"can have done"** is used in **negative** and **interrogative** statements.
>"She can't have eaten all the food."<br>
"Can he have told them all the secrets?"

But I've not seen an **affirmative** sentence like,
>"She can have gone to the theatre with him."<br>
"He can have told them all the secrets."<br>
"I can have saved them."<br>
"You can have borrowed the car from him."

Why is it? As far as I know, "can" sometimes refers to possibilities as follows.
>"It can be boiling hot in summer."<br>
"She can be nasty."

Did **"can have done"** in affirmatives used to exist before?<br>
Or is it still possible but only used in limited contexts?<br>
If it is, when do you use the structure?<br>
If it's not used at all, what do you think is the reasons?<br><br>
※. I've already read this link: http://ell.stackexchange.com/questions/7519/how-often-do-you-use-cant-have-done-structure