I would like to ask if the that that expression can be used and correct. The only that that expression I can think of is the case where the first that is a pronoun and the second that is a relative pronoun.
For instance: You and your friend Adam are in a car on the road. Your friend Adam told you a while ago that he was seeing a weird car with all people inside dressed up as clowns. And right now, you see the car is passing by.
The car you talked about is that that is going right past us.
Surely, the first that means that car and the second that is a relative pronoun.
I think this is a legitimate expression grammatically, but somehow I also feel it can be wrong as the repetition of the same word that might provoke confusion.