$ gcc -E - | wc
#define EXP(X) X X X X X X X X X X X X X X X X
#define LOL1 EXP(LOL)
#define LOL2 EXP(LOL1)
#define LOL3 EXP(LOL2)
#define LOL4 EXP(LOL3)
#define LOL5 EXP(LOL4)
11 1048588 4194376
EDIT: In spite of those who are downvoting my comment without even replying, I'm leaving it anyway; cause sharing good software outweighs whatever loss they intend to inflict.
"Btw I use Rust".
I don't get your analogy.
How do you know someone uses "X"? Don't worry, they'll tell you.
The desk sergeant asks, "Can you describe the mugger?"
"Not really, he grabbed me from behind. I know he's a man, bigger than me, and he's vegan."
"How on earth do you know he's vegan?"
"He bloody told me!"