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1 // Issue 36278: On an unsized struct with >1 level of nontrivial
2 // nesting, ensure we are computing dynamic size of prefix correctly.
3 
4 use std::mem;
5 
6 const SZ: usize = 100;
7 struct P<T: ?Sized>([u8; SZ], T);
8 
9 type Ack<T> = P<P<T>>;
10 
main()11 fn main() {
12     let size_of_sized;
13     let size_of_unsized;
14     let x: Box<Ack<[u8; 0]>> = Box::new(P([0; SZ], P([0; SZ], [0; 0])));
15     size_of_sized = mem::size_of_val::<Ack<_>>(&x);
16     let align_of_sized = mem::align_of_val::<Ack<_>>(&x);
17     let y: Box<Ack<[u8]>> = x;
18     size_of_unsized = mem::size_of_val::<Ack<_>>(&y);
19     assert_eq!(size_of_sized, size_of_unsized);
20     assert_eq!(align_of_sized, 1);
21     assert_eq!(mem::align_of_val::<Ack<_>>(&y), 1);
22 }
23