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Commit | Line | Data |
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b7449926 | 1 | // run-pass |
1a4d82fc | 2 | use std::mem::size_of; |
0531ce1d XL |
3 | use std::num::NonZeroUsize; |
4 | use std::ptr::NonNull; | |
1a4d82fc JJ |
5 | use std::rc::Rc; |
6 | use std::sync::Arc; | |
7 | ||
85aaf69f | 8 | trait Trait { fn dummy(&self) { } } |
e9174d1e SL |
9 | trait Mirror { type Image; } |
10 | impl<T> Mirror for T { type Image = T; } | |
11 | struct ParamTypeStruct<T>(T); | |
12 | struct AssocTypeStruct<T>(<T as Mirror>::Image); | |
1a4d82fc JJ |
13 | |
14 | fn main() { | |
15 | // Functions | |
c34b1796 AL |
16 | assert_eq!(size_of::<fn(isize)>(), size_of::<Option<fn(isize)>>()); |
17 | assert_eq!(size_of::<extern "C" fn(isize)>(), size_of::<Option<extern "C" fn(isize)>>()); | |
1a4d82fc JJ |
18 | |
19 | // Slices - &str / &[T] / &mut [T] | |
20 | assert_eq!(size_of::<&str>(), size_of::<Option<&str>>()); | |
c34b1796 AL |
21 | assert_eq!(size_of::<&[isize]>(), size_of::<Option<&[isize]>>()); |
22 | assert_eq!(size_of::<&mut [isize]>(), size_of::<Option<&mut [isize]>>()); | |
1a4d82fc JJ |
23 | |
24 | // Traits - Box<Trait> / &Trait / &mut Trait | |
25 | assert_eq!(size_of::<Box<Trait>>(), size_of::<Option<Box<Trait>>>()); | |
26 | assert_eq!(size_of::<&Trait>(), size_of::<Option<&Trait>>()); | |
27 | assert_eq!(size_of::<&mut Trait>(), size_of::<Option<&mut Trait>>()); | |
28 | ||
29 | // Pointers - Box<T> | |
c34b1796 | 30 | assert_eq!(size_of::<Box<isize>>(), size_of::<Option<Box<isize>>>()); |
1a4d82fc JJ |
31 | |
32 | // The optimization can't apply to raw pointers | |
c34b1796 AL |
33 | assert!(size_of::<Option<*const isize>>() != size_of::<*const isize>()); |
34 | assert!(Some(0 as *const isize).is_some()); // Can't collapse None to null | |
1a4d82fc JJ |
35 | |
36 | struct Foo { | |
c34b1796 | 37 | _a: Box<isize> |
1a4d82fc | 38 | } |
c34b1796 | 39 | struct Bar(Box<isize>); |
1a4d82fc JJ |
40 | |
41 | // Should apply through structs | |
42 | assert_eq!(size_of::<Foo>(), size_of::<Option<Foo>>()); | |
43 | assert_eq!(size_of::<Bar>(), size_of::<Option<Bar>>()); | |
44 | // and tuples | |
c34b1796 | 45 | assert_eq!(size_of::<(u8, Box<isize>)>(), size_of::<Option<(u8, Box<isize>)>>()); |
1a4d82fc | 46 | // and fixed-size arrays |
c34b1796 | 47 | assert_eq!(size_of::<[Box<isize>; 1]>(), size_of::<Option<[Box<isize>; 1]>>()); |
1a4d82fc JJ |
48 | |
49 | // Should apply to NonZero | |
0531ce1d XL |
50 | assert_eq!(size_of::<NonZeroUsize>(), size_of::<Option<NonZeroUsize>>()); |
51 | assert_eq!(size_of::<NonNull<i8>>(), size_of::<Option<NonNull<i8>>>()); | |
1a4d82fc JJ |
52 | |
53 | // Should apply to types that use NonZero internally | |
c34b1796 AL |
54 | assert_eq!(size_of::<Vec<isize>>(), size_of::<Option<Vec<isize>>>()); |
55 | assert_eq!(size_of::<Arc<isize>>(), size_of::<Option<Arc<isize>>>()); | |
56 | assert_eq!(size_of::<Rc<isize>>(), size_of::<Option<Rc<isize>>>()); | |
1a4d82fc JJ |
57 | |
58 | // Should apply to types that have NonZero transitively | |
59 | assert_eq!(size_of::<String>(), size_of::<Option<String>>()); | |
60 | ||
e9174d1e SL |
61 | // Should apply to types where the pointer is substituted |
62 | assert_eq!(size_of::<&u8>(), size_of::<Option<ParamTypeStruct<&u8>>>()); | |
63 | assert_eq!(size_of::<&u8>(), size_of::<Option<AssocTypeStruct<&u8>>>()); | |
1a4d82fc | 64 | } |