| // run-pass |
| #![allow(dead_code)] |
| struct Foo<T: ?Sized> { |
| a: u16, |
| b: T |
| } |
| |
| trait Bar { |
| fn get(&self) -> usize; |
| } |
| |
| impl Bar for usize { |
| fn get(&self) -> usize { *self } |
| } |
| |
| struct Baz<T: ?Sized> { |
| a: T |
| } |
| |
| struct HasDrop<T: ?Sized> { |
| ptr: Box<usize>, |
| data: T |
| } |
| |
| fn main() { |
| // Test that zero-offset works properly |
| let b : Baz<usize> = Baz { a: 7 }; |
| assert_eq!(b.a.get(), 7); |
| let b : &Baz<dyn Bar> = &b; |
| assert_eq!(b.a.get(), 7); |
| |
| // Test that the field is aligned properly |
| let f : Foo<usize> = Foo { a: 0, b: 11 }; |
| assert_eq!(f.b.get(), 11); |
| let ptr1 : *const u8 = &f.b as *const _ as *const u8; |
| |
| let f : &Foo<dyn Bar> = &f; |
| let ptr2 : *const u8 = &f.b as *const _ as *const u8; |
| assert_eq!(f.b.get(), 11); |
| |
| // The pointers should be the same |
| assert_eq!(ptr1, ptr2); |
| |
| // Test that nested DSTs work properly |
| let f : Foo<Foo<usize>> = Foo { a: 0, b: Foo { a: 1, b: 17 }}; |
| assert_eq!(f.b.b.get(), 17); |
| let f : &Foo<Foo<dyn Bar>> = &f; |
| assert_eq!(f.b.b.get(), 17); |
| |
| // Test that get the pointer via destructuring works |
| |
| let f : Foo<usize> = Foo { a: 0, b: 11 }; |
| let f : &Foo<dyn Bar> = &f; |
| let &Foo { a: _, b: ref bar } = f; |
| assert_eq!(bar.get(), 11); |
| |
| // Make sure that drop flags don't screw things up |
| |
| let d : HasDrop<Baz<[i32; 4]>> = HasDrop { |
| ptr: Box::new(0), |
| data: Baz { a: [1,2,3,4] } |
| }; |
| assert_eq!([1,2,3,4], d.data.a); |
| |
| let d : &HasDrop<Baz<[i32]>> = &d; |
| assert_eq!(&[1,2,3,4], &d.data.a); |
| } |