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