32 lines
640 B
Rust
32 lines
640 B
Rust
// run-pass
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#![allow(dead_code)]
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use std::mem::ManuallyDrop;
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union MaybeItem<T: Iterator> {
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elem: ManuallyDrop<T::Item>,
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none: (),
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}
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union U<A, B> where A: Copy, B: Copy {
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a: A,
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b: B,
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}
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unsafe fn union_transmute<A, B>(a: A) -> B where A: Copy, B: Copy {
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U { a }.b
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}
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fn main() {
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unsafe {
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let b = union_transmute::<(u8, u8), u16>((1, 1));
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assert_eq!(b, (1 << 8) + 1);
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let v: Vec<u8> = vec![1, 2, 3];
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let mut i = v.iter();
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i.next();
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let mi = MaybeItem::<std::slice::Iter<_>> { elem: ManuallyDrop::new(i.next().unwrap()) };
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assert_eq!(**mi.elem, 2);
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}
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}
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