39 lines
718 B
Rust
39 lines
718 B
Rust
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use std::cell::Cell;
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use std::ops::Deref;
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use std::mem::ManuallyDrop;
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union Wrap<T> { x: ManuallyDrop<T> }
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impl<T> Drop for Wrap<T> {
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fn drop(&mut self) {
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unsafe { std::ptr::drop_in_place(&mut *self.x as *mut T); }
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}
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}
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impl<T> Wrap<T> {
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fn new(x: T) -> Self {
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Wrap { x: ManuallyDrop::new(x) }
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}
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}
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impl<T> Deref for Wrap<T> {
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type Target = T;
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#[inline]
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fn deref(&self) -> &Self::Target {
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unsafe {
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&self.x
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}
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}
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}
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struct C<'a>(Cell<Option<&'a C<'a>>>);
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impl<'a> Drop for C<'a> {
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fn drop(&mut self) {}
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}
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fn main() {
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let v : Wrap<C> = Wrap::new(C(Cell::new(None)));
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v.0.set(Some(&v)); //~ ERROR: `v` does not live long enough
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}
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