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28 lines
695 B
Rust
28 lines
695 B
Rust
//@ run-pass
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// Example taken from RFC 1238 text
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// https://github.com/rust-lang/rfcs/blob/master/text/1238-nonparametric-dropck.md
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// #example-of-the-unguarded-escape-hatch
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#![feature(dropck_eyepatch)]
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use std::cell::Cell;
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struct Concrete<'a>(#[allow(dead_code)] u32, Cell<Option<&'a Concrete<'a>>>);
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struct Foo<T> { data: Vec<T> }
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// Below is the UGEH attribute
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unsafe impl<#[may_dangle] T> Drop for Foo<T> {
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fn drop(&mut self) { }
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}
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fn main() {
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let mut foo = Foo { data: Vec::new() };
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foo.data.push(Concrete(0, Cell::new(None)));
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foo.data.push(Concrete(0, Cell::new(None)));
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foo.data[0].1.set(Some(&foo.data[1]));
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foo.data[1].1.set(Some(&foo.data[0]));
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}
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