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38 lines
1.1 KiB
Rust
38 lines
1.1 KiB
Rust
// 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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// #examples-of-code-that-will-start-to-be-rejected
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// Compare against test/run-pass/issue28498-must-work-ex2.rs
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use std::cell::Cell;
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struct Concrete<'a>(u32, Cell<Option<&'a Concrete<'a>>>);
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struct Foo<T> { data: Vec<T> }
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fn potentially_specialized_wrt_t<T>(t: &T) {
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// Hypothetical code that does one thing for generic T and then is
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// specialized for T == Concrete (and the specialized form can
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// then access a reference held in concrete tuple).
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//
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// (We don't have specialization yet, but we want to allow for it
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// in the future.)
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}
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impl<T> Drop for Foo<T> {
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fn drop(&mut self) {
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potentially_specialized_wrt_t(&self.data[0])
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}
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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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//~^ ERROR borrow may still be in use when destructor runs
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foo.data[1].1.set(Some(&foo.data[0]));
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}
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