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// Example taken from RFC 1238 text
// https://github.com/rust-lang/rfcs/blob/master/text/1238-nonparametric-dropck.md
// #examples-of-code-that-will-start-to-be-rejected
// Compare against test/run-pass/issue28498-must-work-ex2.rs
use std::cell::Cell;
struct Concrete<'a>(u32, Cell<Option<&'a Concrete<'a>>>);
struct Foo<T> { data: Vec<T> }
fn potentially_specialized_wrt_t<T>(t: &T) {
// Hypothetical code that does one thing for generic T and then is
// specialized for T == Concrete (and the specialized form can
// then access a reference held in concrete tuple).
//
// (We don't have specialization yet, but we want to allow for it
// in the future.)
}
impl<T> Drop for Foo<T> {
fn drop(&mut self) {
potentially_specialized_wrt_t(&self.data[0])
}
}
fn main() {
let mut foo = Foo { data: Vec::new() };
foo.data.push(Concrete(0, Cell::new(None)));
foo.data.push(Concrete(0, Cell::new(None)));
foo.data[0].1.set(Some(&foo.data[1]));
//~^ ERROR borrow may still be in use when destructor runs
foo.data[1].1.set(Some(&foo.data[0]));
}
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