rust/tests/ui/dropck/issue-28498-ugeh-with-lifetime-param.rs
2024-02-16 20:02:50 +00:00

39 lines
964 B
Rust

//@ run-pass
// Demonstrate the use of the unguarded escape hatch with a lifetime param
// to assert that destructor will not access any dead data.
//
// Compare with ui/span/issue28498-reject-lifetime-param.rs
#![feature(dropck_eyepatch)]
#[derive(Debug)]
struct ScribbleOnDrop(String);
impl Drop for ScribbleOnDrop {
fn drop(&mut self) {
self.0 = format!("DROPPED");
}
}
struct Foo<'a>(u32, &'a ScribbleOnDrop);
unsafe impl<#[may_dangle] 'a> Drop for Foo<'a> {
fn drop(&mut self) {
// Use of `may_dangle` is sound, because destructor never accesses `self.1`.
println!("Dropping Foo({}, _)", self.0);
}
}
fn main() {
let (last_dropped, foo0);
let (foo1, first_dropped);
last_dropped = ScribbleOnDrop(format!("last"));
first_dropped = ScribbleOnDrop(format!("first"));
foo0 = Foo(0, &last_dropped);
foo1 = Foo(1, &first_dropped);
println!("foo0.1: {:?} foo1.1: {:?}", foo0.1, foo1.1);
}