#![feature(dropck_eyepatch)] // This is a support file for ../dropck-eyepatch-extern-crate.rs // // The point of this test is to illustrate that the `#[may_dangle]` // attribute specifically allows, in the context of a type // implementing `Drop`, a generic parameter to be instantiated with a // lifetime that does not strictly outlive the owning type itself, // and that this attribute's effects are preserved when importing // the type from another crate. // // See also ../dropck-eyepatch.rs for more information about the general // structure of the test. use std::fmt; pub struct Dt(pub &'static str, pub A); pub struct Dr<'a, B:'a+fmt::Debug>(pub &'static str, pub &'a B); pub struct Pt(pub &'static str, pub A, pub B); pub struct Pr<'a, 'b, B:'a+'b+fmt::Debug>(pub &'static str, pub &'a B, pub &'b B); pub struct St(pub &'static str, pub A); pub struct Sr<'a, B:'a+fmt::Debug>(pub &'static str, pub &'a B); impl Drop for Dt { fn drop(&mut self) { println!("drop {} {:?}", self.0, self.1); } } impl<'a, B: fmt::Debug> Drop for Dr<'a, B> { fn drop(&mut self) { println!("drop {} {:?}", self.0, self.1); } } unsafe impl<#[may_dangle] A, B: fmt::Debug> Drop for Pt { // (unsafe to access self.1 due to #[may_dangle] on A) fn drop(&mut self) { println!("drop {} {:?}", self.0, self.2); } } unsafe impl<#[may_dangle] 'a, 'b, B: fmt::Debug> Drop for Pr<'a, 'b, B> { // (unsafe to access self.1 due to #[may_dangle] on 'a) fn drop(&mut self) { println!("drop {} {:?}", self.0, self.2); } }