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// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![feature(dropck_eyepatch, rustc_attrs)]
// The point of this test is to test uses of `#[may_dangle]` attribute
// where the formal declaration order (in the impl generics) does not
// match the actual usage order (in the type instantiation).
//
// See also dropck-eyepatch.rs for more information about the general
// structure of the test.
use std::fmt;
struct Dt<A: fmt::Debug>(&'static str, A);
struct Dr<'a, B:'a+fmt::Debug>(&'static str, &'a B);
struct Pt<A: fmt::Debug, B: fmt::Debug>(&'static str, A, B);
struct Pr<'a, 'b, B:'a+'b+fmt::Debug>(&'static str, &'a B, &'b B);
struct St<A: fmt::Debug>(&'static str, A);
struct Sr<'a, B:'a+fmt::Debug>(&'static str, &'a B);
impl<A: fmt::Debug> Drop for Dt<A> {
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<B: fmt::Debug, #[may_dangle] A: fmt::Debug> Drop for Pt<A, B> {
// (unsafe to access self.1 due to #[may_dangle] on A)
fn drop(&mut self) { println!("drop {} {:?}", self.0, self.2); }
}
unsafe impl<'b, #[may_dangle] 'a, 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); }
}
fn main() { #![rustc_error] // rust-lang/rust#49855
use std::cell::Cell;
let c_long;
let (c, mut dt, mut dr, mut pt, mut pr, st, sr, c_shortest)
: (Cell<_>, Dt<_>, Dr<_>, Pt<_, _>, Pr<_>, St<_>, Sr<_>, Cell<_>);
c_long = Cell::new(1);
c = Cell::new(1);
c_shortest = Cell::new(1);
// No error: sufficiently long-lived state can be referenced in dtors
dt = Dt("dt", &c_long);
dr = Dr("dr", &c_long);
// Error: destructor order imprecisely modelled
dt = Dt("dt", &c);
//~^ ERROR `c` does not live long enough
dr = Dr("dr", &c);
//~^ ERROR `c` does not live long enough
// Error: `c_shortest` dies too soon for the references in dtors to be valid.
dt = Dt("dt", &c_shortest);
//~^ ERROR `c_shortest` does not live long enough
dr = Dr("dr", &c_shortest);
//~^ ERROR `c_shortest` does not live long enough
// No error: Drop impl asserts .1 (A and &'a _) are not accessed
pt = Pt("pt", &c_shortest, &c_long);
pr = Pr("pr", &c_shortest, &c_long);
// Error: Drop impl's assertion does not apply to `B` nor `&'b _`
pt = Pt("pt", &c_long, &c_shortest);
//~^ ERROR `c_shortest` does not live long enough
pr = Pr("pr", &c_long, &c_shortest);
//~^ ERROR `c_shortest` does not live long enough
// No error: St and Sr have no destructor.
st = St("st", &c_shortest);
sr = Sr("sr", &c_shortest);
println!("{:?}", (dt.0, dr.0, pt.0, pr.0, st.0, sr.0));
}