1 // Copyright 2016 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 #![feature(dropck_eyepatch, rustc_attrs)]
13 // The point of this test is to test uses of `#[may_dangle]` attribute
14 // where the formal declaration order (in the impl generics) does not
15 // match the actual usage order (in the type instantiation).
17 // See also dropck-eyepatch.rs for more information about the general
18 // structure of the test.
22 struct Dt<A: fmt::Debug>(&'static str, A);
23 struct Dr<'a, B:'a+fmt::Debug>(&'static str, &'a B);
24 struct Pt<A: fmt::Debug, B: fmt::Debug>(&'static str, A, B);
25 struct Pr<'a, 'b, B:'a+'b+fmt::Debug>(&'static str, &'a B, &'b B);
26 struct St<A: fmt::Debug>(&'static str, A);
27 struct Sr<'a, B:'a+fmt::Debug>(&'static str, &'a B);
29 impl<A: fmt::Debug> Drop for Dt<A> {
30 fn drop(&mut self) { println!("drop {} {:?}", self.0, self.1); }
32 impl<'a, B: fmt::Debug> Drop for Dr<'a, B> {
33 fn drop(&mut self) { println!("drop {} {:?}", self.0, self.1); }
35 unsafe impl<B: fmt::Debug, #[may_dangle] A: fmt::Debug> Drop for Pt<A, B> {
36 // (unsafe to access self.1 due to #[may_dangle] on A)
37 fn drop(&mut self) { println!("drop {} {:?}", self.0, self.2); }
39 unsafe impl<'b, #[may_dangle] 'a, B: fmt::Debug> Drop for Pr<'a, 'b, B> {
40 // (unsafe to access self.1 due to #[may_dangle] on 'a)
41 fn drop(&mut self) { println!("drop {} {:?}", self.0, self.2); }
44 fn main() { #![rustc_error] // rust-lang/rust#49855
47 let (c, mut dt, mut dr, mut pt, mut pr, st, sr, c_shortest)
48 : (Cell<_>, Dt<_>, Dr<_>, Pt<_, _>, Pr<_>, St<_>, Sr<_>, Cell<_>);
49 c_long = Cell::new(1);
51 c_shortest = Cell::new(1);
53 // No error: sufficiently long-lived state can be referenced in dtors
54 dt = Dt("dt", &c_long);
55 dr = Dr("dr", &c_long);
57 // Error: destructor order imprecisely modelled
59 //~^ ERROR `c` does not live long enough
61 //~^ ERROR `c` does not live long enough
63 // Error: `c_shortest` dies too soon for the references in dtors to be valid.
64 dt = Dt("dt", &c_shortest);
65 //~^ ERROR `c_shortest` does not live long enough
66 dr = Dr("dr", &c_shortest);
67 //~^ ERROR `c_shortest` does not live long enough
69 // No error: Drop impl asserts .1 (A and &'a _) are not accessed
70 pt = Pt("pt", &c_shortest, &c_long);
71 pr = Pr("pr", &c_shortest, &c_long);
73 // Error: Drop impl's assertion does not apply to `B` nor `&'b _`
74 pt = Pt("pt", &c_long, &c_shortest);
75 //~^ ERROR `c_shortest` does not live long enough
76 pr = Pr("pr", &c_long, &c_shortest);
77 //~^ ERROR `c_shortest` does not live long enough
79 // No error: St and Sr have no destructor.
80 st = St("st", &c_shortest);
81 sr = Sr("sr", &c_shortest);
83 println!("{:?}", (dt.0, dr.0, pt.0, pr.0, st.0, sr.0));