81 lines
2.7 KiB
Rust
81 lines
2.7 KiB
Rust
//@ run-pass
|
|
#![feature(dropck_eyepatch)]
|
|
#![allow(non_local_definitions)]
|
|
|
|
// 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.
|
|
|
|
trait Foo { fn foo(&self, _: &str); }
|
|
|
|
struct Dt<A: Foo>(&'static str, A);
|
|
struct Dr<'a, B:'a+Foo>(&'static str, &'a B);
|
|
struct Pt<A: Foo, B: Foo>(&'static str, #[allow(dead_code)] A, B);
|
|
struct Pr<'a, 'b, B:'a+'b+Foo>(&'static str, #[allow(dead_code)] &'a B, &'b B);
|
|
struct St<A: Foo>(&'static str, #[allow(dead_code)] A);
|
|
struct Sr<'a, B:'a+Foo>(&'static str, #[allow(dead_code)] &'a B);
|
|
|
|
impl<A: Foo> Drop for Dt<A> {
|
|
fn drop(&mut self) { println!("drop {}", self.0); self.1.foo(self.0); }
|
|
}
|
|
impl<'a, B: Foo> Drop for Dr<'a, B> {
|
|
fn drop(&mut self) { println!("drop {}", self.0); self.1.foo(self.0); }
|
|
}
|
|
unsafe impl<B: Foo, #[may_dangle] A: Foo> 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.foo(self.0); }
|
|
}
|
|
unsafe impl<'b, #[may_dangle] 'a, B: Foo> 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.foo(self.0); }
|
|
}
|
|
|
|
fn main() {
|
|
use std::cell::RefCell;
|
|
|
|
impl Foo for RefCell<String> {
|
|
fn foo(&self, s: &str) {
|
|
let s2 = format!("{}|{}", *self.borrow(), s);
|
|
*self.borrow_mut() = s2;
|
|
}
|
|
}
|
|
|
|
impl<'a, T:Foo> Foo for &'a T {
|
|
fn foo(&self, s: &str) {
|
|
(*self).foo(s);
|
|
}
|
|
}
|
|
|
|
struct CheckOnDrop(RefCell<String>, &'static str);
|
|
impl Drop for CheckOnDrop {
|
|
fn drop(&mut self) { assert_eq!(*self.0.borrow(), self.1); }
|
|
}
|
|
|
|
let c_long;
|
|
let (c, dt, dr, pt, pr, st, sr)
|
|
: (CheckOnDrop, Dt<_>, Dr<_>, Pt<_, _>, Pr<_>, St<_>, Sr<_>);
|
|
c_long = CheckOnDrop(RefCell::new("c_long".to_string()),
|
|
"c_long|pr|pt|dr|dt");
|
|
c = CheckOnDrop(RefCell::new("c".to_string()),
|
|
"c");
|
|
|
|
// No error: sufficiently long-lived state can be referenced in dtors
|
|
dt = Dt("dt", &c_long.0);
|
|
dr = Dr("dr", &c_long.0);
|
|
|
|
// No error: Drop impl asserts .1 (A and &'a _) are not accessed
|
|
pt = Pt("pt", &c.0, &c_long.0);
|
|
pr = Pr("pr", &c.0, &c_long.0);
|
|
|
|
// No error: St and Sr have no destructor.
|
|
st = St("st", &c.0);
|
|
sr = Sr("sr", &c.0);
|
|
|
|
println!("{:?}", (dt.0, dr.0, pt.0, pr.0, st.0, sr.0));
|
|
assert_eq!(*c_long.0.borrow(), "c_long");
|
|
assert_eq!(*c.0.borrow(), "c");
|
|
}
|