blob: a36f26f02e9f46ed8df2b46784a69d7823211ee3 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
|
// Checking the `Send` bound in `main` requires:
//
// checking <C<'static> as Y>::P: Send
// which normalizes to Box<X<C<'?1>>>: Send
// which needs X<C<'?1>>: Send
// which needs <C<'?1> as Y>::P: Send
//
// At this point we used to normalize the predicate to `Box<X<C<'?2>>>: Send`
// and continue in a loop where we created new region variables to the
// recursion limit. To avoid this we now "canonicalize" region variables to
// lowest unified region vid. This means we instead have to prove
// `Box<X<C<'?1>>>: Send`, which we can because auto traits are coinductive.
// check-pass
// Avoid a really long error message if this regresses.
#![recursion_limit="20"]
trait Y {
type P;
}
impl<'a> Y for C<'a> {
type P = Box<X<C<'a>>>;
}
struct C<'a>(&'a ());
struct X<T: Y>(T::P);
fn is_send<S: Send>() {}
fn main() {
is_send::<X<C<'static>>>();
}
|
