mirror of
https://github.com/rust-lang/rust.git
synced 2024-11-26 00:34:06 +00:00
36 lines
804 B
Rust
36 lines
804 B
Rust
// rust-lang/rust#60431: This is a scenario where to determine the size of
|
|
// `&Ref<Obstack>`, we need to know the concrete type of the last field in
|
|
// `Ref<Obstack>` (i.e. its "struct tail"), and determining that concrete type
|
|
// requires normalizing `Obstack::Dyn`.
|
|
//
|
|
// The old "struct tail" computation did not perform such normalization, and so
|
|
// the compiler would ICE when trying to figure out if `Ref<Obstack>` is a
|
|
// dynamically-sized type (DST).
|
|
|
|
// run-pass
|
|
|
|
use std::mem;
|
|
|
|
pub trait Arena {
|
|
type Dyn : ?Sized;
|
|
}
|
|
|
|
pub struct DynRef {
|
|
_dummy: [()],
|
|
}
|
|
|
|
pub struct Ref<A: Arena> {
|
|
_value: u8,
|
|
_dyn_arena: A::Dyn,
|
|
}
|
|
|
|
pub struct Obstack;
|
|
|
|
impl Arena for Obstack {
|
|
type Dyn = DynRef;
|
|
}
|
|
|
|
fn main() {
|
|
assert_eq!(mem::size_of::<&Ref<Obstack>>(), mem::size_of::<&[()]>());
|
|
}
|