mirror of
https://github.com/rust-lang/rust.git
synced 2025-10-02 18:27:37 +00:00
31 lines
614 B
Rust
31 lines
614 B
Rust
//@ check-pass
|
|
//@ edition:2018
|
|
|
|
#![feature(ptr_metadata)]
|
|
#![feature(type_alias_impl_trait)]
|
|
|
|
pub type Opaque = impl std::future::Future;
|
|
|
|
#[define_opaque(Opaque)]
|
|
fn opaque() -> Opaque {
|
|
async {}
|
|
}
|
|
|
|
fn a<T>() {
|
|
// type parameter T is known to be sized
|
|
is_thin::<T>();
|
|
// tail of ADT (which is a type param) is known to be sized
|
|
is_thin::<std::cell::Cell<T>>();
|
|
// opaque type is known to be sized
|
|
is_thin::<Opaque>();
|
|
}
|
|
|
|
fn a2<T: Iterator>() {
|
|
// associated type is known to be sized
|
|
is_thin::<T::Item>();
|
|
}
|
|
|
|
fn is_thin<T: std::ptr::Pointee<Metadata = ()>>() {}
|
|
|
|
fn main() {}
|