82 lines
2.5 KiB
Rust
82 lines
2.5 KiB
Rust
use core::pin::Pin;
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#[test]
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fn pin_const() {
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// test that the methods of `Pin` are usable in a const context
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const POINTER: &'static usize = &2;
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const PINNED: Pin<&'static usize> = Pin::new(POINTER);
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const PINNED_UNCHECKED: Pin<&'static usize> = unsafe { Pin::new_unchecked(POINTER) };
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assert_eq!(PINNED_UNCHECKED, PINNED);
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const INNER: &'static usize = Pin::into_inner(PINNED);
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assert_eq!(INNER, POINTER);
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const INNER_UNCHECKED: &'static usize = unsafe { Pin::into_inner_unchecked(PINNED) };
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assert_eq!(INNER_UNCHECKED, POINTER);
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const REF: &'static usize = PINNED.get_ref();
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assert_eq!(REF, POINTER);
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const INT: u8 = 42;
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const STATIC_REF: Pin<&'static u8> = Pin::static_ref(&INT);
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assert_eq!(*STATIC_REF, INT);
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// Note: `pin_mut_const` tests that the methods of `Pin<&mut T>` are usable in a const context.
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// A const fn is used because `&mut` is not (yet) usable in constants.
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const fn pin_mut_const() {
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let _ = Pin::new(&mut 2).into_ref();
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let _ = Pin::new(&mut 2).get_mut();
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let _ = unsafe { Pin::new(&mut 2).get_unchecked_mut() };
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}
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pin_mut_const();
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}
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#[allow(unused)]
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mod pin_coerce_unsized {
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use core::cell::{Cell, RefCell, UnsafeCell};
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use core::pin::Pin;
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use core::ptr::NonNull;
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pub trait MyTrait {}
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impl MyTrait for String {}
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// These Pins should continue to compile.
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// Do note that these instances of Pin types cannot be used
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// meaningfully because all methods require a Deref/DerefMut
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// bounds on the pointer type and Cell, RefCell and UnsafeCell
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// do not implement Deref/DerefMut.
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pub fn cell(arg: Pin<Cell<Box<String>>>) -> Pin<Cell<Box<dyn MyTrait>>> {
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arg
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}
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pub fn ref_cell(arg: Pin<RefCell<Box<String>>>) -> Pin<RefCell<Box<dyn MyTrait>>> {
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arg
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}
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pub fn unsafe_cell(arg: Pin<UnsafeCell<Box<String>>>) -> Pin<UnsafeCell<Box<dyn MyTrait>>> {
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arg
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}
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// These sensible Pin coercions are possible.
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pub fn pin_mut_ref(arg: Pin<&mut String>) -> Pin<&mut dyn MyTrait> {
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arg
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}
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pub fn pin_ref(arg: Pin<&String>) -> Pin<&dyn MyTrait> {
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arg
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}
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pub fn pin_ptr(arg: Pin<*const String>) -> Pin<*const dyn MyTrait> {
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arg
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}
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pub fn pin_ptr_mut(arg: Pin<*mut String>) -> Pin<*mut dyn MyTrait> {
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arg
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}
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pub fn pin_non_null(arg: Pin<NonNull<String>>) -> Pin<NonNull<dyn MyTrait>> {
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arg
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}
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pub fn nesting_pins(arg: Pin<Pin<&String>>) -> Pin<Pin<&dyn MyTrait>> {
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arg
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}
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}
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