mirror of
https://github.com/rust-lang/rust
synced 2024-10-01 22:34:35 +00:00
Make Unique::as_ptr
, NonNull::dangling
and NonNull::cast
const
Make `Unique::as_ptr` const without feature attribute as it's unstable Make `NonNull::dangling` and `NonNull::cast` const with `feature = "const_ptr_nonnull"`
This commit is contained in:
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@ -2790,7 +2790,7 @@ pub fn new(ptr: *mut T) -> Option<Self> {
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}
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/// Acquires the underlying `*mut` pointer.
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pub fn as_ptr(self) -> *mut T {
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pub const fn as_ptr(self) -> *mut T {
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self.pointer as *mut T
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}
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@ -2903,7 +2903,8 @@ impl<T: Sized> NonNull<T> {
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/// some other means.
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#[stable(feature = "nonnull", since = "1.25.0")]
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#[inline]
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pub fn dangling() -> Self {
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#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_ptr_nonnull"))]
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pub const fn dangling() -> Self {
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unsafe {
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let ptr = mem::align_of::<T>() as *mut T;
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NonNull::new_unchecked(ptr)
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@ -2966,7 +2967,8 @@ pub unsafe fn as_mut(&mut self) -> &mut T {
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/// Cast to a pointer of another type
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#[stable(feature = "nonnull_cast", since = "1.27.0")]
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#[inline]
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pub fn cast<U>(self) -> NonNull<U> {
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#[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_ptr_nonnull"))]
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pub const fn cast<U>(self) -> NonNull<U> {
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unsafe {
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NonNull::new_unchecked(self.as_ptr() as *mut U)
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}
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17
src/test/run-pass/consts/const-ptr-nonnull.rs
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17
src/test/run-pass/consts/const-ptr-nonnull.rs
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@ -0,0 +1,17 @@
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// run-pass
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#![feature(const_ptr_nonnull)]
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use std::ptr::NonNull;
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const DANGLING: NonNull<u32> = NonNull::dangling();
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const CASTED: NonNull<u32> = NonNull::cast(NonNull::<i32>::dangling());
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fn ident<T>(ident: T) -> T {
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ident
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}
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pub fn main() {
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assert_eq!(DANGLING, ident(NonNull::dangling()));
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assert_eq!(CASTED, ident(NonNull::dangling()));
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}
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15
src/test/run-pass/consts/const-ptr-unique.rs
Normal file
15
src/test/run-pass/consts/const-ptr-unique.rs
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@ -0,0 +1,15 @@
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// run-pass
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#![feature(ptr_internals)]
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use std::ptr::Unique;
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const PTR: *mut u32 = Unique::empty().as_ptr();
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fn ident<T>(ident: T) -> T {
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ident
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}
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pub fn main() {
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assert_eq!(PTR, ident(Unique::<u32>::empty().as_ptr()));
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}
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11
src/test/ui/consts/const-ptr-nonnull.rs
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11
src/test/ui/consts/const-ptr-nonnull.rs
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@ -0,0 +1,11 @@
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use std::ptr::NonNull;
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fn main() {
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let x: &'static NonNull<u32> = &(NonNull::dangling());
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//~^ ERROR borrowed value does not live long enough
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let mut i: i32 = 10;
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let non_null = NonNull::new(&mut i).unwrap();
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let x: &'static NonNull<u32> = &(non_null.cast());
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//~^ ERROR borrowed value does not live long enough
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}
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25
src/test/ui/consts/const-ptr-nonnull.stderr
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25
src/test/ui/consts/const-ptr-nonnull.stderr
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@ -0,0 +1,25 @@
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error[E0597]: borrowed value does not live long enough
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--> $DIR/const-ptr-nonnull.rs:4:37
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LL | let x: &'static NonNull<u32> = &(NonNull::dangling());
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| ^^^^^^^^^^^^^^^^^^^^^ temporary value does not live long enough
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...
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LL | }
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| - temporary value only lives until here
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= note: borrowed value must be valid for the static lifetime...
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error[E0597]: borrowed value does not live long enough
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--> $DIR/const-ptr-nonnull.rs:9:37
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LL | let x: &'static NonNull<u32> = &(non_null.cast());
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| ^^^^^^^^^^^^^^^^^ temporary value does not live long enough
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LL | //~^ ERROR borrowed value does not live long enough
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LL | }
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| - temporary value only lives until here
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= note: borrowed value must be valid for the static lifetime...
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error: aborting due to 2 previous errors
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For more information about this error, try `rustc --explain E0597`.
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10
src/test/ui/consts/const-ptr-unique.rs
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10
src/test/ui/consts/const-ptr-unique.rs
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@ -0,0 +1,10 @@
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#![feature(ptr_internals)]
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use std::ptr::Unique;
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fn main() {
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let mut i: u32 = 10;
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let unique = Unique::new(&mut i).unwrap();
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let x: &'static *mut u32 = &(unique.as_ptr());
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//~^ ERROR borrowed value does not live long enough
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}
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14
src/test/ui/consts/const-ptr-unique.stderr
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14
src/test/ui/consts/const-ptr-unique.stderr
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@ -0,0 +1,14 @@
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error[E0597]: borrowed value does not live long enough
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--> $DIR/const-ptr-unique.rs:8:33
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LL | let x: &'static *mut u32 = &(unique.as_ptr());
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| ^^^^^^^^^^^^^^^^^ temporary value does not live long enough
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LL | //~^ ERROR borrowed value does not live long enough
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LL | }
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| - temporary value only lives until here
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= note: borrowed value must be valid for the static lifetime...
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error: aborting due to previous error
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For more information about this error, try `rustc --explain E0597`.
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