From 797d8ea4789c64bb20869fa7fb0c15e2c09432cf Mon Sep 17 00:00:00 2001 From: Tim Date: Thu, 28 Feb 2019 07:32:13 +0100 Subject: [PATCH 1/2] 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"` --- src/libcore/ptr.rs | 8 +++--- src/test/run-pass/consts/const-ptr-nonnull.rs | 17 +++++++++++++ src/test/run-pass/consts/const-ptr-unique.rs | 15 +++++++++++ src/test/ui/consts/const-ptr-nonnull.rs | 11 ++++++++ src/test/ui/consts/const-ptr-nonnull.stderr | 25 +++++++++++++++++++ src/test/ui/consts/const-ptr-unique.rs | 10 ++++++++ src/test/ui/consts/const-ptr-unique.stderr | 14 +++++++++++ 7 files changed, 97 insertions(+), 3 deletions(-) create mode 100644 src/test/run-pass/consts/const-ptr-nonnull.rs create mode 100644 src/test/run-pass/consts/const-ptr-unique.rs create mode 100644 src/test/ui/consts/const-ptr-nonnull.rs create mode 100644 src/test/ui/consts/const-ptr-nonnull.stderr create mode 100644 src/test/ui/consts/const-ptr-unique.rs create mode 100644 src/test/ui/consts/const-ptr-unique.stderr diff --git a/src/libcore/ptr.rs b/src/libcore/ptr.rs index 866c8d0896b3c..3e1773ff9d25c 100644 --- a/src/libcore/ptr.rs +++ b/src/libcore/ptr.rs @@ -2790,7 +2790,7 @@ impl Unique { } /// Acquires the underlying `*mut` pointer. - pub fn as_ptr(self) -> *mut T { + pub const fn as_ptr(self) -> *mut T { self.pointer as *mut T } @@ -2903,7 +2903,8 @@ impl NonNull { /// some other means. #[stable(feature = "nonnull", since = "1.25.0")] #[inline] - pub fn dangling() -> Self { + #[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_ptr_nonnull"))] + pub const fn dangling() -> Self { unsafe { let ptr = mem::align_of::() as *mut T; NonNull::new_unchecked(ptr) @@ -2966,7 +2967,8 @@ impl NonNull { /// Cast to a pointer of another type #[stable(feature = "nonnull_cast", since = "1.27.0")] #[inline] - pub fn cast(self) -> NonNull { + #[cfg_attr(not(stage0), rustc_const_unstable(feature = "const_ptr_nonnull"))] + pub const fn cast(self) -> NonNull { unsafe { NonNull::new_unchecked(self.as_ptr() as *mut U) } diff --git a/src/test/run-pass/consts/const-ptr-nonnull.rs b/src/test/run-pass/consts/const-ptr-nonnull.rs new file mode 100644 index 0000000000000..91624e92fbe75 --- /dev/null +++ b/src/test/run-pass/consts/const-ptr-nonnull.rs @@ -0,0 +1,17 @@ +// run-pass + +#![feature(const_ptr_nonnull)] + +use std::ptr::NonNull; + +const DANGLING: NonNull = NonNull::dangling(); +const CASTED: NonNull = NonNull::cast(NonNull::::dangling()); + +fn ident(ident: T) -> T { + ident +} + +pub fn main() { + assert_eq!(DANGLING, ident(NonNull::dangling())); + assert_eq!(CASTED, ident(NonNull::dangling())); +} diff --git a/src/test/run-pass/consts/const-ptr-unique.rs b/src/test/run-pass/consts/const-ptr-unique.rs new file mode 100644 index 0000000000000..eb371ab184166 --- /dev/null +++ b/src/test/run-pass/consts/const-ptr-unique.rs @@ -0,0 +1,15 @@ +// run-pass + +#![feature(ptr_internals)] + +use std::ptr::Unique; + +const PTR: *mut u32 = Unique::empty().as_ptr(); + +fn ident(ident: T) -> T { + ident +} + +pub fn main() { + assert_eq!(PTR, ident(Unique::::empty().as_ptr())); +} diff --git a/src/test/ui/consts/const-ptr-nonnull.rs b/src/test/ui/consts/const-ptr-nonnull.rs new file mode 100644 index 0000000000000..54e743aa32e23 --- /dev/null +++ b/src/test/ui/consts/const-ptr-nonnull.rs @@ -0,0 +1,11 @@ +use std::ptr::NonNull; + +fn main() { + let x: &'static NonNull = &(NonNull::dangling()); + //~^ ERROR borrowed value does not live long enough + + let mut i: i32 = 10; + let non_null = NonNull::new(&mut i).unwrap(); + let x: &'static NonNull = &(non_null.cast()); + //~^ ERROR borrowed value does not live long enough +} diff --git a/src/test/ui/consts/const-ptr-nonnull.stderr b/src/test/ui/consts/const-ptr-nonnull.stderr new file mode 100644 index 0000000000000..a9476dda6d320 --- /dev/null +++ b/src/test/ui/consts/const-ptr-nonnull.stderr @@ -0,0 +1,25 @@ +error[E0597]: borrowed value does not live long enough + --> $DIR/const-ptr-nonnull.rs:4:37 + | +LL | let x: &'static NonNull = &(NonNull::dangling()); + | ^^^^^^^^^^^^^^^^^^^^^ temporary value does not live long enough +... +LL | } + | - temporary value only lives until here + | + = note: borrowed value must be valid for the static lifetime... + +error[E0597]: borrowed value does not live long enough + --> $DIR/const-ptr-nonnull.rs:9:37 + | +LL | let x: &'static NonNull = &(non_null.cast()); + | ^^^^^^^^^^^^^^^^^ temporary value does not live long enough +LL | //~^ ERROR borrowed value does not live long enough +LL | } + | - temporary value only lives until here + | + = note: borrowed value must be valid for the static lifetime... + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0597`. diff --git a/src/test/ui/consts/const-ptr-unique.rs b/src/test/ui/consts/const-ptr-unique.rs new file mode 100644 index 0000000000000..be44a24181606 --- /dev/null +++ b/src/test/ui/consts/const-ptr-unique.rs @@ -0,0 +1,10 @@ +#![feature(ptr_internals)] + +use std::ptr::Unique; + +fn main() { + let mut i: u32 = 10; + let unique = Unique::new(&mut i).unwrap(); + let x: &'static *mut u32 = &(unique.as_ptr()); + //~^ ERROR borrowed value does not live long enough +} diff --git a/src/test/ui/consts/const-ptr-unique.stderr b/src/test/ui/consts/const-ptr-unique.stderr new file mode 100644 index 0000000000000..141465bf184d0 --- /dev/null +++ b/src/test/ui/consts/const-ptr-unique.stderr @@ -0,0 +1,14 @@ +error[E0597]: borrowed value does not live long enough + --> $DIR/const-ptr-unique.rs:8:33 + | +LL | let x: &'static *mut u32 = &(unique.as_ptr()); + | ^^^^^^^^^^^^^^^^^ temporary value does not live long enough +LL | //~^ ERROR borrowed value does not live long enough +LL | } + | - temporary value only lives until here + | + = note: borrowed value must be valid for the static lifetime... + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0597`. From 60a649ef6ecf905253507997211ebd081f298f24 Mon Sep 17 00:00:00 2001 From: Tim Date: Sun, 3 Mar 2019 23:43:46 +0100 Subject: [PATCH 2/2] Add .nll.stderr output --- .../ui/consts/const-ptr-nonnull.nll.stderr | 25 +++++++++++++++++++ .../ui/consts/const-ptr-unique.nll.stderr | 14 +++++++++++ 2 files changed, 39 insertions(+) create mode 100644 src/test/ui/consts/const-ptr-nonnull.nll.stderr create mode 100644 src/test/ui/consts/const-ptr-unique.nll.stderr diff --git a/src/test/ui/consts/const-ptr-nonnull.nll.stderr b/src/test/ui/consts/const-ptr-nonnull.nll.stderr new file mode 100644 index 0000000000000..6977e7fdc1183 --- /dev/null +++ b/src/test/ui/consts/const-ptr-nonnull.nll.stderr @@ -0,0 +1,25 @@ +error[E0716]: temporary value dropped while borrowed + --> $DIR/const-ptr-nonnull.rs:4:37 + | +LL | let x: &'static NonNull = &(NonNull::dangling()); + | --------------------- ^^^^^^^^^^^^^^^^^^^^^ creates a temporary which is freed while still in use + | | + | type annotation requires that borrow lasts for `'static` +... +LL | } + | - temporary value is freed at the end of this statement + +error[E0716]: temporary value dropped while borrowed + --> $DIR/const-ptr-nonnull.rs:9:37 + | +LL | let x: &'static NonNull = &(non_null.cast()); + | --------------------- ^^^^^^^^^^^^^^^^^ creates a temporary which is freed while still in use + | | + | type annotation requires that borrow lasts for `'static` +LL | //~^ ERROR borrowed value does not live long enough +LL | } + | - temporary value is freed at the end of this statement + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0716`. diff --git a/src/test/ui/consts/const-ptr-unique.nll.stderr b/src/test/ui/consts/const-ptr-unique.nll.stderr new file mode 100644 index 0000000000000..b201994c894e4 --- /dev/null +++ b/src/test/ui/consts/const-ptr-unique.nll.stderr @@ -0,0 +1,14 @@ +error[E0716]: temporary value dropped while borrowed + --> $DIR/const-ptr-unique.rs:8:33 + | +LL | let x: &'static *mut u32 = &(unique.as_ptr()); + | ----------------- ^^^^^^^^^^^^^^^^^ creates a temporary which is freed while still in use + | | + | type annotation requires that borrow lasts for `'static` +LL | //~^ ERROR borrowed value does not live long enough +LL | } + | - temporary value is freed at the end of this statement + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0716`.