Rollup merge of #97320 - usbalbin:stabilize_const_ptr_read, r=m-ou-se

Stabilize const_ptr_read

Stabilizes const_ptr_read, with tracking issue #80377

library/alloc/src/lib.rs

@@ -113,7 +113,6 @@
 #![feature(const_maybe_uninit_write)]
 #![feature(const_maybe_uninit_zeroed)]
 #![feature(const_pin)]
-#![feature(const_ptr_read)]
 #![feature(const_refs_to_cell)]
 #![feature(const_size_of_val)]
 #![feature(const_waker)]

library/core/src/intrinsics.rs

@@ -2260,7 +2260,7 @@ pub unsafe fn drop_in_place<T: ?Sized>(to_drop: *mut T) {
     /// This intrinsic can *only* be called where the pointer is a local without
     /// projections (`read_via_copy(ptr)`, not `read_via_copy(*ptr)`) so that it
     /// trivially obeys runtime-MIR rules about derefs in operands.
-    #[rustc_const_unstable(feature = "const_ptr_read", issue = "80377")]
+    #[rustc_const_stable(feature = "const_ptr_read", since = "CURRENT_RUSTC_VERSION")]
     #[rustc_nounwind]
     pub fn read_via_copy<T>(ptr: *const T) -> T;
 

library/core/src/lib.rs

@@ -140,7 +140,6 @@
 #![feature(const_pointer_is_aligned)]
 #![feature(const_ptr_as_ref)]
 #![feature(const_ptr_is_null)]
-#![feature(const_ptr_read)]
 #![feature(const_ptr_sub_ptr)]
 #![feature(const_ptr_write)]
 #![feature(const_raw_ptr_comparison)]

library/core/src/ptr/const_ptr.rs

@@ -1195,7 +1195,7 @@ pub const fn wrapping_byte_sub(self, count: usize) -> Self {
     ///
     /// [`ptr::read`]: crate::ptr::read()
     #[stable(feature = "pointer_methods", since = "1.26.0")]
-    #[rustc_const_unstable(feature = "const_ptr_read", issue = "80377")]
+    #[rustc_const_stable(feature = "const_ptr_read", since = "CURRENT_RUSTC_VERSION")]
     #[inline]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     pub const unsafe fn read(self) -> T
@@ -1236,7 +1236,7 @@ pub unsafe fn read_volatile(self) -> T
     ///
     /// [`ptr::read_unaligned`]: crate::ptr::read_unaligned()
     #[stable(feature = "pointer_methods", since = "1.26.0")]
-    #[rustc_const_unstable(feature = "const_ptr_read", issue = "80377")]
+    #[rustc_const_stable(feature = "const_ptr_read", since = "CURRENT_RUSTC_VERSION")]
     #[inline]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     pub const unsafe fn read_unaligned(self) -> T

library/core/src/ptr/mod.rs

@@ -1133,7 +1133,8 @@ macro_rules! attempt_swap_as_chunks {
 /// [valid]: self#safety
 #[inline]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_const_unstable(feature = "const_ptr_read", issue = "80377")]
+#[rustc_const_stable(feature = "const_ptr_read", since = "CURRENT_RUSTC_VERSION")]
+#[rustc_allow_const_fn_unstable(const_mut_refs, const_maybe_uninit_as_mut_ptr)]
 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
 pub const unsafe fn read<T>(src: *const T) -> T {
     // It would be semantically correct to implement this via `copy_nonoverlapping`
@@ -1249,7 +1250,8 @@ macro_rules! attempt_swap_as_chunks {
 /// ```
 #[inline]
 #[stable(feature = "ptr_unaligned", since = "1.17.0")]
-#[rustc_const_unstable(feature = "const_ptr_read", issue = "80377")]
+#[rustc_const_stable(feature = "const_ptr_read", since = "CURRENT_RUSTC_VERSION")]
+#[rustc_allow_const_fn_unstable(const_mut_refs, const_maybe_uninit_as_mut_ptr)]
 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
 pub const unsafe fn read_unaligned<T>(src: *const T) -> T {
     let mut tmp = MaybeUninit::<T>::uninit();

library/core/src/ptr/mut_ptr.rs

@@ -1305,7 +1305,7 @@ pub const fn wrapping_byte_sub(self, count: usize) -> Self {
     ///
     /// [`ptr::read`]: crate::ptr::read()
     #[stable(feature = "pointer_methods", since = "1.26.0")]
-    #[rustc_const_unstable(feature = "const_ptr_read", issue = "80377")]
+    #[rustc_const_stable(feature = "const_ptr_read", since = "CURRENT_RUSTC_VERSION")]
     #[inline(always)]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     pub const unsafe fn read(self) -> T
@@ -1346,7 +1346,7 @@ pub unsafe fn read_volatile(self) -> T
     ///
     /// [`ptr::read_unaligned`]: crate::ptr::read_unaligned()
     #[stable(feature = "pointer_methods", since = "1.26.0")]
-    #[rustc_const_unstable(feature = "const_ptr_read", issue = "80377")]
+    #[rustc_const_stable(feature = "const_ptr_read", since = "CURRENT_RUSTC_VERSION")]
     #[inline(always)]
     #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
     pub const unsafe fn read_unaligned(self) -> T

library/core/tests/lib.rs

@@ -18,7 +18,6 @@
 #![feature(const_pointer_byte_offsets)]
 #![feature(const_pointer_is_aligned)]
 #![feature(const_ptr_as_ref)]
-#![feature(const_ptr_read)]
 #![feature(const_ptr_write)]
 #![feature(const_trait_impl)]
 #![feature(const_likely)]

src/tools/miri/tests/fail/const-ub-checks.rs

@@ -1,4 +1,3 @@
-#![feature(const_ptr_read)]
 
 const UNALIGNED_READ: () = unsafe {
     let x = &[0u8; 4];

tests/ui/const-generics/issues/issue-105821.rs

@@ -1,7 +1,7 @@
 // check-pass
 
 #![allow(incomplete_features)]
-#![feature(adt_const_params, const_ptr_read, generic_const_exprs)]
+#![feature(adt_const_params, generic_const_exprs)]
 #![allow(dead_code)]
 
 const fn catone<const M: usize>(_a: &[u8; M]) -> [u8; M + 1]

tests/ui/const-ptr/out_of_bounds_read.rs

@@ -1,7 +1,5 @@
 // error-pattern: evaluation of constant value failed
 
-#![feature(const_ptr_read)]
-
 fn main() {
     use std::ptr;
 

tests/ui/const-ptr/out_of_bounds_read.stderr

@@ -6,7 +6,7 @@ error[E0080]: evaluation of constant value failed
 note: inside `std::ptr::read::<u32>`
   --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
 note: inside `_READ`
-  --> $DIR/out_of_bounds_read.rs:12:33
+  --> $DIR/out_of_bounds_read.rs:10:33
    |
 LL |     const _READ: u32 = unsafe { ptr::read(PAST_END_PTR) };
    |                                 ^^^^^^^^^^^^^^^^^^^^^^^
@@ -21,7 +21,7 @@ note: inside `std::ptr::read::<u32>`
 note: inside `ptr::const_ptr::<impl *const u32>::read`
   --> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
 note: inside `_CONST_READ`
-  --> $DIR/out_of_bounds_read.rs:13:39
+  --> $DIR/out_of_bounds_read.rs:11:39
    |
 LL |     const _CONST_READ: u32 = unsafe { PAST_END_PTR.read() };
    |                                       ^^^^^^^^^^^^^^^^^^^
@@ -36,7 +36,7 @@ note: inside `std::ptr::read::<u32>`
 note: inside `ptr::mut_ptr::<impl *mut u32>::read`
   --> $SRC_DIR/core/src/ptr/mut_ptr.rs:LL:COL
 note: inside `_MUT_READ`
-  --> $DIR/out_of_bounds_read.rs:14:37
+  --> $DIR/out_of_bounds_read.rs:12:37
    |
 LL |     const _MUT_READ: u32 = unsafe { (PAST_END_PTR as *mut u32).read() };
    |                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

tests/ui/consts/const-eval/ub-ref-ptr.rs

@@ -3,7 +3,6 @@
 // normalize-stderr-test "(the raw bytes of the constant) \(size: [0-9]*, align: [0-9]*\)" -> "$1 (size: $$SIZE, align: $$ALIGN)"
 // normalize-stderr-test "([0-9a-f][0-9a-f] |╾─*a(lloc)?[0-9]+(\+[a-z0-9]+)?─*╼ )+ *│.*" -> "HEX_DUMP"
 #![allow(invalid_value)]
-#![feature(const_ptr_read)]
 
 use std::mem;
 

tests/ui/consts/const-eval/ub-ref-ptr.stderr

@@ -1,5 +1,5 @@
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:16:1
+  --> $DIR/ub-ref-ptr.rs:15:1
    |
 LL | const UNALIGNED: &u16 = unsafe { mem::transmute(&[0u8; 4]) };
    | ^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered an unaligned reference (required 2 byte alignment but found 1)
@@ -10,7 +10,7 @@ LL | const UNALIGNED: &u16 = unsafe { mem::transmute(&[0u8; 4]) };
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:20:1
+  --> $DIR/ub-ref-ptr.rs:19:1
    |
 LL | const UNALIGNED_BOX: Box<u16> = unsafe { mem::transmute(&[0u8; 4]) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered an unaligned box (required 2 byte alignment but found 1)
@@ -21,7 +21,7 @@ LL | const UNALIGNED_BOX: Box<u16> = unsafe { mem::transmute(&[0u8; 4]) };
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:24:1
+  --> $DIR/ub-ref-ptr.rs:23:1
    |
 LL | const NULL: &u16 = unsafe { mem::transmute(0usize) };
    | ^^^^^^^^^^^^^^^^ constructing invalid value: encountered a null reference
@@ -32,7 +32,7 @@ LL | const NULL: &u16 = unsafe { mem::transmute(0usize) };
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:27:1
+  --> $DIR/ub-ref-ptr.rs:26:1
    |
 LL | const NULL_BOX: Box<u16> = unsafe { mem::transmute(0usize) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a null box
@@ -43,7 +43,7 @@ LL | const NULL_BOX: Box<u16> = unsafe { mem::transmute(0usize) };
            }
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-ref-ptr.rs:34:1
+  --> $DIR/ub-ref-ptr.rs:33:1
    |
 LL | const REF_AS_USIZE: usize = unsafe { mem::transmute(&0) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -52,7 +52,7 @@ LL | const REF_AS_USIZE: usize = unsafe { mem::transmute(&0) };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-ref-ptr.rs:37:39
+  --> $DIR/ub-ref-ptr.rs:36:39
    |
 LL | const REF_AS_USIZE_SLICE: &[usize] = &[unsafe { mem::transmute(&0) }];
    |                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -61,13 +61,13 @@ LL | const REF_AS_USIZE_SLICE: &[usize] = &[unsafe { mem::transmute(&0) }];
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 note: erroneous constant used
-  --> $DIR/ub-ref-ptr.rs:37:38
+  --> $DIR/ub-ref-ptr.rs:36:38
    |
 LL | const REF_AS_USIZE_SLICE: &[usize] = &[unsafe { mem::transmute(&0) }];
    |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-ref-ptr.rs:40:86
+  --> $DIR/ub-ref-ptr.rs:39:86
    |
 LL | const REF_AS_USIZE_BOX_SLICE: Box<[usize]> = unsafe { mem::transmute::<&[usize], _>(&[mem::transmute(&0)]) };
    |                                                                                      ^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -76,13 +76,13 @@ LL | const REF_AS_USIZE_BOX_SLICE: Box<[usize]> = unsafe { mem::transmute::<&[us
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 note: erroneous constant used
-  --> $DIR/ub-ref-ptr.rs:40:85
+  --> $DIR/ub-ref-ptr.rs:39:85
    |
 LL | const REF_AS_USIZE_BOX_SLICE: Box<[usize]> = unsafe { mem::transmute::<&[usize], _>(&[mem::transmute(&0)]) };
    |                                                                                     ^^^^^^^^^^^^^^^^^^^^^
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:43:1
+  --> $DIR/ub-ref-ptr.rs:42:1
    |
 LL | const USIZE_AS_REF: &'static u8 = unsafe { mem::transmute(1337usize) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a dangling reference (0x539[noalloc] has no provenance)
@@ -93,7 +93,7 @@ LL | const USIZE_AS_REF: &'static u8 = unsafe { mem::transmute(1337usize) };
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:46:1
+  --> $DIR/ub-ref-ptr.rs:45:1
    |
 LL | const USIZE_AS_BOX: Box<u8> = unsafe { mem::transmute(1337usize) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a dangling box (0x539[noalloc] has no provenance)
@@ -104,13 +104,13 @@ LL | const USIZE_AS_BOX: Box<u8> = unsafe { mem::transmute(1337usize) };
            }
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-ref-ptr.rs:49:41
+  --> $DIR/ub-ref-ptr.rs:48:41
    |
 LL | const UNINIT_PTR: *const i32 = unsafe { MaybeUninit { uninit: () }.init };
    |                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:53:1
+  --> $DIR/ub-ref-ptr.rs:52:1
    |
 LL | const NULL_FN_PTR: fn() = unsafe { mem::transmute(0usize) };
    | ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered null pointer, but expected a function pointer
@@ -121,13 +121,13 @@ LL | const NULL_FN_PTR: fn() = unsafe { mem::transmute(0usize) };
            }
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-ref-ptr.rs:55:38
+  --> $DIR/ub-ref-ptr.rs:54:38
    |
 LL | const UNINIT_FN_PTR: fn() = unsafe { MaybeUninit { uninit: () }.init };
    |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:58:1
+  --> $DIR/ub-ref-ptr.rs:57:1
    |
 LL | const DANGLING_FN_PTR: fn() = unsafe { mem::transmute(13usize) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered 0xd[noalloc], but expected a function pointer
@@ -138,7 +138,7 @@ LL | const DANGLING_FN_PTR: fn() = unsafe { mem::transmute(13usize) };
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:60:1
+  --> $DIR/ub-ref-ptr.rs:59:1
    |
 LL | const DATA_FN_PTR: fn() = unsafe { mem::transmute(&13) };
    | ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered alloc41, but expected a function pointer
@@ -158,7 +158,7 @@ note: inside `std::ptr::read::<u32>`
 note: inside `ptr::const_ptr::<impl *const u32>::read`
   --> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
 note: inside `UNALIGNED_READ`
-  --> $DIR/ub-ref-ptr.rs:67:5
+  --> $DIR/ub-ref-ptr.rs:66:5
    |
 LL |     ptr.read();
    |     ^^^^^^^^^^

tests/ui/consts/extra-const-ub/detect-extra-ub.rs

@@ -1,7 +1,6 @@
 // revisions: no_flag with_flag
 // [no_flag] check-pass
 // [with_flag] compile-flags: -Zextra-const-ub-checks
-#![feature(const_ptr_read)]
 
 use std::mem::transmute;
 

tests/ui/consts/extra-const-ub/detect-extra-ub.with_flag.stderr

@@ -1,11 +1,11 @@
 error[E0080]: evaluation of constant value failed
-  --> $DIR/detect-extra-ub.rs:9:20
+  --> $DIR/detect-extra-ub.rs:8:20
    |
 LL |     let _x: bool = transmute(3u8);
    |                    ^^^^^^^^^^^^^^ constructing invalid value: encountered 0x03, but expected a boolean
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/detect-extra-ub.rs:15:21
+  --> $DIR/detect-extra-ub.rs:14:21
    |
 LL |     let _x: usize = transmute(&3u8);
    |                     ^^^^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -14,7 +14,7 @@ LL |     let _x: usize = transmute(&3u8);
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/detect-extra-ub.rs:21:30
+  --> $DIR/detect-extra-ub.rs:20:30
    |
 LL |     let _x: (usize, usize) = transmute(x);
    |                              ^^^^^^^^^^^^ unable to turn pointer into raw bytes
@@ -23,7 +23,7 @@ LL |     let _x: (usize, usize) = transmute(x);
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/detect-extra-ub.rs:26:20
+  --> $DIR/detect-extra-ub.rs:25:20
    |
 LL |     let _x: &u32 = transmute(&[0u8; 4]);
    |                    ^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered an unaligned reference (required 4 byte alignment but found 1)

tests/ui/consts/issue-miri-1910.rs

@@ -1,6 +1,5 @@
 // error-pattern unable to turn pointer into raw bytes
 // normalize-stderr-test: "alloc[0-9]+\+0x[a-z0-9]+" -> "ALLOC"
-#![feature(const_ptr_read)]
 
 const C: () = unsafe {
     let foo = Some(&42 as *const i32);

tests/ui/consts/issue-miri-1910.stderr

@@ -10,7 +10,7 @@ note: inside `std::ptr::read::<u8>`
 note: inside `ptr::const_ptr::<impl *const u8>::read`
   --> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
 note: inside `C`
-  --> $DIR/issue-miri-1910.rs:8:5
+  --> $DIR/issue-miri-1910.rs:7:5
    |
 LL |     (&foo as *const _ as *const u8).add(one_and_a_half_pointers).read();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^