fix CI; use assert_unsafe_precondition

Author: scottmcm

library/core/src/mem/valid_align.rs

@@ -1,4 +1,5 @@
 use crate::convert::TryFrom;
+use crate::intrinsics::assert_unsafe_precondition;
 use crate::num::NonZeroUsize;
 use crate::{cmp, fmt, hash, mem, num};
 
@@ -26,11 +27,12 @@ impl ValidAlign {
     /// It must *not* be zero.
     #[inline]
     pub(crate) const unsafe fn new_unchecked(align: usize) -> Self {
-        debug_assert!(align.is_power_of_two());
-
         // SAFETY: By precondition, this must be a power of two, and
         // our variants encompass all possible powers of two.
-        unsafe { mem::transmute::<usize, ValidAlign>(align) }
+        unsafe {
+            assert_unsafe_precondition!(align.is_power_of_two());
+            mem::transmute::<usize, ValidAlign>(align)
+        }
     }
 
     #[inline]

library/core/src/mem/valid_size.rs

@@ -1,4 +1,5 @@
 use crate::convert::TryFrom;
+use crate::intrinsics::assert_unsafe_precondition;
 use crate::{fmt, num};
 
 /// A type storing a possible object size (in bytes) in the rust abstract machine.
@@ -19,8 +20,6 @@ pub(crate) struct ValidSize(usize);
 
 const MAX_SIZE: usize = isize::MAX as usize;
 
-const _: () = unsafe { ValidSize::new_unchecked(MAX_SIZE); };
-
 impl ValidSize {
     /// Creates a `ValidSize` from a `usize` that fits in an `isize`.
     ///
@@ -31,10 +30,11 @@ impl ValidSize {
     /// Equivalently, it must not have its high bit set.
     #[inline]
     pub(crate) const unsafe fn new_unchecked(size: usize) -> Self {
-        debug_assert!(size <= MAX_SIZE);
-
         // SAFETY: By precondition, this must be within our validity invariant.
-        unsafe { ValidSize(size) }
+        unsafe {
+            assert_unsafe_precondition!(size <= MAX_SIZE);
+            ValidSize(size)
+        }
     }
 
     #[inline]

src/test/ui/consts/std/alloc.32bit.stderr

@@ -34,7 +34,7 @@ LL | const LAYOUT_SIZE_NEGATIVE_ONE: Layout = unsafe { Layout::from_size_align_u
 error[E0080]: it is undefined behavior to use this value
   --> $DIR/alloc.rs:21:1
    |
-LL | const LAYOUT_SIZE_HIGH_BIT: Layout = unsafe { Layout::from_size_align_unchecked((isize::MAX as usize) + 1, 1) };
+LL | const LAYOUT_SIZE_HIGH_BIT: Layout = unsafe { Layout::from_size_align_unchecked(SIZE_MAX + 1, 1) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .size: encountered 2147483648, but expected something less or equal to 2147483647
    |
    = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.

src/test/ui/consts/std/alloc.64bit.stderr

@@ -34,7 +34,7 @@ LL | const LAYOUT_SIZE_NEGATIVE_ONE: Layout = unsafe { Layout::from_size_align_u
 error[E0080]: it is undefined behavior to use this value
   --> $DIR/alloc.rs:21:1
    |
-LL | const LAYOUT_SIZE_HIGH_BIT: Layout = unsafe { Layout::from_size_align_unchecked((isize::MAX as usize) + 1, 1) };
+LL | const LAYOUT_SIZE_HIGH_BIT: Layout = unsafe { Layout::from_size_align_unchecked(SIZE_MAX + 1, 1) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .size: encountered 9223372036854775808, but expected something less or equal to 9223372036854775807
    |
    = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.

src/test/ui/consts/std/alloc.rs

@@ -18,7 +18,9 @@ const LAYOUT_SIZE_NEGATIVE_ONE: Layout = unsafe { Layout::from_size_align_unchec
 //~^ ERROR it is undefined behavior to use this value
 
 // not ok, since size needs to be no more than `isize::MAX`
-const LAYOUT_SIZE_HIGH_BIT: Layout = unsafe { Layout::from_size_align_unchecked((isize::MAX as usize) + 1, 1) };
+const LAYOUT_SIZE_HIGH_BIT: Layout = unsafe { Layout::from_size_align_unchecked(SIZE_MAX + 1, 1) };
 //~^ ERROR it is undefined behavior to use this value
 
+const SIZE_MAX: usize = isize::MAX as usize;
+
 fn main() {}