Rollup merge of #104632 - RalfJung:core-test-strict-provenance, r=thomcc

avoid non-strict-provenance casts in libcore tests

r? `@thomcc`

library/core/src/lib.rs

@@ -89,6 +89,7 @@
 // Lints:
 #![deny(rust_2021_incompatible_or_patterns)]
 #![deny(unsafe_op_in_unsafe_fn)]
+#![deny(fuzzy_provenance_casts)]
 #![warn(deprecated_in_future)]
 #![warn(missing_debug_implementations)]
 #![warn(missing_docs)]
@@ -162,6 +163,7 @@
 #![feature(slice_ptr_get)]
 #![feature(slice_split_at_unchecked)]
 #![feature(str_internals)]
+#![feature(strict_provenance)]
 #![feature(utf16_extra)]
 #![feature(utf16_extra_const)]
 #![feature(variant_count)]

library/core/src/ptr/const_ptr.rs

@@ -140,6 +140,7 @@ impl<T: ?Sized> *const T {
     /// assert_eq!(<*const u8>::from_bits(1), dangling);
     /// ```
     #[unstable(feature = "ptr_to_from_bits", issue = "91126")]
+    #[allow(fuzzy_provenance_casts)] // this is an unstable and semi-deprecated cast function
     pub fn from_bits(bits: usize) -> Self
     where
         T: Sized,

library/core/src/ptr/mod.rs

@@ -616,6 +616,7 @@ pub const fn invalid_mut<T>(addr: usize) -> *mut T {
 #[inline]
 #[unstable(feature = "strict_provenance", issue = "95228")]
 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
+#[allow(fuzzy_provenance_casts)] // this *is* the strict provenance API one should use instead
 pub fn from_exposed_addr<T>(addr: usize) -> *const T
 where
     T: Sized,
@@ -653,6 +654,7 @@ where
 #[inline]
 #[unstable(feature = "strict_provenance", issue = "95228")]
 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
+#[allow(fuzzy_provenance_casts)] // this *is* the strict provenance API one should use instead
 pub fn from_exposed_addr_mut<T>(addr: usize) -> *mut T
 where
     T: Sized,

library/core/src/ptr/mut_ptr.rs

@@ -146,6 +146,7 @@ impl<T: ?Sized> *mut T {
     /// assert_eq!(<*mut u8>::from_bits(1), dangling);
     /// ```
     #[unstable(feature = "ptr_to_from_bits", issue = "91126")]
+    #[allow(fuzzy_provenance_casts)] // this is an unstable and semi-deprecated cast function
     pub fn from_bits(bits: usize) -> Self
     where
         T: Sized,

library/core/tests/lib.rs

@@ -109,6 +109,7 @@
 #![feature(utf8_chunks)]
 #![feature(is_ascii_octdigit)]
 #![deny(unsafe_op_in_unsafe_fn)]
+#![deny(fuzzy_provenance_casts)]
 
 extern crate test;
 

library/core/tests/ptr.rs

@@ -677,7 +677,7 @@ fn align_offset_issue_103361() {
     #[cfg(target_pointer_width = "16")]
     const SIZE: usize = 1 << 13;
     struct HugeSize([u8; SIZE - 1]);
-    let _ = (SIZE as *const HugeSize).align_offset(SIZE);
+    let _ = ptr::invalid::<HugeSize>(SIZE).align_offset(SIZE);
 }
 
 #[test]