Rollup merge of #103729 - RalfJung:align-of-val-packed, r=oli-obk

interpret: fix align_of_val on packed types

Fixes rust-lang/miri#2632

r? `@oli-obk`

Author: Dylan-DPC

core/tests/lib.rs

@@ -5,6 +5,7 @@
 #![feature(bigint_helper_methods)]
 #![feature(cell_update)]
 #![feature(const_assume)]
+#![feature(const_align_of_val_raw)]
 #![feature(const_black_box)]
 #![feature(const_bool_to_option)]
 #![feature(const_caller_location)]
@@ -42,6 +43,7 @@
 #![feature(try_find)]
 #![feature(inline_const)]
 #![feature(is_sorted)]
+#![feature(layout_for_ptr)]
 #![feature(pattern)]
 #![feature(pin_macro)]
 #![feature(sort_internals)]

core/tests/mem.rs

@@ -1,4 +1,5 @@
 use core::mem::*;
+use core::ptr;
 
 #[cfg(panic = "unwind")]
 use std::rc::Rc;
@@ -75,6 +76,25 @@ fn align_of_val_basic() {
     assert_eq!(align_of_val(&1u32), 4);
 }
 
+#[test]
+#[cfg(not(bootstrap))] // stage 0 doesn't have the fix yet, so the test fails
+fn align_of_val_raw_packed() {
+    #[repr(C, packed)]
+    struct B {
+        f: [u32],
+    }
+    let storage = [0u8; 4];
+    let b: *const B = ptr::from_raw_parts(storage.as_ptr().cast(), 1);
+    assert_eq!(unsafe { align_of_val_raw(b) }, 1);
+
+    const ALIGN_OF_VAL_RAW: usize = {
+        let storage = [0u8; 4];
+        let b: *const B = ptr::from_raw_parts(storage.as_ptr().cast(), 1);
+        unsafe { align_of_val_raw(b) }
+    };
+    assert_eq!(ALIGN_OF_VAL_RAW, 1);
+}
+
 #[test]
 fn test_swap() {
     let mut x = 31337;