Merging upstream version 1.75.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 23 insertions, 0 deletions

diff --git a/tests/ui/lint/unaligned_references.rs b/tests/ui/lint/unaligned_references.rs
index 0c9c79c08..3f6dab354 100644
--- a/tests/ui/lint/unaligned_references.rs
+++ b/tests/ui/lint/unaligned_references.rs
@@ -1,3 +1,6 @@
+use std::mem::ManuallyDrop;
+use std::fmt::Debug;
+
 #[repr(packed)]
 pub struct Good {
     data: u64,
@@ -27,6 +30,26 @@ impl Foo for Packed2 {
     }
 }
 
+// Test for #115396
+fn packed_dyn() {
+    #[repr(packed)]
+    struct Unaligned<T: ?Sized>(ManuallyDrop<T>);
+
+    let ref local = Unaligned(ManuallyDrop::new([3, 5, 8u64]));
+    let foo: &Unaligned<dyn Debug> = &*local;
+    println!("{:?}", &*foo.0); //~ ERROR reference to packed field
+    let foo: &Unaligned<[u64]> = &*local;
+    println!("{:?}", &*foo.0); //~ ERROR reference to packed field
+
+    // Even if the actual alignment is 1, we cannot know that when looking at `dyn Debug.`
+    let ref local = Unaligned(ManuallyDrop::new([3, 5, 8u8]));
+    let foo: &Unaligned<dyn Debug> = &*local;
+    println!("{:?}", &*foo.0); //~ ERROR reference to packed field
+    // However, we *can* know the alignment when looking at a slice.
+    let foo: &Unaligned<[u8]> = &*local;
+    println!("{:?}", &*foo.0); // no error!
+}
+
 fn main() {
     unsafe {
         let good = Good { data: 0, ptr: &0, data2: [0, 0], aligned: [0; 32] };