Merging upstream version 1.68.2+dfsg1.

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

1 files changed, 44 insertions, 0 deletions

diff --git a/tests/ui/transmutability/unions/repr/should_require_well_defined_layout.rs b/tests/ui/transmutability/unions/repr/should_require_well_defined_layout.rs
new file mode 100644
index 000000000..b1d5f71dc
--- /dev/null
+++ b/tests/ui/transmutability/unions/repr/should_require_well_defined_layout.rs
@@ -0,0 +1,44 @@
+//! A struct must have a well-defined layout to participate in a transmutation.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code, incomplete_features, non_camel_case_types)]
+
+mod assert {
+    use std::mem::{Assume, BikeshedIntrinsicFrom};
+    pub struct Context;
+
+    pub fn is_maybe_transmutable<Src, Dst>()
+    where
+        Dst: BikeshedIntrinsicFrom<Src, Context, {
+            Assume {
+                alignment: true,
+                lifetimes: true,
+                safety: true,
+                validity: true,
+            }
+        }>
+    {}
+}
+
+fn should_reject_repr_rust()
+{
+    union repr_rust {
+        a: u8
+    }
+
+    assert::is_maybe_transmutable::<repr_rust, ()>(); //~ ERROR cannot be safely transmuted
+    assert::is_maybe_transmutable::<u128, repr_rust>(); //~ ERROR cannot be safely transmuted
+}
+
+fn should_accept_repr_C()
+{
+    #[repr(C)]
+    union repr_c {
+        a: u8
+    }
+
+    struct repr_rust;
+    assert::is_maybe_transmutable::<repr_c, ()>();
+    assert::is_maybe_transmutable::<u128, repr_c>();
+}