1 files changed, 41 insertions, 0 deletions
diff --git a/src/test/ui/transmutability/unions/repr/should_handle_packed.rs b/src/test/ui/transmutability/unions/repr/should_handle_packed.rs
new file mode 100644
index 000000000..34a53c7a8
--- /dev/null
+++ b/src/test/ui/transmutability/unions/repr/should_handle_packed.rs
@@ -0,0 +1,41 @@
+// check-pass
+//! The presence of an `align(X)` annotation must be accounted for.
+
+#![crate_type = "lib"]
+#![feature(transmutability)]
+#![allow(dead_code, incomplete_features, non_camel_case_types)]
+
+mod assert {
+    use std::mem::BikeshedIntrinsicFrom;
+    pub struct Context;
+
+    pub fn is_maybe_transmutable<Src, Dst>()
+    where
+        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+    {}
+}
+
+fn should_pad_explicitly_packed_field() {
+    #[derive(Clone, Copy)] #[repr(u8)] enum V0u8 { V = 0 }
+    #[derive(Clone, Copy)] #[repr(u8)] enum V1u8 { V = 1 }
+    #[derive(Clone, Copy)] #[repr(u8)] enum V2u8 { V = 2 }
+    #[derive(Clone, Copy)] #[repr(u32)] enum V3u32 { V = 3 }
+
+    #[repr(C)]
+    pub union Uninit {
+        a: (),
+        b: V1u8,
+    }
+
+    #[repr(C, packed(2))]
+    pub union Packed {
+        a: [V3u32; 0],
+        b: V0u8,
+    }
+
+    #[repr(C)] struct ImplicitlyPadded(Packed, V2u8);
+    #[repr(C)] struct ExplicitlyPadded(V0u8, Uninit, V2u8);
+
+    assert::is_maybe_transmutable::<ImplicitlyPadded, ExplicitlyPadded>();
+    assert::is_maybe_transmutable::<ExplicitlyPadded, ImplicitlyPadded>();
+}