1 files changed, 61 insertions, 0 deletions
diff --git a/src/test/ui/transmutability/arrays/should_require_well_defined_layout.rs b/src/test/ui/transmutability/arrays/should_require_well_defined_layout.rs
new file mode 100644
index 000000000..8e69527c1
--- /dev/null
+++ b/src/test/ui/transmutability/arrays/should_require_well_defined_layout.rs
@@ -0,0 +1,61 @@
+//! An array 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::BikeshedIntrinsicFrom;
+    pub struct Context;
+
+    pub fn is_maybe_transmutable<Src, Dst>()
+    where
+        Dst: BikeshedIntrinsicFrom<Src, Context, true, true, true, true>
+    {}
+}
+
+fn should_reject_repr_rust()
+{
+    fn unit() {
+        type repr_rust = [String; 0];
+        assert::is_maybe_transmutable::<repr_rust, ()>(); //~ ERROR cannot be safely transmuted
+        assert::is_maybe_transmutable::<u128, repr_rust>(); //~ ERROR cannot be safely transmuted
+    }
+
+    fn singleton() {
+        type repr_rust = [String; 1];
+        assert::is_maybe_transmutable::<repr_rust, ()>(); //~ ERROR cannot be safely transmuted
+        assert::is_maybe_transmutable::<u128, repr_rust>(); //~ ERROR cannot be safely transmuted
+    }
+
+    fn duplex() {
+        type repr_rust = [String; 2];
+        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()
+{
+    fn unit() {
+        #[repr(C)] struct repr_c(u8, u16, u8);
+        type array = [repr_c; 0];
+        assert::is_maybe_transmutable::<array, ()>();
+        assert::is_maybe_transmutable::<i128, array>();
+    }
+
+    fn singleton() {
+        #[repr(C)] struct repr_c(u8, u16, u8);
+        type array = [repr_c; 1];
+        assert::is_maybe_transmutable::<array, repr_c>();
+        assert::is_maybe_transmutable::<repr_c, array>();
+    }
+
+    fn duplex() {
+        #[repr(C)] struct repr_c(u8, u16, u8);
+        #[repr(C)] struct duplex(repr_c, repr_c);
+        type array = [repr_c; 2];
+        assert::is_maybe_transmutable::<array, duplex>();
+        assert::is_maybe_transmutable::<duplex, array>();
+    }
+}