1 files changed, 117 insertions, 0 deletions
diff --git a/src/test/ui/transmutability/enums/repr/should_require_well_defined_layout.rs b/src/test/ui/transmutability/enums/repr/should_require_well_defined_layout.rs
new file mode 100644
index 000000000..978a12648
--- /dev/null
+++ b/src/test/ui/transmutability/enums/repr/should_require_well_defined_layout.rs
@@ -0,0 +1,117 @@
+//! An enum must have a well-defined layout to participate in a transmutation.
+
+#![crate_type = "lib"]
+#![feature(repr128)]
+#![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 void() {
+        enum repr_rust {}
+        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() {
+        enum repr_rust { V }
+        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() {
+        enum repr_rust { A, B }
+        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_primitive_reprs()
+{
+    fn should_accept_repr_i8() {
+        #[repr(i8)] enum repr_i8 { V }
+        assert::is_maybe_transmutable::<repr_i8, ()>();
+        assert::is_maybe_transmutable::<i8, repr_i8>();
+    }
+
+    fn should_accept_repr_u8() {
+        #[repr(u8)] enum repr_u8 { V }
+        assert::is_maybe_transmutable::<repr_u8, ()>();
+        assert::is_maybe_transmutable::<u8, repr_u8>();
+    }
+
+    fn should_accept_repr_i16() {
+        #[repr(i16)] enum repr_i16 { V }
+        assert::is_maybe_transmutable::<repr_i16, ()>();
+        assert::is_maybe_transmutable::<i16, repr_i16>();
+    }
+
+    fn should_accept_repr_u16() {
+        #[repr(u16)] enum repr_u16 { V }
+        assert::is_maybe_transmutable::<repr_u16, ()>();
+        assert::is_maybe_transmutable::<u16, repr_u16>();
+    }
+
+    fn should_accept_repr_i32() {
+        #[repr(i32)] enum repr_i32 { V }
+        assert::is_maybe_transmutable::<repr_i32, ()>();
+        assert::is_maybe_transmutable::<i32, repr_i32>();
+    }
+
+    fn should_accept_repr_u32() {
+        #[repr(u32)] enum repr_u32 { V }
+        assert::is_maybe_transmutable::<repr_u32, ()>();
+        assert::is_maybe_transmutable::<u32, repr_u32>();
+    }
+
+    fn should_accept_repr_i64() {
+        #[repr(i64)] enum repr_i64 { V }
+        assert::is_maybe_transmutable::<repr_i64, ()>();
+        assert::is_maybe_transmutable::<i64, repr_i64>();
+    }
+
+    fn should_accept_repr_u64() {
+        #[repr(u64)] enum repr_u64 { V }
+        assert::is_maybe_transmutable::<repr_u64, ()>();
+        assert::is_maybe_transmutable::<u64, repr_u64>();
+    }
+
+    fn should_accept_repr_i128() {
+        #[repr(i128)] enum repr_i128 { V }
+        assert::is_maybe_transmutable::<repr_i128, ()>();
+        assert::is_maybe_transmutable::<i128, repr_i128>();
+    }
+
+    fn should_accept_repr_u128() {
+        #[repr(u128)] enum repr_u128 { V }
+        assert::is_maybe_transmutable::<repr_u128, ()>();
+        assert::is_maybe_transmutable::<u128, repr_u128>();
+    }
+
+    fn should_accept_repr_isize() {
+        #[repr(isize)] enum repr_isize { V }
+        assert::is_maybe_transmutable::<repr_isize, ()>();
+        assert::is_maybe_transmutable::<isize, repr_isize>();
+    }
+
+    fn should_accept_repr_usize() {
+        #[repr(usize)] enum repr_usize { V }
+        assert::is_maybe_transmutable::<repr_usize, ()>();
+        assert::is_maybe_transmutable::<usize, repr_usize>();
+    }
+}
+
+fn should_accept_repr_C() {
+    #[repr(C)] enum repr_c { V }
+    assert::is_maybe_transmutable::<repr_c, ()>();
+    assert::is_maybe_transmutable::<i128, repr_c>();
+}