1 files changed, 51 insertions, 0 deletions
diff --git a/tests/ui/structs-enums/enum-univariant-repr.rs b/tests/ui/structs-enums/enum-univariant-repr.rs
new file mode 100644
index 00000000000..1e0f6788778
--- /dev/null
+++ b/tests/ui/structs-enums/enum-univariant-repr.rs
@@ -0,0 +1,51 @@
+// run-pass
+
+use std::mem;
+
+// Univariant C-like enum
+#[repr(i32)]
+enum Univariant {
+    X = 17
+}
+
+#[repr(u16)]
+enum UnivariantWithoutDescr {
+    Y
+}
+
+#[repr(u8)]
+enum UnivariantWithData {
+    Z(u8),
+}
+
+pub fn main() {
+    {
+        assert_eq!(4, mem::size_of::<Univariant>());
+        assert_eq!(17, Univariant::X as i32);
+
+        let enums: &[Univariant] =
+            &[Univariant::X, Univariant::X, Univariant::X];
+        let ints: &[i32] = unsafe { mem::transmute(enums) };
+        // check it has the same memory layout as i32
+        assert_eq!(&[17, 17, 17], ints);
+    }
+
+    {
+        assert_eq!(2, mem::size_of::<UnivariantWithoutDescr>());
+        let descr = UnivariantWithoutDescr::Y as u16;
+
+        let enums: &[UnivariantWithoutDescr] =
+            &[UnivariantWithoutDescr::Y, UnivariantWithoutDescr::Y, UnivariantWithoutDescr::Y];
+        let ints: &[u16] = unsafe { mem::transmute(enums) };
+        // check it has the same memory layout as u16
+        assert_eq!(&[descr, descr, descr], ints);
+    }
+
+    {
+        assert_eq!(2, mem::size_of::<UnivariantWithData>());
+
+        match UnivariantWithData::Z(4) {
+            UnivariantWithData::Z(x) => assert_eq!(x, 4),
+        }
+    }
+}