1 files changed, 43 insertions, 0 deletions
diff --git a/tests/ui/enum-discriminant/arbitrary_enum_discriminant.rs b/tests/ui/enum-discriminant/arbitrary_enum_discriminant.rs
new file mode 100644
index 00000000000..83e74a6e685
--- /dev/null
+++ b/tests/ui/enum-discriminant/arbitrary_enum_discriminant.rs
@@ -0,0 +1,43 @@
+// run-pass
+#![feature(test)]
+
+extern crate test;
+
+use test::black_box;
+
+#[allow(dead_code)]
+#[repr(u8)]
+enum Enum {
+    Unit = 3,
+    Tuple(u16) = 2,
+    Struct {
+        a: u8,
+        b: u16,
+    } = 1,
+}
+
+impl Enum {
+    const unsafe fn tag(&self) -> u8 {
+        *(self as *const Self as *const u8)
+    }
+}
+
+fn main() {
+    const UNIT: Enum = Enum::Unit;
+    const TUPLE: Enum = Enum::Tuple(5);
+    const STRUCT: Enum = Enum::Struct{a: 7, b: 11};
+
+    // Ensure discriminants are correct during runtime execution
+    assert_eq!(3, unsafe { black_box(UNIT).tag() });
+    assert_eq!(2, unsafe { black_box(TUPLE).tag() });
+    assert_eq!(1, unsafe { black_box(STRUCT).tag() });
+
+    // Ensure discriminants are correct during CTFE
+    const UNIT_TAG: u8 = unsafe { UNIT.tag() };
+    const TUPLE_TAG: u8 = unsafe { TUPLE.tag() };
+    const STRUCT_TAG: u8 = unsafe { STRUCT.tag() };
+
+    assert_eq!(3, UNIT_TAG);
+    assert_eq!(2, TUPLE_TAG);
+    assert_eq!(1, STRUCT_TAG);
+}