Add test for discriminant_value results

Author: Aatch

src/test/run-pass/discriminant_value.rs

@@ -0,0 +1,62 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+extern crate core;
+use core::intrinsics::discriminant_value;
+
+enum CLike1 {
+    A,
+    B,
+    C,
+    D
+}
+
+enum CLike2 {
+    A = 5,
+    B = 2,
+    C = 19,
+    D
+}
+
+enum ADT {
+    First(u32, u32),
+    Second(u64)
+}
+
+enum NullablePointer {
+    Something(&'static u32),
+    Nothing
+}
+
+static CONST : u32 = 0xBEEF;
+
+pub fn main() {
+    unsafe {
+
+        assert_eq!(discriminant_value(&CLike1::A), 0);
+        assert_eq!(discriminant_value(&CLike1::B), 1);
+        assert_eq!(discriminant_value(&CLike1::C), 2);
+        assert_eq!(discriminant_value(&CLike1::D), 3);
+
+        assert_eq!(discriminant_value(&CLike2::A), 5);
+        assert_eq!(discriminant_value(&CLike2::B), 2);
+        assert_eq!(discriminant_value(&CLike2::C), 19);
+        assert_eq!(discriminant_value(&CLike2::D), 20);
+
+        assert_eq!(discriminant_value(&ADT::First(0,0)), 0);
+        assert_eq!(discriminant_value(&ADT::Second(5)), 1);
+
+        assert_eq!(discriminant_value(&NullablePointer::Nothing), 1);
+        assert_eq!(discriminant_value(&NullablePointer::Something(&CONST)), 0);
+
+        assert_eq!(discriminant_value(&10), 0);
+        assert_eq!(discriminant_value(&"test"), 0);
+    }
+}