test for validity of references pointing to uninhabited types

tests/compile-fail/validity/ref_to_uninhabited1.rs

@@ -0,0 +1,6 @@
+#![feature(never_type)]
+use std::mem::transmute;
+
+fn main() { unsafe {
+    let _x: &! = transmute(&42); //~ERROR encountered a reference pointing to uninhabited type !
+} }

tests/compile-fail/validity/ref_to_uninhabited2.rs

@@ -0,0 +1,7 @@
+use std::mem::transmute;
+
+enum Void {}
+
+fn main() { unsafe {
+    let _x: &(i32, Void) = transmute(&42); //~ERROR encountered a reference pointing to uninhabited type (i32, Void)
+} }