Add tests ensuring mutable refs are not Copy/Clone

Author: nathanwhit

tests/test/refs.rs

@@ -30,7 +30,7 @@ fn refs_are_sized() {
 }
 
 #[test]
-fn refs_are_copy() {
+fn immut_refs_are_copy() {
     test! {
         program {
             #[lang(copy)]
@@ -46,7 +46,7 @@ fn refs_are_copy() {
 }
 
 #[test]
-fn refs_are_clone() {
+fn immut_refs_are_clone() {
     test! {
         program {
             #[lang(clone)]
@@ -60,3 +60,35 @@ fn refs_are_clone() {
         }
     }
 }
+
+#[test]
+fn mut_refs_are_not_copy() {
+    test! {
+        program {
+            #[lang(copy)]
+            trait Copy { }
+        }
+
+        goal {
+            forall<'a, T> { not { &'a mut T: Copy } }
+        } yields {
+            "Unique; substitution [], lifetime constraints []"
+        }
+    }
+}
+
+#[test]
+fn mut_refs_are_not_clone() {
+    test! {
+        program {
+            #[lang(clone)]
+            trait Clone { }
+        }
+
+        goal {
+            forall<'a, T> { not { &'a mut T: Clone } }
+        } yields {
+            "Unique; substitution [], lifetime constraints []"
+        }
+    }
+}