Cover scoped panic restoration

src/tests.rs

@@ -892,6 +892,38 @@ fn test_scoped_guard_reserve_restore_and_take() {
     assert_eq!(erased.capacity(), 0);
 }
 
+#[test]
+fn test_scoped_guard_restores_after_panic_and_clears_stale_bytes() {
+    let mut erased = TypeErasedVec::new(Vec::<&'static str>::with_capacity(4));
+    let (retained_ptr, retained_capacity);
+
+    {
+        let first = String::from("first");
+        let second = String::from("second");
+        let mut guard = erased.as_type_scoped::<&str>();
+        retained_ptr = guard.as_slice().as_ptr();
+        retained_capacity = guard.capacity();
+
+        let result = panic::catch_unwind(panic::AssertUnwindSafe(|| {
+            guard.with(|values| {
+                values.push(&first);
+                values.push(&second);
+                panic!("stop after scoped mutations");
+            });
+        }));
+
+        assert!(result.is_err());
+        assert_eq!(guard.as_slice(), &["first", "second"]);
+        assert_eq!(guard.as_slice().as_ptr(), retained_ptr);
+        assert_eq!(guard.capacity(), retained_capacity);
+    }
+
+    assert_eq!(erased.length(), 2);
+    erased.clear();
+    assert!(erased.is_empty());
+    assert_eq!(erased.capacity(), retained_capacity);
+}
+
 #[test]
 fn test_unchecked_methods() {
     let vec = vec![123_u32];