Add support for boxed values (#4)

expunge/src/lib.rs

@@ -72,7 +72,7 @@
 
 use std::{
     collections::{HashMap, HashSet},
-    ops::{Deref, DerefMut},
+    ops::{Deref, DerefMut}, sync::Arc,
 };
 
 pub use expunge_derive::*;
@@ -242,6 +242,14 @@ where
     }
 }
 
+impl<T> Expunge for Box<T> where T: Expunge {
+    fn expunge(self) -> Self
+    where
+        Self: Sized {
+            Box::new((*self).expunge())
+    }
+}
+
 #[cfg(feature = "zeroize")]
 impl<T> Expunge for Secret<T>
 where

expunge/tests/expunge.rs

@@ -284,3 +284,18 @@ fn it_works_enum() {
     let expunged = item.expunge();
     assert_eq!(SensitiveItem::ZeroizableString("99".to_string()), expunged);
 }
+
+#[test]
+fn it_returns_boxed() {
+    #[derive(Expunge)]
+    struct Location {
+        #[expunge]
+        city: String,
+    }
+
+    let location = Box::new(Location {
+        city: "New York".to_string(),
+    });
+
+    let _: Box<Location> = location.expunge();
+}