diff --git a/src/cipher.rs b/src/cipher.rs
index 1fc9e0b0..cfe72c75 100644
--- a/src/cipher.rs
+++ b/src/cipher.rs
@@ -532,9 +532,7 @@ impl rustls_root_cert_store_builder {
                 Some(b) => b,
             };
 
-            unsafe {
-                *root_cert_store_out = ArcCastPtr::to_const_ptr(builder.roots.clone());
-            }
+            ArcCastPtr::set_mut_ptr(root_cert_store_out, builder.roots.clone());
 
             rustls_result::Ok
         }
@@ -743,10 +741,7 @@ impl rustls_web_pki_client_cert_verifier_builder {
                 Err(e) => return error::map_verifier_builder_error(e),
             };
 
-            // TODO(XXX): Is there a safer way to handle this ala BoxCastPtr::set_mut_ptr?
-            unsafe {
-                *verifier_out = ArcCastPtr::to_const_ptr(verifier)
-            }
+            ArcCastPtr::set_mut_ptr(verifier_out, verifier);
 
             rustls_result::Ok
         }
diff --git a/src/lib.rs b/src/lib.rs
index b64f446a..2c31dd10 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -399,6 +399,12 @@ pub(crate) trait ArcCastPtr: CastConstPtr + Sized {
     fn to_const_ptr(src: Self::RustType) -> *const Self {
         Arc::into_raw(Arc::new(src)) as *const _
     }
+
+    fn set_mut_ptr(dst: *mut *const Self, src: Self::RustType) {
+        unsafe {
+            *dst = Self::to_const_ptr(src);
+        }
+    }
 }
 
 #[doc(hidden)]