diff --git a/src/libfetchers/include/nix/fetchers/input-cache.hh b/src/libfetchers/include/nix/fetchers/input-cache.hh
index a7ca34487..869c7d41e 100644
--- a/src/libfetchers/include/nix/fetchers/input-cache.hh
+++ b/src/libfetchers/include/nix/fetchers/input-cache.hh
@@ -26,6 +26,8 @@ struct InputCache
     virtual void clear() = 0;
 
     static ref<InputCache> create();
+
+    virtual ~InputCache() = default;
 };
 
 }