diff --git a/rc.go b/rc.go
index a5588df..ae65f03 100644
--- a/rc.go
+++ b/rc.go
@@ -27,7 +27,7 @@ type Handler interface {
 	Storable(req *http.Request, res *http.Response, now time.Time) (ok bool, expires time.Time)
 }
 
-var _ Handler = new(rfc9111.Shared)
+var _ Handler = (*rfc9111.Shared)(nil)
 
 type cacher struct {
 	Cacher