diff --git a/src/libstore/path.hh b/src/libstore/path.hh
index 6b29c3566..c31ea2179 100644
--- a/src/libstore/path.hh
+++ b/src/libstore/path.hh
@@ -7,7 +7,7 @@ namespace nix {
 /* See path.rs. */
 struct StorePath;
 
-struct Store;
+class Store;
 
 extern "C" {
     void ffi_StorePath_drop(void *);