diff --git a/source/dub/dub.d b/source/dub/dub.d
index d91fb46..1eeea9c 100644
--- a/source/dub/dub.d
+++ b/source/dub/dub.d
@@ -1914,7 +1914,7 @@
 		return p;
 	}
 
-	private Package getPackageRaw(PackageName name, Dependency dep)
+	private Package getPackageRaw(in PackageName name, Dependency dep)
 	{
 		import dub.recipe.json;