diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh
index bf85b50c8..e2180f00d 100644
--- a/src/libexpr/eval.hh
+++ b/src/libexpr/eval.hh
@@ -218,6 +218,11 @@ public:
 
     Bindings emptyBindings;
 
+    /**
+     * Empty list constant.
+     */
+    Value vEmptyList;
+
     /**
      * The accessor for the root filesystem.
      */
@@ -305,9 +310,6 @@ public:
         return *errorBuilder;
     }
 
-    /* Empty list constant. */
-    Value vEmptyList;
-
 private:
 
     /* Cache for calls to addToStore(); maps source paths to the store