diff --git a/rollup.config.js b/rollup.config.js
index 48f90651b9..e0a719a62e 100644
--- a/rollup.config.js
+++ b/rollup.config.js
@@ -128,7 +128,7 @@ const config = {
 
     // Custom warning handler to give more information about circular dependencies
     onwarn: function(warning,warn) {
-        console.warn(warning.message || warning);
+        console.warn(warning.toString());
     }
 };