do not assume callee.caller always exists

1 files changed, 2 insertions, 1 deletions

diff --git a/src/library.js b/src/library.js
index fc731e01..354e5549 100644
--- a/src/library.js
+++ b/src/library.js
@@ -8858,7 +8858,8 @@ LibraryManager.library = {
       }
     }
     str += ')';
-    args = args.callee.caller.arguments;
+    var caller = args.callee.caller;
+    args = caller ? caller.arguments : [];
     if (first)
       str = '';
     return [args, funcname, str];