Found it: The line

 my $client_export_def= bless find_export_def ($caller, $param_list_ta
+il), "Exporter::VA";
[download]

was passing @_ instead of $param_list_tail to the find_export_def function. So it never found and removed it in the first place, and the error came later on as tye points out.

That's what testing is for, especially in a language that doesn't find much at "compile time" like some others.