Fetch its bytecode before unfolding a compiled function, byte-optimize.el lisp/ChangeLog addition: 2012-05-12 Aidan Kehoe <kehoea@parhasard.net> * byte-optimize.el (byte-compile-unfold-lambda): Fetch the bytecode before unfolding a compiled function, its body may have been compiled lazily thanks to byte-compile-dynamic. Thank you Mats Lidell and the package smoketest!