emit error message when compiling a reference to a closed variable
emit error message when compiling a reference to a closed variable

picrin-scheme/picrin,dcurrie/picrin,koba-e964/picrin,leavesbnw/picrin,koba-e964/picrin,ktakashi/picrin,koba-e964/picrin,dcurrie/picrin,omasanori/picrin,ktakashi/picrin,ktakashi/picrin,picrin-scheme/picrin,leavesbnw/picrin,omasanori/picrin,leavesbnw/picrin