DEFINED_IVAR     3436 compile.c      	ADD_INSN3(ret, nd_line(node), defined, INT2FIX(DEFINED_IVAR),
DEFINED_IVAR     2548 vm_insnhelper.c       case DEFINED_IVAR:
DEFINED_IVAR     2550 vm_insnhelper.c 	    expr_type = DEFINED_IVAR;