rb_ivar_lookup 1335 error.c recv = rb_ivar_lookup(self, id_receiver, Qundef); rb_ivar_lookup 1446 internal.h VALUE rb_ivar_lookup(VALUE obj, ID id, VALUE undef); rb_ivar_lookup 1259 variable.c VALUE iv = rb_ivar_lookup(obj, id, Qundef); rb_ivar_lookup 1272 variable.c return rb_ivar_lookup(obj, id, Qnil);