CALLER_BINDING_CLASS 1112 vm_backtrace.c     rb_ary_store(frame, CALLER_BINDING_CLASS, get_klass(cfp));
CALLER_BINDING_CLASS 1127 vm_backtrace.c     rb_ary_store(frame, CALLER_BINDING_CLASS, get_klass(cfp));
CALLER_BINDING_CLASS 1220 vm_backtrace.c     return rb_ary_entry(frame, CALLER_BINDING_CLASS);