[luatex] Fatal error with attr keyword to \hbox or \vbox

[Esger Renkema]

>> > Which format are you using ? plain ?
>>
>> Yes, plain. You should append a \bye to both examples, I guess.
>>
>> Of course, the problem disappears when using luaotfload, which must 
>> be why no one has run into this bug before.
>>
>>
>Also there is no problem with
>mtxrun --script plain

Yes, the luatex-plain format used by mtxrun loads extra code that sets 
\attribute0=0 somehow. I could not find where. No attributes are set by 
luatex.fmt, however.