AndrewVos/rubinius — comment on commit e9a9b19ab14e6e3c1bf6541d29a98f911900ec3c
File: kernel/common/io19.rb line 366
By brixen:

I think this condition is wrong because #puts can receive multiple arguments (eg 'puts nil, nil, nil').

A better fix would be below on the 'if arg.equal? nil' condition.