[antlr-interest] Help! Predicate failed messages

[chain one]

I noticed the first time parse is OK.But when turning isFirst to false, this
kind of error message keep coming out.
I don't know why the  failure of a predicate would lead to an error.

2008/12/3 chain one <chainone at gmail.com>

> And there are a lot of  error tag in the final printed tree like this:
>  (TYPE_DECL <error: temperature>
>
> Is it caused by the failure of the predicate?
>
>
> 2008/12/3 chain one <chainone at gmail.com>
>
> procedure_id
>>      : { isFirst }? id=IDENT { addId($id.getText(),PROCEDURE_IDENT); }
>>              |  nid=PROCEDURE_IDENT { $nid.setType(IDENT);} ->
>> ^(PROCEDURE_ID[] PROCEDURE_IDENT)
>>              ;
>> In the first pass, isFirst  is true, and in the second pass, isFirst is
>> set to be false.
>> When running the generated Java code, it seems every time
>> the predicate fails, there will be an error message coming out like this:
>>
>> line 43:41 rule named_types failed predicate: { isFirst }?
>>
>> Could it be ignored? or there is something wrong with my grammar file?
>>
>>
>
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