[antlr-interest] Possible Antlr defect?

[Stuart Dootson]

I've found what appears to be a bug when using separate grammars -
Antlr doesn't appear to give a warning or (preferably) error when
using an undefined token type. I had the following token types:

WS=6
IDENTIFIER=4
NUMERIC_LITERAL=5
SL_COMMENT=7
'='=9
';'=8

and the following parser grammar was processed by Antlr without
warning or error:

parser grammar TestP;

options
{
   tokenVocab = Test;
   output=AST;
   language = C;
}

grammarMain
   :  (statement ';'!) +
   ;

statement
   :  ID '=' value -> ^('=' IDENTIFIER value)
   ;

value
   :  IDENTIFIER
   |  NUMERIC_LITERAL
   ;

You'll note the 'statement' rule uses 'ID' rather than 'IDENTIFIER' -
I would expect Antlr to complain about that...but it doesn't (BTW -
it's the 3.0 release, on OS X 10.4.9).

I can't really believe I'm the first person to see this - but I didn't
see any mention in mailing list or bug list...

Stuart Dootson