[antlr-interest] [BUG] 3.0b4 no complaint on parser reference to lexical fragment

[John B. Brodie]

Sorry if this is a duplicate.

This incorrect grammar draws no error report from org.antlr.Tool

grammar t;

@members {
   private static final String [] x = new String[]{
       "b", // no syntax error
       "c"  // draws syntax error
   };
   public static void main(String[] args) {
      for (int i=0; i < x.length; ++i) {
         try {
            tLexer lexer = new tLexer(new ANTLRStringStream(x[i]));
            CommonTokenStream tokens = new CommonTokenStream(lexer);
            t parser = new t(tokens);
            parser.startRule();
         } catch(Exception e) {
            e.printStackTrace();
         }
      }
   }
}

startRule : a EOF;
a : B | C ; // reference to a fragment, C
B : 'b' ;
fragment C : 'c' ; // not visible to parser