[antlr-interest] Is it a BUG in the Lexer-Rule-Checker?

[T.Lindig]

Hi,

don't know, if this is the right place for bug reports, but i can't 
found a better one.

I working with ANTLR 2.7.4

the folowing Lexer-Grammer brings a "lexical nondeterminism" warning.

 >>>>>>>>>> begin <<<<<<<<<<<<<<<<<
class COMALexer extends Lexer;

options {
   k=3;
}

PREPROCESSOR:
   "#test"
   (PREPRO_INLINE_WS)?   //here we get the warning
   (SL_COMMENT)?
;

protected
PREPRO_INLINE_WS :
   (
     INLINE_SPACE
   | ML_COMMENT
   )+
;

protected
INLINE_SPACE
   :   ' ' | '\t' | '\f'
   ;

// multiple-line comments
ML_COMMENT
   :
     "/*" ( options{greedy=false;} :  . )*
     "*/"
     { $setType(Token.SKIP); }
   ;

// Single-line comments
SL_COMMENT
   :  "//" ( ~('\n'|'\r'))*
   { $setType(Token.SKIP); }
;


// Whitespace -- ignored
WS:
   ( INLINE_SPACE )+
   { $setType(Token.SKIP); }
;

 >>>>>>>>>>>>>>>>>>>>>>> end <<<<<<<<<<<<<<<<<<<<<<


ANTLR Parser Generator   Version 2.7.4   1989-2004 jGuru.com
CommentTest.g:9:3: warning:lexical nondeterminism between alts 1 and 2 
of block upon
CommentTest.g:9:3:     k==1:'/'
CommentTest.g:9:3:     k==2:<end-of-token>,'/'
CommentTest.g:9:3:     k==3:<end-of-token>,'\t','\u000c',' 
','#','*','/','e','s','t'


but if i substitute the PREPRO_INLINE_WS token in the PREPROCESSOR rule 
like here:

PREPROCESSOR:
   "#test"
   ( INLINE_SPACE | ML_COMMENT )*
   (SL_COMMENT)?
;

I will get no warning. know also ANTLR see, that this code is correct.

so, is it a bug in ANTLR or did i looked over something?

Thanks for help,
Tobias