t040bug80.g revision 324c4644fee44b9898524c09511bd33c3f12e2df 
1lexer grammar t040bug80; 
2options {
3  language = JavaScript;
4}
5 
6ID_LIKE
7    : 'defined' 
8    | {false}? Identifier 
9    | Identifier 
10    ; 
11 
12fragment 
13Identifier: 'a'..'z'+ ; // with just 'a', output compiles 
14