grammar GreedyTest;
//options
//{
	// backtrack = true;
//}

start
// options { backtrack = true; }
    : rule EOF;

rule 
// options { backtrack = true; }
	: ( options{ greedy=false;} : any )+ some 
    ;

any
// options { backtrack = true; }
	: A 
	| B 
	| C 
	| D 
	;

some
// options { backtrack = true; }
	// : A // this works fine.
	: A B // this does not. why? the lookaheadset is the same: {A,B}. 
	| B
	;

A: 'A';
B: 'B';
C: 'C';
D: 'D';