cyclical rule problem

rule_prob.p6

#!/usr/bin/env perl6

use v6;

grammar Problem {
	token TOP { <expression> }

	rule expression { <operation> | <value> }
	rule operation {<expression> <operator> <expression>}
	token operator { \+ | \- | \* | \/ }
	token value { \d+ }
}

grammar NoProblem is Problem {
	# the only difference here is that the rules have been changed to tokens
	token expression { <operation> | <value> }
	token operation {<expression> <operator> <expression>}
}

NoProblem.parse("1").perl.say; # expected result
Problem.parse("1").perl.say; # infinite loop