Not implemented yet because we just added it, but in Perl 6 you can just say:

.say for 1,1...{$^a+$^b}
[download]

or alternately:

.say for 1,1...&infix:<+>
[download]

The latter is likely to be more efficient, since it calls the builtin addition operator without the extra layer of function call implied by the first one (unless we get really fancy with the optimizer and notice it's an identity wrapper).

Either of these works because the ... operator is defined to pass the last N numbers in the list repeatedly to the generator function, where N is determined by the arity of the function, which is 2 in this case.