Generator to ... is not an argument, but a value in the list

It doesn't even have to be a literal.

    > my $lhs = (5, { $_ * 2 });
    > say $lhs ... 40;
    (5 10 20 40)

Author: Juerd

doc/Language/operators.pod6

@@ -2275,7 +2275,7 @@ with a default generator of *.succ
 
     say (1 ... *)[^5];  # OUTPUT: «(1 2 3 4 5)␤»
 
-Custom generators need to be the last argument before the '...' operator.
+Custom generators need to be the last element of the list before the '...' operator.
 This one takes two arguments, and generates the Fibonacci numbers
 
     say (1, 1, -> $a, $b { $a + $b } ... *)[^8];    # OUTPUT: «(1 1 2 3 5 8 13 21)␤»