[perl #118063] [BUG] comma (wrongly) required between parameter with default value and returns-arrow ('-->') in Rakudo

[Christian Bartolomaeus via RT]

This works now without the comma:

$ perl6-m -e 'sub a ( $a=1 --> Hash ) { say $a; my %h }; say a(2)'
2

^^ empty string here ;-)

I added a test to S06-signature/defaults.t with the following commit: 
https://github.com/perl6/roast/commit/4485db4547