[perl #68138] Rakudo tries to call role-parameter typename as a sub when using 'does' with a parameterized RHS && missing line# in the error

[Christian Bartolomaeus via RT]

There was already a (skipped) test in S14-roles/parameterized-type.t. I 
adjusted the test to use '@!children handles <at_pos assign_pos bind_pos>' as 
Mouq++ pointed out: 
https://github.com/perl6/roast/commit/223db17d80

I'm closing this ticket as 'resolved'.