[perl #125996] Complex parametric role composition fails badly when no candidate found

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This code::

  role R[$a,$b] {}
  role R2[$x] does R[1] {}
  class C does R2[1] {}

  C.new;

Produces the error message::

  ===SORRY!===
  Cannot find method 'collisions'

The error happens in ``RoleToClassApplier::apply``: something goes
wrong with the nested role specialisation, and the compiler tries to
apply a ``NQPMu``.

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        Dakkar - <Mobilis in mobile>
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Giving up on assembly language was the apple in our Garden of Eden:
Languages whose use squanders machine cycles are sinful.  The LISP
machine now permits LISP programmers to abandon bra and fig-leaf.
                -- Epigrams in Programming, ACM SIGPLAN Sept. 1982