[perl #127075] Error referencing non-ascii tokens on grammar

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# New Ticket Created by  Rúbio Terra 
# Please include the string:  [perl #127075]
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I can declare non-ascii tokens without problems on a grammar but I get an 
encoding error if I refer to the token using the <> syntax. This happens on 
MoarVM, it works fine on JVM.

This runs OK:

  perl6 -c -e 'grammar { token TOP { <numero>+ }; token número {<< \d+ >>} }'
  Syntax OK

Now, if I reference the new token (número) I get an error:

  perl6 -c -e 'grammar { token TOP { <número>+ }; token número {<< \d+ >>} }'
  ===SORRY!===
  Error encoding ASCII string: could not encode codepoint 250

The same code on JVM runs OK:

  perl6-j -c -e 'grammar { token TOP { <número>+ }; token número {<< \d+ >>} }'
  Syntax OK

I'm running Linux Fedora 22. Both Rakudo 2015.11 and 2015.12 exhibit the error.