[perl #126120] Cannot change native role attribute from consuming class

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# New Ticket Created by  Elizabeth Mattijsen 
# Please include the string:  [perl #126120]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=126120 >


[19:22:03]  <lizmat>    m: role R { has int $!a }; class A does R { method a() 
{ $!a = 42 } }; say A.new.a   # sigh
[19:22:03]  <+camelia>  rakudo-moar 97e47a: OUTPUT«Cannot assign to an 
immutable value␤  in method a at /tmp/xjfoxVcXDh:1␤  in block <unit> at 
/tmp/xjfoxVcXDh:1␤␤»
[19:22:25]  <lizmat>    m: role R { has Int $!a }; class A does R { method a() 
{ $!a = 42 } }; say A.new.a   # works fine if it is not a native
[19:22:25]  <+camelia>  rakudo-moar 97e47a: OUTPUT«42␤»