[perl #126318] [BUG] trait 'is default' on attributes has no effect

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# New Ticket Created by  Tobias Leich 
# Please include the string:  [perl #126318]
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say class { has Int $.foo is default(0) }.new.foo
rakudo-moar 025ec1: OUTPUT«(Int)␤»

class Foo { has Int $.foo is default(0) }; say Foo.new.foo
rakudo-moar 025ec1: OUTPUT«(Int)␤»

I would expect that foo is zero in both cases.