[perl #128810] Leading multi-line declarator block on role breaks stubs in composition

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# New Ticket Created by  Faye 
# Please include the string:  [perl #128810]
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# <URL: https://rt.perl.org/Ticket/Display.html?id=128810 >


<ShimmerFairy> m: #|(abc) role A { method foo { ... } }; class B does A { 
method foo { "OK" } }; say B.foo
<camelia> rakudo-moar f1313d: OUTPUT«===SORRY!=== Error while compiling 
<tmp>␤Method 'foo' must be implemented by A because it is required by a role␤at 
<tmp>:1␤»
<ShimmerFairy> m: #|abc␤role A { method foo { ... } }; class B does A { method 
foo { "OK" } }; say B.foo
<camelia> rakudo-moar f1313d: OUTPUT«OK␤»
<ShimmerFairy> m: #|[[[abc]]]␤role A { method foo { ... } }; class B does A { 
method foo { "OK" } }; say B.foo
<camelia> rakudo-moar f1313d: OUTPUT«===SORRY!=== Error while compiling 
<tmp>␤Method 'foo' must be implemented by A because it is required by a role␤at 
<tmp>:2␤»

It specifically has to be a _leading_ declarator block, and as seen above it 
has to be the multi-line (delimited) variety. The single-line variant works 
fine. Trailing declarator blocks don't break this either. As seen above, the 
specific choice of delimiters on the declarator block is irrelevant.