[perl #74638] [BUG] coercion to integer not working in a class to index array

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# New Ticket Created by  Richard Hainsworth 
# Please include the string:  [perl #74638]
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# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=74638 >


from #perl6 Apr 24

this works:
rakudo: class B {has @.a;has $.u;method m { for $.u .. 4 { .WHAT.say; 
say @.a[$_] }}}; my B $x.=new(:a<a b c d>,:u(3));$x.m
p6eval: rakudo de2ad3: OUTPUT«Int()␤d␤Int()␤␤»


these dont but should, I think:
attribute is cast to Num.

rakudo: class B {has @.a;has $.u;method m { for $.u .. 4 { .WHAT.say; 
say @.a[+$_] }}}; my B $x.=new(:a<a b c d>,:u(+'3'));$x.m
p6eval: rakudo de2ad3: OUTPUT«Num()␤No applicable candidates found to 
dispatch to for 'postcircumfix:<[ ]>'. Available candidates are:␤Mu : 
Int $i;; *%_)␤Mu : Block $b;; *%_)␤Mu : !whatever_dispatch_helper ;; 
*%_)␤␤current instr.: '!postcircumfix:<[ ]>' pc 10885 
(src/builtins/Role.pir:73)␤»

attribute is cast to Str

finanalyst: rakudo: class B {has @.a;has $.u;method m { for $.u .. 4 { 
.WHAT.say; say @.a[+$_] }}}; my B $x.=new(:a<a b c d>,:u('3'));$x.m
p6eval: rakudo de2ad3: OUTPUT«Str()␤No applicable candidates found to 
dispatch to for 'postcircumfix:<[ ]>'. Available candidates are:␤Mu : 
Int $i;; *%_)␤Mu : Block $b;; *%_)␤Mu : !whatever_dispatch_helper ;; 
*%_)␤␤current instr.: '!postcircumfix:<[ ]>' pc 10885 
(src/builtins/Role.pir:73)␤»