[perl #70720] Can't introspect constants in signatures

[Lewis Wall]

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[20:20] <quietfanatic> rakudo: say :(3).perl
[20:20] <+p6eval> rakudo 7347ec: :(Int ::TYPE_CAPTURE20 where all({ ... }))␤

I can't find a '3' anywhere inside that expression, or in any of the methods
on the Parameter object. I want my 3 back!