I just linked this ticket from https://rt.perl.org/Ticket/Display.html?id=81682, which is now closed but pointed to a similiar problem:
$ perl6-m -e 'my Int @a = 1, 2, 3; my Str $x = "foo"; @a[0] := $x; say @a[0];' foo It would be nice, if both variants (binding to a string directly and binding to a scalar variable of type Str) would be tested, once the type check is implemented