As an aside: Arrays are treated in the same way when doing smart matching:

use feature qw(say);

say qq(no match) unless (1, 4, 18) ~~ 4;
say qq(match) if (1, 4, 18) ~~ 18;
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results in

no match

match
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I tripped over this, too, see http://www.perlmonks.org/?node_id=687969.