`until` gives default value if expression is never matched in array

[ajusa]

 [1, 2, 4].assertMatch([until 3, @a, .._]); echo a

In this case, 3 doesn't appear in the array so I'd expect it to not match. Instead, this prints 0 for some reason - does it just fail to find a match, so the default value for the type is used instead?