Given an input object like this:

{
    "items": {
        "a": "b"
    }
}

I made a mistake in how I interpreted the input, and used every like this:

allow if {
    some key in ["a", "b", "c"]
    every item in input.items[key] {
        item == "foo"
    }
}

This is non-sensical, as input.items["a"] will return the string "b" and not a collection, but surprisingly this passed.

Not just a runtime issue either, as the this also passes:

every item in 1 {
    item == "foo"
}

I'd expect the every keyword to fail evaluation on anything but a valid collection, both at compile time and runtime.