e.slice is not a function

[xogeny]

I performed what looked like a normal query in the exerciser and got this error message: e.slice is not a function.

Here is a link to the exerciser that demonstrates the issue: http://try.jsonata.org/BJritdUhG

[andrew-coleman]

It looks like this is another example of an expression where the first step should not iterate over the input array (similar to the array constructor which gets special treatment)