The Y combinator causes problems with typing (it has an infinite recursive type), so I'm curious what solution they came up with.
In any case, if calling a lambda function from within itself is going to take more than a single line of straightforward code, then I'm afraid the solution still doesn't cut it for practical purposes.
They could've done something similar to what you do when you implement a functional language in C and used a union to represent every possible return type, and included functions (closures if you will) in that union, then you solve the problem of the infinite type.
From http://www.ioccc.org/2014/whowon.html
We'll have to patiently await publication of the source though...