As we saw in this section, methods get transformed into state-machines. The compiler does this quite aggressively to all the functions to cover maximum ground without leaving anything behind. With that, it runs the risk of transforming functions that should be left un-touched, especially higher order functions. To prevent that from happening, you should wrap the function you intend to pass around in std.lambda. It’s just a wrapper but tells the compiler to skip its transformation.
Higher Order Functions are an experimental feature.