local function id(x) return x end local function comp(f) return function(g) return function(x) return f(g(x)) end end end local id2 = comp(id)(id) local nil2 = id2(nil) local a : any = nil local b : nil = nil local c : (nil) -> nil = nil local d : (any & nil) = nil local e : any? = nil local f : number = 123 return id2(nil2)