Source code on Github
module Test.Allable where

open import Class.Prelude
open import Class.Allable
open import Class.Decidable
open import Class.HasOrder

_ : ∀[ x  List   1  2  3  [] ] x > 0
_ = auto

_ : ∀[ x  just 42 ] x > 0
_ = auto

_ : ∀[ x  nothing ] x > 0
_ = auto

_ : ¬∀[ x  just 0 ] x > 0
_ = auto