Require Import Int63. Set Implicit Arguments. Open Scope int63_scope. Check (eq_refl : 1 <=? 1 = true). Check (eq_refl true <: 1 <=? 1 = true). Check (eq_refl true <<: 1 <=? 1 = true). Definition compute1 := Eval compute in 1 <=? 1. Check (eq_refl compute1 : true = true). Check (eq_refl : 1 <=? 2 = true). Check (eq_refl true <: 1 <=? 2 = true). Check (eq_refl true <<: 1 <=? 2 = true). Definition compute2 := Eval compute in 1 <=? 2. Check (eq_refl compute2 : true = true). Check (eq_refl : 9223372036854775807 <=? 0 = false). Check (eq_refl false <: 9223372036854775807 <=? 0 = false). Check (eq_refl false <<: 9223372036854775807 <=? 0 = false). Definition compute3 := Eval compute in 9223372036854775807 <=? 0. Check (eq_refl compute3 : false = false).