Require Import PrimInt63. Set Implicit Arguments. Open Scope int63_scope. Check (eq_refl : addcarryc 2 3 = C0 6). Check (eq_refl (C0 6) <: addcarryc 2 3 = C0 6). Check (eq_refl (C0 6) <<: addcarryc 2 3 = C0 6). Definition compute1 := Eval compute in addcarryc 2 3. Check (eq_refl compute1 : C0 6 = C0 6). Check (eq_refl : addcarryc 9223372036854775807 2 = C1 2). Check (eq_refl (C1 2) <: addcarryc 9223372036854775807 2 = C1 2). Check (eq_refl (C1 2) <<: addcarryc 9223372036854775807 2 = C1 2). Definition compute2 := Eval compute in addcarryc 9223372036854775807 2. Check (eq_refl compute2 : C1 2 = C1 2).