proposition: Theorem whd_match : forall n n' (w : word (S n)) (Heq : S n = S n'), whd w = whd (match Heq in (_ = N) return (word N) with | eq_refl => w end).
proof: Proof. intros. rewrite eq_rect_word_match. generalize dependent w. remember Heq as Heq'. clear HeqHeq'. generalize dependent Heq'. replace (n') with (n) by lia. intros. rewrite <- (eq_rect_eq_dec eq_nat_dec). reflexivity. Qed.
imports: Coq.Classes.Morphisms Coq.Classes.Morphisms_Prop Coq.Classes.Equivalence Coq.Arith.PeanoNat Coq.ZArith.BinInt  Coq.Arith.Arith Coq.NArith.NArith Coq.Bool.Bool Coq.ZArith.ZArith Coq.Logic.Eqdep_dec Coq.Logic.EqdepFacts Coq.Program.Tactics Coq.Program.Equality Coq.setoid_ring.Ring Coq.setoid_ring.Ring_polynom bbv.Nomega bbv.ZLib bbv.NatLib bbv.NLib bbv.N_Z_nat_conversions bbv.DepEq bbv.DepEqNat bbv.ReservedNotations Coq.micromega.Lia