inhabit vectors

cb021200 · Ralf Jung · db2da9af · cb021200
Commit cb021200 authored Mar 15, 2017 by Ralf Jung
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theories/vector.v theories/vector.v +10 -0

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--- a/theories/vector.v
+++ b/theories/vector.v
@@ -355,3 +355,13 @@ Proof.
 Qed.
 Lemma vlookup_insert_self {A n} i (v : vec A n) : vinsert i (v !!! i) v = v.
 Proof. by induction v; inv_fin i; intros; f_equal/=. Qed.
+
+(* Vectors can be inhabited. *)
+Global Instance vec_nil_inh T : Inhabited (vec T 0) := populate [#].
+
+Global Instance vec_inh T n : Inhabited T → Inhabited (vec T n).
+Proof.
+  intros HT. induction n; [apply _|].
+  destruct IHn as [v]. destruct HT as [x].
+  exact (populate (x:::v)).
+Qed.