From 92029393f6057018898135ddabe58d44fa60c536 Mon Sep 17 00:00:00 2001
From: Sean Bowe <ewillbefull@gmail.com>
Date: Wed, 22 Nov 2017 22:55:32 -0700
Subject: [PATCH] Guarantee that variables are Copy+Clone.

---
 src/lib.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index c12fc72..e33b3db 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -91,7 +91,7 @@ impl fmt::Display for SynthesisError {
 }
 
 pub trait ConstraintSystem<E: Engine>: Sized {
-    type Variable;
+    type Variable: Sized + Copy + Clone;
 
     /// Represents the type of the "root" of this constraint system
     /// so that nested namespaces can minimize indirection.
@@ -336,7 +336,7 @@ impl<'cs, E: Engine, CS: ConstraintSystem<E>> ConstraintSystem<E> for &'cs mut C
 fn test_cs() {
     use pairing::bls12_381::{Bls12, Fr};
 
-    #[derive(PartialEq)]
+    #[derive(PartialEq, Copy, Clone)]
     enum Var {
         Input(usize),
         Aux(usize)