Require Circuit::Config implement Clone instead of Copy

examples/circuit-layout.rs

@@ -13,6 +13,7 @@ fn main() {
     #[derive(Copy, Clone, Debug)]
     pub struct Variable(Column<Advice>, usize);
 
+    #[derive(Clone)]
     struct PLONKConfig {
         a: Column<Advice>,
         b: Column<Advice>,

src/plonk/circuit.rs

@@ -206,7 +206,7 @@ pub trait Assignment<F: Field> {
 /// [`ConstraintSystem`] implementation.
 pub trait Circuit<F: Field> {
     /// This is a configuration object that stores things like columns.
-    type Config: Copy;
+    type Config: Clone;
 
     /// The circuit is given an opportunity to describe the exact gate
     /// arrangement, column arrangement, etc.

src/plonk/prover.rs

@@ -182,7 +182,7 @@ pub fn create_proof<C: CurveAffine, T: TranscriptWrite<C>, ConcreteCircuit: Circ
             };
 
             // Synthesize the circuit to obtain the witness and other information.
-            circuit.synthesize(&mut witness, config)?;
+            circuit.synthesize(&mut witness, config.clone())?;
 
             let witness = witness;