Compiling an assigned witness gives a confusing error message

[ThomasPiellard]

This code gives an error which is a bit confusing:

        // create witness for a given circuit
        good := &frontend.AddCircuit{
        		A: 1,
        		Z: 1,
        		B: 10,
        	}
       
        // the fields A, Z, B of the circuit are modified after Compile is called
	ccs, _ := frontend.Compile(ecc.BN254.ScalarField(), scs.NewBuilder, good)

       /* ... */

      witness, err := frontend.NewWitness(good, ecc.BN254.ScalarField())
      // ---> At this stage, the fields of the witness cannot be parsed, as Compile modified the fields of the structure representing the circuit
	

Describe the solution you'd like

modify Compile (the error occurs in chema.Walk(circuit, tVariable, variableAdder(/* */)) ) so that the fields of the circuit are left as they were