I’ve distilled my use case into a simple example. Essentially, I have an outer function that takes an input and generates a scalar from an inner function. I want ForwardDiff to treat this scalar as a constant when taking the derivative of the outer function, but ForwardDiff is (correctly) tracing the input through the inner function. How can I get ForwardDiff to “ignore” the inner function? I’ve tried deep-copying, but that doesn’t do the trick. Some example code:

```
using ForwardDiff
function f1(x)
return g(x)
end
function f2(x)
scalar = deepcopy(g(x));
return scalar;
end
function g(x)
return x^2
end
ForwardDiff.derivative(f1,3) # => 6
ForwardDiff.derivative(f2,3) # => 6, want this to be 0
```

In `f2`

, I want ForwardDiff to great `g(x)`

as a constant, and thus the derivative with respect to `x`

should be zero. Thanks in advance for any help!