build_function does not seem to work for complex-valued functions

[nabil-atlam]

In this code, I have an expression for a complex-valued function that I am trying to build into a callable function. However, it does not evaluate the built function when given sample numerical inputs.

using Symbolics
@variables x::Float64
@variables fexpr::ComplexF64
dx = Differential(x)
fexpr = 1.0 + cis(x)
dfexpr = expand_derivatives(dx(fexpr))

_dfexpr = build_function(dfexpr, x)
df = eval(_dfexpr)
result = df(0.0)
println(result)