If someone were to claim: no computer will ever be able to beat humans in code design, would you agree with that? If the answer is "no", then there's your proof.
But FYI “proof by negation” is better known as the fallacy of excluded middle when applied outside a binary logical system like this.
If you define "human" to be "average competent person in the field" then absolutely I will agree with it.
If someone were to claim: no computer will ever be able to beat humans in code design, would you agree with that? If the answer is "no", then there's your proof.