How to forbid simpl tactic to unfold arithmetic expressions?

Question

The simpl tactic unfolds expressions like 2 + a to \"match trees\" which doesn\'t seem simple at all. For example:

Answer 1

You can tweak how the simpl tactic behaves so you get less matches.

Require Import Coq.ZArith.ZArith.

Goal forall i:Z, ((fun x => (x + i)%Z) 3%Z = (i + 3)%Z).
Arguments Z.add x y : simpl nomatch.
simpl.

Read more about it here.

Otherwise you can use other tactics that allow you to choose how to reduce. cbn beta, for example.