[AlchemistCamp]

Unless you've worked with Clojure or another immutable, dynamically-typed language with pattern matching, you probably don't have a good mental model for what this would look like. It's a completely different story from a language like Python or JavaScript.

Immutability and pattern-matching get you at least the 80-20 of what a rigid type system does for larger code bases, and your team won't have to be as large when you're using a language like Elixir or Clojure as it would with older, more entrenched languages.

[turdprincess]

I feel like a common refactor in a large project might be a complete redefinition of a model layer exposed via a bunch of structs.

How does immutability or patter matching save me from runtime errors caused by changing the fields or types inside a struct? Wouldn’t the pattern matching just fail and go down the wrong code path since it was matching for the old pattern?

I feel like immutability is great, pattern matching is great, but static typing is also great and there is no reason why it can’t happily live along side the other two.

[AlchemistCamp]

In this case, the question is moot.

Elixir structs have compile-time checks: https://elixir-lang.org/getting-started/structs.html