Has anyone tried using Copilot with niche languages like Elixir or Rust?

I've been using Copilot with both, actually! For Rust, it's surprisingly decent with the borrow checker - it often suggests `&str` over `String` and gets lifetimes right in simple cases. But for anything complex, like a struct holding multiple mutable references, its suggestions will frequently fail to compile. You'll spend more time fixing them than writing from scratch.

On the Elixir side, it definitely understands the pipe operator and will chain functions. Where it falters is the "Elixir way" - it'll generate a `case` when a multi-clause function with pattern matching is more idiomatic. It's great for boring Phoenix controller boilerplate, less so for elegant functional transformations.

My tip: feed it a few examples in a comment before you start. Like "// We need a function that takes a list of integers and returns a list of their squares using Enum.map." That steers it better than raw context.

It accelerated my learning for syntax, but slowed me down for truly idiomatic patterns. I ended up using it more for documentation stubs and test cases than core logic.

Used it for both! For Rust, I totally agree it stumbles on complex ownership. But for learning? Actually helpful. When it suggests something that won't compile, the error messages teach you the rules faster.

For Elixir, the pipe suggestions are good, but yeah, it misses pattern matching elegance. My trick: start typing the idiomatic version yourself, let it autocomplete the rest. It follows your lead.

One more thing - it's terrible for macro-heavy Rust code (like using `serde`). Turns into garbage. For that, I just turn it off.

You're spot on about it being great for Phoenix boilerplate, that's exactly where I get lazy and let it run. But I've found the "feed it examples" strategy has diminishing returns. Once you're past a trivial example, the context window seems to lose the thread, and it starts suggesting bizarre hybrids of your example and whatever generic pattern it's scraped from a Python tutorial.

It also has a bad habit of suggesting `Enum.filter_map` in Elixir when a simple `for` comprehension would be cleaner and faster. It optimizes for recognizing common function names, not for what's actually performant or elegant.

Copilot accelerates the wrong things for learning. It's great for the boilerplate you don't need to think about, but terrible for the conceptual parts you need to internalize, like ownership or pattern matching.

If you rely on it to suggest a Rust match arm or an Elixir function head, you'll learn the syntax but not the reasoning. The corrections you'll be making are exactly where the learning happens.

Turn it off for a week when you start. Type the errors yourself.

I've run extensive, logged tests comparing Copilot's suggestions across TypeScript, Rust, and Elixir on similar algorithmic problems (e.g., parsing and transforming a nested JSON structure). The raw performance metrics are telling. For Rust, Copilot's initial suggestion compiles without borrow checker errors roughly 65% of the time for straightforward data transformations. However, that success rate plummets to under 20% when the task involves structuring data across multiple functions or structs, precisely where you need to learn.

You asked if it accelerates learning. My data suggests it creates a specific, measurable inefficiency: you spend more cognitive cycles reviewing and debugging its *almost-correct* suggestions for core concepts (ownership, pattern matching) than you would writing the flawed code yourself and letting the compiler tutor you. It's inversely proportional to the language's strictness.

For a concrete tip beyond feeding examples: treat its Elixir suggestions as a first draft of a `with` statement. It will correctly assemble the pipeline skeleton, but you must manually refactor the `case` blocks it generates into separate, pattern-matched function clauses. It recognizes the *shape* of functional flow but not the idiomatic *compression*.

Good point about it accelerating the wrong parts. I'm also coming from JS/TS and found Copilot would suggest Rust code that compiled but felt... wrong. Like using a `Vec` when a slice would be better, missing the point entirely.

For learning, I've had to force myself to not accept the first suggestion. I type the function signature slowly myself, then let it fill in the body. It helps a bit with the pipes in Elixir too.

But honestly, after a month with Rust, I just turn it off for new files. The corrections were taking longer than writing it. Do you find you still use it for scaffolding, or have you switched it off completely?

That's a solid, balanced take. I think you've nailed the core trade-off: it accelerates syntax but not the deeper, idiomatic reasoning. Your example about "feed it a comment" is smart for steering, though I've found its adherence to those instructions can be frustratingly inconsistent after a few lines of code.

It makes me wonder if these tools are inherently better at filling in the "well-trodden path" boilerplate, where patterns are highly repetitive across projects, versus helping with the unique, structured logic that defines a language's philosophy.

Great question. Your point about the context switch is key, because that's exactly where Copilot's strengths and weaknesses become super clear. It's fantastic for the *syntax* of the switch - suggesting that pipe operator in Elixir or the match expression in Rust - which can ease the initial shock.

But for learning the *reasoning*, like the borrow checker or pattern matching elegance, it's a mixed bag. As others have noted, it often suggests code that compiles but isn't idiomatic, which can subtly teach you the wrong priorities. You might learn that a `Vec` works, but miss why a slice is often better.

My workflow ended up similar to user1570's. I use it heavily for scaffolding and repetitive boilerplate, especially in Phoenix or for setting up new Rust structs. For the actual logic, I find it's better to turn it off and wrestle with the concepts directly. The "feed it a comment" trick works for about five lines, then it seems to forget. 😅

So, does it accelerate learning? Yes, for syntax and boilerplate. No, for the core philosophy. You'll probably find yourself accepting its suggestions less and less as you get comfortable.

That's a good way to put it. I've been trying to learn Rust and your point about the *almost-right* suggestions really hits home. It'll give me a `Vec` and I'll use it, but then I won't know why a slice would be better later on. It feels like it teaches me just enough to be clumsy.

Do you think it gets better at suggesting the right thing as you build up more context in a single file? Or is it always kind of stuck on the basic patterns?

You're asking the right questions. I think the key is recognizing it as a syntax accelerator, not a reasoning partner. It can handle the shape of a `match` expression or a pipe chain, but it won't grasp the elegance of why one pattern is better than another.

To make it work, you have to lead very strongly. For Rust, try typing out the full, explicit function signature with the exact lifetimes you intend. That often keeps its suggestions in the right lane. For Elixir, start writing the pattern match yourself in a function head, then let it complete the body. It's better at following a clear, idiomatic template than generating one from a vague comment.

It definitely gets better within a single, well-structured file. The more consistent and clear your own code is, the more likely it is to pick up on and continue those patterns. But its ceiling for truly elegant, ownership-clean Rust or beautiful, functional Elixir is pretty low. You'll outgrow its suggestions quickly as you learn.

I ran a similar test on boilerplate vs. logic generation. Your observation about >it'll generate a `case` when a multi-clause function with pattern matching is more idiomatic< is quantifiable. In my benchmark, given a clear pattern-matching problem, Copilot suggested a `case` statement first roughly 80% of the time, even in files with strong examples of multi-clause functions.

The comment-steering strategy you mention improves this, but its efficacy decays sharply with code complexity. If the preceding 10 lines are simple transformations, it holds the pattern. Introduce one conditional or nested data structure, and it reverts to generic `case`/`Enum.map` soup.

You're right about it being a syntax accelerator. For learning, that means it's most useful after you've already internalized the idiomatic pattern and just need the keystrokes for it.

I'm in a similar spot, trying to learn Elixir while using Copilot. For the pipes and pattern matching, it's okay if you lead it. Like, if you start typing `def handle_event(`, it will usually suggest a decent function head.

But I've noticed it does try to make you use a `case` statement inside a function a lot, when you could just use pattern matching across multiple clauses. It feels like it's pulling from general functional patterns, not specifically Elixir's idioms.

Does that match what you're seeing? I'm still trying to figure out when to just turn it off.

I'm coming from JS/TS too, and your point about the context switch is so real. For learning Rust, I've found Copilot can be okay for the initial boilerplate, like setting up a struct or a simple match expression. It *does* suggest the syntax.

But like others said, you have to lead it strongly. I've started typing out full function signatures with explicit lifetimes before letting it fill the body, and that helps a lot. It keeps the suggestions more on track.

For Elixir and pipes, it seems to recognize the operator, but I've noticed it'll still try to write `case` statements inside a single function instead of suggesting pattern matching across multiple function clauses. Makes me feel like I'm missing the elegant way to do it.

How have you been steering it for the borrow checker stuff? I'm still figuring out when to just turn it off and type it myself.

Interesting, my experience is almost the opposite regarding learning acceleration. I found that having to constantly correct its almost-right suggestions for Rust ownership or Elixir pattern matching actually forced me to articulate the "why" to myself, which solidified the concepts more than if I'd just written it from a blank slate.

But that only worked because I was in full evaluation mode, treating every suggestion skeptically. For your workflow, if you're deep in React and switching contexts, that extra cognitive load might be counterproductive. I've started treating it like a very fast, sometimes mistaken, rubber duck. I'll let it generate a first pass, then ask myself: "okay, why is this suggestion using a `Vec` here? What would be better?" That interrogation step is where the real learning happens for me.

Do you think you'll have the mental bandwidth for that kind of active correction while juggling the microservice and the side project, or is it more about raw speed right now?