{"slug": "ruby-4-0-is-here-why-is-ai-still-writing-ruby-3-0", "title": "Ruby 4.0 Is Here. Why Is AI Still Writing Ruby 3.0?", "summary": "Ruby 4.0 has been released, but AI coding assistants still generate Ruby 3.0-era code, ignoring modern idioms like hash value omission and anonymous block parameters. This creates a feedback loop that slows adoption of new language features, raising concerns about AI's role in preserving outdated practices.", "body_md": "June 17, 2026\n\nArtificial intelligence has become an indispensable tool for Ruby developers.\n\nWe ask AI assistants to write methods, refactor services, generate RSpec tests, explain stack traces, and even architect new features. For many developers, AI is no longer an experiment—it’s part of the daily workflow.\n\nThat’s exactly why we should expect more from it.\n\nIf I’m writing a Ruby 4.0 application, I don’t want my AI assistant producing Ruby that looks like it came from 2021.\n\n### Valid Ruby Isn’t Enough\n\nOne of the most common arguments is that AI-generated code is “still correct.”\n\nTechnically, that’s true.\n\nBut correctness isn’t the only measure of quality.\n\nImagine asking for Rails 8 code and receiving Rails 6 patterns. The application would probably still work, but you wouldn’t consider that a good answer.\n\nThe same applies to Ruby.\n\nWhen I ask an AI to generate Ruby code, I expect it to use the idioms of the current language—not simply produce syntax that happens to compile.\n\n### The Evidence Is Everywhere\n\nTake Ruby’s hash value omission syntax.\n\nInstead of writing:\n\n```\ncreate_session(user: user)\n```\n\nModern Ruby allows:\n\n```\ncreate_session(user:)\n```\n\nYet most AI assistants still default to the longer version.\n\nThe same happens with hashes:\n\n```\n{  user:,  project:,  account:}\n```\n\nInstead, AI frequently generates:\n\n```\n{  user: user,  project: project,  account: account}\n```\n\nAnother example is Ruby’s anonymous block parameter.\n\nModern Ruby lets us write:\n\n```\nnumbers.map { it * 2 }\n```\n\nYet AI almost always produces:\n\n```\nnumbers.map { |number| number * 2 }\n```\n\nNone of these examples are wrong.\n\nThey’re simply not modern Ruby.\n\n### Why Does This Matter?\n\nSome developers might dismiss this as a stylistic preference.\n\nI don’t think it is.\n\nProgramming languages evolve because their communities identify better ways to express ideas.\n\nCleaner syntax reduces repetition.\n\nModern idioms improve readability.\n\nNew language features exist because the Ruby core team believed they made the language better.\n\nIf AI assistants ignore those improvements, they’re teaching developers habits from older versions of Ruby.\n\nThat’s not just a cosmetic issue.\n\nIt’s a quality issue.\n\n### AI Is Creating a Feedback Loop\n\nThere’s another consequence that’s easy to overlook.\n\nAI models learn from existing code.\n\nDevelopers increasingly learn from AI.\n\nThat creates a feedback loop.\n\n- Ruby introduces a new feature.\n- AI rarely generates it because it appears infrequently in training data.\n- Developers continue seeing the old syntax.\n- Developers keep writing the old syntax.\n- Future AI models train on even more old syntax.\n\nThe result is that modern Ruby features spread more slowly than they should.\n\nIronically, the tools designed to accelerate development may also be slowing the adoption of the language itself.\n\n### “Just Use RuboCop”\n\nA common response is to let RuboCop fix everything.\n\nAnd yes, RuboCop can automatically rewrite:\n\n```\n{  user: user,  project: project}\n```\n\ninto:\n\n```\n{  user:,  project:}\n```\n\nThat’s useful.\n\nBut it also misses the point.\n\nRuboCop is a formatter.\n\nAn AI coding assistant is supposed to be a programming assistant.\n\nThose are different responsibilities.\n\nIf every AI-generated snippet requires another tool to modernize it, then the AI isn’t producing the best answer available.\n\nIt’s producing an acceptable first draft.\n\nDevelopers deserve better than that.\n\n### This Is Bigger Than Hash Syntax\n\nThis isn’t really about user: versus user: user.\n\nIt’s about whether AI keeps pace with the languages it claims to support.\n\nRuby continues to evolve.\n\nDevelopers upgrade.\n\nFrameworks evolve.\n\nStyle guides change.\n\nAI coding assistants should evolve alongside them.\n\nIf they don’t, they risk becoming one of the strongest forces preserving outdated coding practices.\n\n### Raising the Standard\n\nAI has dramatically improved developer productivity.\n\nThere’s no question about that.\n\nBut as these tools become trusted programming partners, our expectations should increase as well.\n\nProducing code that merely works is no longer enough.\n\nThe best AI coding assistants should understand the current language, embrace modern idioms, and generate code that reflects today’s Ruby—not yesterday’s.\n\n**Ruby 4.0** is already here.\n\nIt’s time for AI to catch up.", "url": "https://wpnews.pro/news/ruby-4-0-is-here-why-is-ai-still-writing-ruby-3-0", "canonical_source": "https://rubystacknews.com/2026/06/17/ruby-4-0-is-here-why-is-ai-still-writing-ruby-3-0/", "published_at": "2026-06-18 11:15:59+00:00", "updated_at": "2026-06-18 11:23:34.320545+00:00", "lang": "en", "topics": ["large-language-models", "ai-tools", "developer-tools"], "entities": ["Ruby", "AI", "RuboCop", "Rails"], "alternates": {"html": "https://wpnews.pro/news/ruby-4-0-is-here-why-is-ai-still-writing-ruby-3-0", "markdown": "https://wpnews.pro/news/ruby-4-0-is-here-why-is-ai-still-writing-ruby-3-0.md", "text": "https://wpnews.pro/news/ruby-4-0-is-here-why-is-ai-still-writing-ruby-3-0.txt", "jsonld": "https://wpnews.pro/news/ruby-4-0-is-here-why-is-ai-still-writing-ruby-3-0.jsonld"}}