Using go fix to modernize Go code

I really liked this part:

In December 2024, during the frenzied adoption of LLM coding assistants, we became aware that such tools tended—unsurprisingly—to produce Go code in a style similar to the mass of Go code used during training, even when there were newer, better ways to express the same idea. Less obviously, the same tools often refused to use the newer ways even when directed to do so in general terms such as “always use the latest idioms of Go 1.25.” In some cases, even when explicitly told to use a feature, the model would deny that it existed. [...] To ensure that future models are trained on the latest idioms, we need to ensure that these idioms are reflected in the training data, which is to say the global corpus of open-source Go code.

I think tooling that can modify your source code to make it more modern is really cool stuff. OpenRewrite comes to mind for Java, but nothing comes to the top of my mind for other languages. And heck, I into recently learned about OpenRewrite and I've been writing Java for a long time.

Even though I don't like Go, I acknowledge that tooling like this built right into the language is a huge deal for language popularity and maturity. Other languages just aren't this opinionated about build tools, testing frameworks, etc.

I suspect that as newer languages emerge over the years, they'll take notes from Go and how well it integrates stuff like this.

The self-service analysis tools angle is the most underrated part of this. Being able to write custom fixers scoped to your own codebase solves a real pain point.

We maintain a large Go monorepo and every internal API migration turns into a grep+sed adventure. Half the time someone misses edge cases, the other half the sed pattern breaks on multiline. Having an AST-aware rewriter that understands Go's type system is a massive upgrade over regex hacks.

The -diff preview flag also makes this practical for CI. Run go fix -diff, fail if output is non-empty. That alone could replace a bunch of custom linters people maintain.

Its tooling like this that really makes golang an excellent language to work with. I had missed that rangeint addition to the language but with go fix I'll just get that improvement for free!

Real kudos to the golang team.

Go and its long established conventions and tools continues to be a massive boon to my agentic coding.

We have `go run main.go` as the convention to boot every apps dev environment, with support for multiple work trees, central config management, a pre-migrated database and more. Makes it easy and fast to dev and test many versions of an app at once.

See https://github.com/housecat-inc/cheetah for the shared tool for this.

Then of course `go generate`, `go build`, `go test` and `go vet` are always part of the fast dev and test loop. Excited to add `go fix` into the mix.

I wonder if you could make a language that is NOT backward compatible if you develop a tool like this alongside it.