Coccinelle for C, used by Linux kernel devs for decades, here's an article from 2009:

https://lwn.net/Articles/315686

Also IDE tooling for C#, Java, and many other languages; JetBrains' IDEs can do massive refactorings and code fixes across millions of lines of code (I use them all the time), including automatically upgrading your code to new language features. The sibling comment is slightly "wrong" — they've been available for decades, not mere years.

Here's a random example:

https://www.jetbrains.com/help/rider/ConvertToPrimaryConstru...

These can be applied across the whole project with one command, rewriting however many problems there are.

Also JetBrains has "structural search and replace" which takes language syntax into account, it works on a higher level than just text like what you'd see in text editors and pseudo-IDEs (like vscode):

https://www.jetbrains.com/help/idea/structural-search-and-re...

https://www.jetbrains.com/help/idea/tutorial-work-with-struc...

For modern .NET you have Roslyn analyzers built in to the C# compiler which often have associated code fixes, but they can only be driven from the IDE AFAIK. Here's a tutorial on writing one:

https://learn.microsoft.com/en-us/dotnet/csharp/roslyn-sdk/t...

Rust has clippy nagging you with a bunch of modernity fixes, and sometimes it can autofix them. I learned about a lot of small new features that make the code cleaner through clippy.

Does anyone have experience transforming a typescript codebase this way? Typescript's LSP server is not powerful enough and doesn't support basic things like removing a positional argument from a function (and all call sites).

Would jscodeshift work for this? Maybe in conjunction with claude?

> but nothing comes to the top of my mind for other languages

"cargo clippy --fix" for Rust, essentially integrated with its linter. It doesn't fix all lints, however.

python has a number of these via pyupgrade, which are also included in ruff: https://docs.astral.sh/ruff/rules/#pyupgrade-up

Java and .NET IDEs have had this capabilities for years now, even when Eclipse was the most used one there were the tips from Checkstyle, and other similar plugins.

eslint had `--fix` since like 10 years, so this is not exactly new.