I am a maintainer on an open-source project named Semgrep (https://semgrep.dev/), which is a framework for linting/search/finding security bugs in code. For instance, to find calls to eval in Ruby, the search pattern is eval(...). Here’s a more complex example from Python in a live editor. We are just finishing adding a first version support for Ruby to semgrep (using the Tree-sitter parser from Github) and would love feedback / folks to beta test the parser accuracy.
Semgrep is useful if you have an idea for a lint/check/query that you can almost grep for, and you could write a rubocop rule for, but want something you can do fast + cheap and still be AST/syntax-aware.
Hope some folks find this useful; shoot me an email isaac at r2c dot dev if you’re interested!