Some IDEs like rubymine allow this. On vscode if I can't work out what a function does from the name I just do a full code search for 'def method_name` and it usually brings up the function I need.
Not in Rails. Too much metaprogramming-generated never-defined stuff going on. Often makes diving into inherited Rails codebases pretty unpleasant. Especially if they don't have a solid test suite, which IME most in the wild do not (not Rails' fault, that's true of most code ecosystems).
Maybe you can get away with a module system that works that way in something like ocaml where it’s always possible to tell what is being referred to statically — but in a dynamic language - the level of obfuscation this induces is absolutely nuts