How to debug why doesn't ctags find particular function declaration?

Question

I use ctags to generate the tags file for a TypeScript project.

$ ctags --version
Universal Ctags 6.0.0, Copyright (C) 2015-2022 Universal Ctags Team
Universal Ctags is derived from Exuberant Ctags.
Exuberant Ctags 5.8, Copyright (C) 1996-2009 Darren Hiebert
  Compiled: Feb  1 2023, 00:00:00
  URL: https://ctags.io/
  Output version: 0.0
  Optional compiled features: +wildcards, +regex, +iconv, +option-directory, +xpath, +json, +interactive, +sandbox, +yaml, +packcc, +optscript

But it doesn't find nested function declarations. For JavaScript it does find them (the same file, except for the file type extension).

Just in case, here is my minimal reproducible case (the bar function is not matched):

'use strict';
foo();

function foo() {
  for (const i of [0, 1, 2,]) {
    bar(i);
  }

  function bar(ind: number) {
    console.log(ind);
  }
}

Where should I look? I'm reading the documentation, but it seems to be pretty voluminous.

Answer 1

In the question I stated that with JavaScript files tags for nested functions work. But it turned out to be an exaggeration.

If one has a js file:

'use strict';
foo();
bar();

function foo() {
  for (const i of [0, 1, 2,]) {
    bar(i);
  }

  function bar(ind) {
    console.log(ind);
  }
}

function bar() {
  return '123';
}

And tries to use a tag for the first call of bar(), it goes to the wrong declaration, that's because ctags have notions of tag_name and ex_cmd (usually a regexp to search for the place in the file). And in this case there are 2 bar tags. Although the ex commands are different and in this case should correctly find the 2 declarations (provided the indentation level is different, and of course it's not generally the case), the name is always the same (I simply don't see a way to distinguish names of 2 functions, which have a same name). So there is no way (at least it's a very non-trivial thing to do) to correctly go to the actual declaration.

But practically, it's not a big problem, since such nested functions usually are not that far in the file, so it's better just to search with the text editor default functionality.

And for non-nested declarations ctags seems to work pretty well out of the box.

So currently I've decided not to bother with this, and not to try to make it work with TypeScript, since it won't work perfectly anyway (as I explained, it doesn't for JavaScript). Just use text search when trying to find a nested function.