Document symbols could include local definitions

[michaelpj]

At the moment we include all the "top-level" stuff. But we could include local definitions as well. The thing that would be awkward is reflecting nested scopes, but often they are also associated with a symbol.

It might also be rather noisy, but arguably that's a client problem? e.g. things should be shown collapsed by default, if you open up a function, sure you get lots of stuff.

Examples to think about:

f x = g x
  where 
    g = ...

f x = 
  let g = ..
  in g x

f x =
   -- awkward nesting and shadowing
   let g = let g = ... in g
   in g x

f x = do
    -- nest g inside res? what if we discarded the result?
   res <- let g = ... in g x
   pure res

[wz1000]

We have an interval map in Development.IDE.Spans.LocalBindings that could be used to implement this

[sgillespie]

Hi, I've been hacking at this, and here's an example of how it looks in emacs with eglot:

The markup itself looks like this:

* * *
Local bindings:

```haskell
hf :: HieASTs a
rm :: RefMap a
<-- Snip -->
prettyNames :: [Text]

```
* * *

How is this?

[michaelpj]

I'm a little confused about where you're adding this? I thought the idea was to put it into the document symbols, so it would show up in the outline, or similar?

[sgillespie]

Thanks for responding, I completely misunderstood the description. Will attempt to add it to textDocument/documentSymbol