More accurate autolink warnings line

[wojtekmach]

Demo:

[wojtekmach]

RobertDober/earmark_parser#140

[garazdawi]

When I saw your other PRs regarding warnings I was hoping the change in this PR was coming soon :) looks great! Now we just need the various LSPs to warn for this as well :)

[josevalim]

Absolutely beautiful.

[garazdawi]

Do you know of any way to fix this for Erlang as well? :elixir_error.emit_diagnostic/5 seems to get

[{elixir_compiler,'__FILE__',1,
                  [{file,"/home/eluklar/git/otp3/lib/stdlib/src/gen_statem.erl"},
                   {line,1180}]}]

as the stacktrace, instead of something that it can convert to a nice warning message.

[josevalim]

Elixir allows you to compile code outside of modules, but it does so by compiling the code inside a fake module with a fake __FILE__ function. So for a warning like that to appear, you need to be compiling code somewhere. Do you know where that could be?

Before printing stacktraces, Elixir explicitly matches on the :elixir_compiler.__FILE__/1 and knows it should show only the file info.

[garazdawi]

I managed to get a bit further by setting :module and :function in IO.warn. Now the warning I get looks like this:

warning: documentation references function "erlang:foo/1" but it is undefined or private
  (stdlib 5.1.1) .../lib/stdlib/src/gen_statem.erl:1181: :gen_statem.callback_mode/0

Still need to figure out how to get the code snippet printed, or is that something that mix does?

[wojtekmach]

printing snippet is an Elixir 1.16 feature!

[garazdawi]

Aha!

[garazdawi]

      warning: documentation references function "erlang:throws/1" but it is undefined or private
      │
 1181 │ `erlang:throws/1`
      │ ~~~~~~~~~~~~~~~~~
      │
      └─ /home/eluklar/git/otp3/lib/stdlib/src/gen_statem.erl:1181: :gen_statem (module)

      warning: documentation references type "t:callback_mode/0" but it is undefined or private
      │
 1338 │ -doc """
      │ ~~~~~~~~
      │
      └─ /home/eluklar/git/otp3/lib/stdlib/src/gen_statem.erl:1338: :gen_statem (module)

with an upgraded Elixir it works great for regular links. Custom links don't have the line number info though so they look a bit odd :) Looking forward to the same info being added about <a href>! :D

I'll submit a PR with the changes I had to do to make Erlang work.