Get dialyzer warnings working in umbrella apps.

[hworld]

Should fix #59

I added a simple test, however I couldn't actually get it to fail with the current code, with the current .tool-versions of elixir/erlang in the project. I have tested the fix locally as a vscode extension, though.

[axelson]

This is looking good, just one small comment on the code.

Although testing this with Elixir 1.10.2 on an umbrella project results in multiple errors like:

07:09:03.759 [error] Task #PID<0.115.0> started from #PID<0.1955.0> terminating
** (MatchError) no match of right hand side value: false
    (elixir 1.10.2) src/elixir_erl_var.erl:14: :elixir_erl_var.translate/4
    (elixir 1.10.2) src/elixir_erl_pass.erl:464: anonymous fn/5 in :elixir_erl_pass.translate_map/4
    (stdlib 3.10) lists.erl:1354: :lists.mapfoldl/3
    (elixir 1.10.2) src/elixir_erl_pass.erl:462: :elixir_erl_pass.translate_map/4
    (stdlib 3.10) lists.erl:1354: :lists.mapfoldl/3
    (elixir 1.10.2) src/elixir_erl_clauses.erl:20: :elixir_erl_clauses.match/3
    (elixir 1.10.2) src/elixir_erl_clauses.erl:28: :elixir_erl_clauses.clause/6
    (elixir 1.10.2) src/elixir_erl.erl:225: :elixir_erl.translate_clause/3
Function: &:erlang.apply/2
    Args: [#Function<8.15981531/1 in ElixirLS.LanguageServer.Dialyzer.update_stale/4>, [".elixir_ls/build/test/consolidated/Elixir.Inspect.beam"]]

beam files:

• .elixir_ls/build/test/consolidated/Elixir.Phoenix.Param.beam
• .elixir_ls/build/test/consolidated/Elixir.Jason.Encoder.beam
• .elixir_ls/build/test/consolidated/Elixir.Collectable.beam
• .elixir_ls/build/test/consolidated/Elixir.Inspect.beam
• .elixir_ls/build/test/consolidated/Elixir.Phoenix.HTML.FormData.beam

In my testing this error doesn't appear on a non-umbrella project on 1.9 or 1.10, or on an umbrella project running 1.9. And the errors do prevent the dialyzer warnings from being reported.

So this error appears to be related to dialyzer and protocol consolidation. It is possible that this is an Elixir bug, although it's quite possible that this is caused by ElixirLS using some private Elixir module/function. This error doesn't necessarily block this PR, but it would be great to resolve it with this PR since I haven't been able to trigger this error without using this PR.

[asummers]

@axelson Does that happen on a fresh build of the project? Dialyzer has issues with protocol consolidation but I'm wondering if you just need to clear build or something on the language bump.

[hworld]

I've updated the PR with the helper functions below. I've actually written this using Elixir 1.10.2 and OTP 22.2.8 and tested on an umbrella app with 3 apps and quite a few dependencies and it's been working just fine. I'm not sure how to reproduce what you've been seeing @axelson.

[axelson]

@asummers it appears that you are correct and after a rm -rf .elixir_ls this code is working great!

Thanks @hworld! ❤️