Failed to format warning: @spec a:none | ...

[lukaszsamson]

Environment

• Elixir & Erlang/OTP versions (elixir --version): Erlang/OTP 22 [erts-10.6] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [hipe] Elixir 1.9.4 (compiled with Erlang/OTP 22)
• Which version of Dialyxir are you using? (cat mix.lock | grep dialyxir): master @ 62310a9cbcbb88a9ec08061d93946bf0f096bbbc

  Current behavior

  
  Failed to format warning:
  "@spec a:none | %{:active_param => pos_integer(), :signatures => [%{:name => binary(), :params => [binary()]}]}\ndef a() do\n  :ok\nend\n"

Legacy warning: lib/elixir_sense/providers/signature.ex:18: The success typing for 'Elixir.ElixirSense.Providers.Signature':find/3 implies that the function might also return #{'active_param':=non_neg_integer(), 'pipe_before':=boolean(), 'signatures':=maybe_improper_list()} but the specification return is 'none' | #{'active_param':=pos_integer(), 'signatures':=[#{'name':=binary(), 'params':=[binary()]}]}

[asummers]

You have code in the wild that does that? Awesome! Would you mind giving me an example so I can improve the docs?

[lukaszsamson]

@asummers to reproduce

1. clone https://github.com/elixir-lsp/elixir_sense
2. in mix.exs add :overspecs dialyzer flag
3. (optional ) bump dialyxir to github master
4. mix deps.get && mix dialyzer