Illegal atom key in tuple list is not detected

[RobertDober]

Precheck

• Take a look at the open issues and be sure that your issue is not already covered.
• Be sure your versions of Dialyxir and Erlex are up to date.

╰─> λ mix hex.search dialyxir                                                                                                                                [12:08:10]
Package   Description                                            Version  URL                               
dialyxir  Mix tasks to simplify use of Dialyzer in Elixir pr...  1.0.0    https://hex.pm/packages/dialyxir  

╭─>robert@roma ~/tmp/typestest                                                                                                                ❰1.10.4➤23.0.1❱ ⬡ 12.16.3 
╰─> λ mix hex.search erlex                                                                                                                                   [12:08:23]
Package  Description                                            Version  URL                              
erlex    Convert Erlang style structs and error messages to...  0.2.6    https://hex.pm/packages/erlex    
erlexec  OS Process Manager                                     1.17.5   https://hex.pm/packages/erlexec  

╭─>robert@roma ~/tmp/typestest                                                                                                                ❰1.10.4➤23.0.1❱ ⬡ 12.16.3 
╰─> λ mix deps                                                                                                                                               [12:08:30]
* erlex 0.2.6 (Hex package) (mix)
  locked at 0.2.6 (erlex) 2ed2e257
  ok
* dialyxir 1.0.0 (Hex package) (mix)
  locked at 1.0.0 (dialyxir) aeb06588
  ok

Environment

• Elixir & Erlang/OTP versions (elixir --version):

iex                                                                                                                                                    [12:09:45]
Erlang/OTP 23 [erts-11.0.1] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:1] [hipe]

Interactive Elixir (1.10.4) - press Ctrl+C to exit (type h() ENTER for help)

• Which version of Dialyxir are you using? (cat mix.lock | grep dialyxir):

cat mix.lock | grep dialyxir                                                                                                                           [12:08:35]
  "dialyxir": {:hex, :dialyxir, "1.0.0", "6a1fa629f7881a9f5aaf3a78f094b2a51a0357c843871b8bc98824e7342d00a5", [:mix], [{:erlex, ">= 0.2.6", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm", "aeb06588145fac14ca08d8061a142d52753dbc2cf7f0d00fc1013f53f8654654"},

Current behavior

• Describe current behavior. Include errors, stack traces, and any additional information that might be important here. No warnings are given when checking this code

defmodule Typestest do
  @moduledoc """
  Documentation for `Typestest`.
  """

  @type amap :: %{atom() => atom()}
  @type keys :: :alpha | :omega
  @type kwds :: [{keys(), integer()}]

  @spec dispatch(integer()) :: amap()
  def dispatch(n)
  def dispatch(0), do: %{zero: true}
  def dispatch(_), do: %{infinity: tru

  @spec kwds(integer()) :: kwds()
  def kwds(n)
  def kwds(0), do: [alpha: 1]
  def kwds(1), do: [beta: 2]
  def kwds(_), do: [omega: 24]

end

Expected behavior

• A short description of the expected behavior.

The returned value [beta: 2] does not trigger a warning.

Trying to shrink the error triggering case.... please stand by

[RobertDober]

Still no warning:

defmodule Typestest do
  @moduledoc false

  @type keys :: :alpha

  @spec key(integer()) :: keys()
  def key(n)
  def key(0), do: :alpha
  def key(_), do: :beta

end

I am beginning to believe that I miss something obvious here :face_with_head_bandage:

[RobertDober]

Ok feeling better now, as the following code

defmodule Typestest do
  @moduledoc false

  @type keys :: :alpha

  @spec key() :: keys()
  def key(), do: :beta

end

does indeed trigger

lib/typestest.ex:6:invalid_contract
The @spec for the function does not match the success typing of the function.

Function:
Typestest.key/0

Success typing:
@spec key() :: :beta

[asummers]

Dialyxir does not originate warnings, only calls and reformast ones spit out by Dialyzer for Elixir. Any missing Dialyzer features or incorrect behavior are issues with Erlang core and dialyzer.erl. There are unfortunately illegal problems Dialyzer will still accept. Playing with the Dialyzer flags (-Wunmatched and friends) increases the number of warnings you get.

[RobertDober]

I see sorry for having bothered you.

[asummers]

No trouble!