The clause on line X cannot be reached

[eksperimental]

This is my project and commit
https://github.com/eksperimental/beam_langs_meta_data/tree/26ecd958475bedd5c0e4204814e7437484acdff4

Error:

lib/beam_langs_meta_data.ex: The clause on line 395 cannot be reached

https://github.com/eksperimental/beam_langs_meta_data/blob/26ecd958475bedd5c0e4204814e7437484acdff4/lib/beam_langs_meta_data.ex#L395

The line is reachable from IEx though

[erszcz]

This does not seem to be connected with #72. This means it's likely connected with multiple spec clauses on the function in question, that is josefs/Gradualizer#410. This is confirmed by the fact that the warning goes away when we rewrite the spec to the following (less strict) version:

-  @spec compatibility({:elixir, :otp}) :: %{
-          elixir_version_key => nonempty_list(otp_version_key)
-        }
-  @spec compatibility({:otp, :elixir}) :: %{
-          otp_version_key => nonempty_list(elixir_version_key)
+  @spec compatibility({:elixir, :otp} | {:otp, :elixir}) :: %{
+          (elixir_version_key | otp_version_key) => nonempty_list(otp_version_key) | nonempty_list(elixir_version_key)
         }

[baldwindavid]

I'm testing out gradient on a PR in the ExWaiter package and seem to be hitting cases where a typespec does not cover multiple function heads...
https://github.com/baldwindavid/ex_waiter/pull/3/files#diff-a502442c0bd637c012b9c3bd3788d431af95331497257e34e1a53bb8a5446f49R258