Dialyxir.Warnings.PatternMatchCovered (Dialyxir v1.4.5) View Source
The pattern match has a later clause that will never be executed, because a more general clause is higher in the matching order.
Example
defmodule Example do
def ok() do
unmatched(:error)
end
defp unmatched(_), do: :ok
defp unmatched(:error), do: :error
end