Updated to work with latest Elixir beam paths.

.gitignore

@@ -1,4 +1,4 @@
-/ebin
+/_build
 /deps
 .depsolver.plt
 erl_crash.dump

lib/dialyzer.ex

@@ -9,7 +9,7 @@ defmodule Mix.Tasks.Dialyzer do
     -Wunmatched_returns -Werror_handling -Wrace_conditions -Wunderspecs
 
   You can define a dialyzer_flags key in your Mix project config to override defaults.
-  You can also include a dialyzer_paths key to override default path (only ebin)
+  You can also include a dialyzer_paths key to override default path (only Mix.Project.app_path()/ebin)
   
   e.g.
     def project do
@@ -37,7 +37,7 @@ defmodule Mix.Tasks.Dialyzer do
       |> join(" ")
   end
 
-  defp dialyzer_paths, do: (Mix.project[:dialyzer][:paths] || ["ebin"]) |> join(" ")
+  defp dialyzer_paths, do: (Mix.project[:dialyzer][:paths] || [ Path.join(Mix.Project.app_path, "ebin") ]) |> join(" ")
 
 end
 

lib/dialyzer.plt.ex

@@ -135,5 +135,10 @@ defmodule Mix.Tasks.Dialyzer.Plt do
     |> is_list
   end
 
-  defp ex_lib_path, do: "#{to_string(:code.lib_dir(:elixir))}/.."
+  defp ex_lib_path do
+    code_dir = Path.join(:code.lib_dir(:elixir), "..")
+    ~w[eex elixir ex_unit iex mix]
+    |> Enum.map(&Path.join([ code_dir, &1, "ebin" ]))
+    |> Enum.join(" ")
+  end
 end