没有安装Elixir(Elixir not installed)

 我刚刚克隆了Elixir / Phoenix项目，但无法执行任何混合任务。 我一直elixir 1.5.1 not installed 。 我没有得到它，因为我安装了Elixir。 如果我从项目之外的任何其他文件夹运行elixir --version ，我可以看到我在Elixir 1.5.1上运行。 只是在这个项目中，我一直得到没有安装elixir的错误。 
 
 可能是什么问题呢？ mix.exs文件的内容如下所示：项目部分 
 
def project do
[
  app: :real_world,
  version: "0.0.1",
  elixir: "~> 1.5",
  elixirc_paths: elixirc_paths(Mix.env),
  compilers: [:phoenix, :gettext] ++ Mix.compilers,
  start_permanent: Mix.env == :prod,
  aliases: aliases(),
  deps: deps(),
  test_coverage: [tool: ExCoveralls],
]
end
 
 和deps部分： 
 
defp deps do
[
  {:phoenix, "~> 1.3.0"},
  {:phoenix_pubsub, "~> 1.0"},
  {:phoenix_ecto, "~> 3.2"},
  {:postgrex, "~> 0.13.3"},
  {:gettext, "~> 0.11"},
  {:proper_case, "~> 1.0.0"},
  {:cowboy, "~> 1.1"},
  {:comeonin, "~> 3.2"},
  {:guardian, "~> 0.14.5"},
  {:excoveralls, "~> 0.7", only: [:dev, :test]},
  {:credo, "~> 0.8.5", only: [:dev, :test]},
  {:ex_machina, "~> 2.0", only: :test},
  {:plug, "~> 1.0"},
  {:corsica, "~> 1.0"}
]
end

I just cloned an Elixir/Phoenix project but can't run any mix tasks. I keep getting elixir 1.5.1 not installed. I don't get it though since I have Elixir installed. If I run elixir --version from any other folder outside the project I can see I am running on Elixir 1.5.1. It's just inside this project that I keep getting the error that elixir is not installed. 
 
What could be the problem? The contents of the mix.exs file look like this: The project section
 
def project do
[
  app: :real_world,
  version: "0.0.1",
  elixir: "~> 1.5",
  elixirc_paths: elixirc_paths(Mix.env),
  compilers: [:phoenix, :gettext] ++ Mix.compilers,
  start_permanent: Mix.env == :prod,
  aliases: aliases(),
  deps: deps(),
  test_coverage: [tool: ExCoveralls],
]
end
 
And the deps section:
 
defp deps do
[
  {:phoenix, "~> 1.3.0"},
  {:phoenix_pubsub, "~> 1.0"},
  {:phoenix_ecto, "~> 3.2"},
  {:postgrex, "~> 0.13.3"},
  {:gettext, "~> 0.11"},
  {:proper_case, "~> 1.0.0"},
  {:cowboy, "~> 1.1"},
  {:comeonin, "~> 3.2"},
  {:guardian, "~> 0.14.5"},
  {:excoveralls, "~> 0.7", only: [:dev, :test]},
  {:credo, "~> 0.8.5", only: [:dev, :test]},
  {:ex_machina, "~> 2.0", only: :test},
  {:plug, "~> 1.0"},
  {:corsica, "~> 1.0"}
]
end

原文：https://stackoverflow.com/questions/48068976