Private functions can't have contracts

[asianfilm]

You can't specify a contract for a private function.

For example:

defmodule Test do
  use Norm

  @contract public() :: :ok
  def public(), do: :ok

  @contract private() :: :ok
  defp private(), do: ok
end

Gives the error:

** (ArgumentError) contract for undefined function private/0

There's a strong argument that only contracts at a module's boundaries should have contracts (or tests). But the author has stated: "My goal is to build a system that allows you to validate any elixir data at any point in your stack."

My workaround for now is to make all my functions public.

PS: Take my flood of issues as evidence that I'm loving the library.

[keathley]

I think there's a case to be made for supporting contracts on defp. I'm certainly not opposed to it.

[wojtekmach]

In #29 we introduce foundation for contract reflection. The plan for reflection is to start it as private API, if it becomes public the question would be whether a contract for a private function should be public. I can see both sides of this: if reflection would be used as just a list of contracts (to e.g. re-use a contract elsewhere) then +1 for this; on the other hand if reflection would be used to see capabilities of the given module (what functions it has and what they require/provide) then imho it should be private, perhaps with a @contractp.