Contracts confused by block with `Maybe`?

[indigoviolet]

  class Bar
    include Contracts::Builtin
    include Contracts::Core

    Contract String, Maybe[Integer], Func[Any => Any] => Any
    def self.contract_foo(a, b=nil, &blk)
      puts [a, b, blk].to_json
    end
  end

[26] development (main)> Bar.contract_foo "a" do
[26] development (main)* end
ParamContractError: Contract violation for argument 2 of 2:
        Expected: (Integer or nil),
        Actual: #<Proc:0x0055dbc44fc388@(pry):31>

[indigoviolet]

See #214

[egonSchiele]

I can reproduce