enforce extra type checks

[vans163]

[] |> :erlang.binary_to_integer
NaN

length(0)
undefined

We should crash here, given that is the behavior of elixir. I am sure there is many more like this.

[bryanjos]

I'm sure there are more too. Will probably have to investigate how each works. For some I tried to go by what the erlang docs said, but I think some of the crash scenarios may not be documented