disnet/contracts.js — pull request #7 by TobiaszCudnik (2012-03-11 22:14:36+00:00)
Title: getOwnPropertyDescriptor issues with null

getOwnPropertyDescriptor had some issues with null values, reproducible with following test case:
```coffeescript
a :: ({a: Str, b: Str}?) -> Any
a = (b) ->
console.log b
a null
```

There is more issues with this function, but i can't extract the code to reproduce.