CSX - using custom attributes can give false error messages in the editor in some cases

[ZurielCorrea]

Steps to reproduce:
Create a new csx In VSCode with something similar to the following code:
#r "MyCustomAssembly.dll"

[MyCustomAttribute]
string myField;

Actual result:
The editor shows that "MyCustomAttribute" is incorrect, error message:"The type 'Attribute' is defined in an assembly that is not referenced. You must add a reference to assembly 'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'."

Expected result:
No errors are shown on the editor.

---

Note that creating an instance of the attribute like "var x = new MyCustomAttribute" does not show any errors.

Note that intellisense doesn't show you the parameters in the custom attribute, will specify this bug in another entry.

Note that the editor works as expected with system attributes.

version: Omnisharp-roslyn-dev from Today (Dec 5 2016 US EST)

[filipw]

thanks, will have a look