Shader forge produces errors

Not sure if this is intentional or not. I could see it being a feature, to let you know that your node graph is incorrect.

Here is the example I have used to produce a shader with errors:

Lerp (Vector4, Normal Vect., [null]) => Diffuse

It seems as though leaving out an interpolation value for the lerp should default to 0. I sometimes do this in other shader editors to cancel out functionality quickly for testing or debugging.