I'm getting an error on:

Roslyn Ref Source can't find it either: http://source.roslyn.codeplex.com/#Microsoft.CodeAnalysis.EditorFeatures/Implementation/Suggestions/SuggestedActionWithFlavors.cs,15

I'm guessing ISuggestedActionWithFlavors likely exists in a closed source component of the codebase.