Adding a Vector3 operation to the Visual Studio 2017 Watch window displays: "Node not supported: 'b - a' "

How to reproduce:
1. Open user attached project
2. Open Assets/Scene.unity
3. Open Assets/Scripts/TestCode.cs in Visual Studio
4. Add a Breakpoint at line 11 "Debug.LogFormat..."
5. Attach Visual Studio to Unity
6. In Unity, press Play
7. Visual Studio should now halt in TestCode.cs at line 11
8. In Visual Studio, open "Debug/Windows/Watch/Watch 1"
9. Add Vector3 a, b and c to Watch window
10. Observe each Vector3 can be visualized
11. Add "b - a" to Watch window
12. Observe the Watch window displays an error: Node not supported: 'b - a'

Expected result: VSTU should be able to evaluate/visualize Vector3 operations in the Watch window, as it is very common during development having the need to evaluate a math operation while debugging

Reproduced with:
Visual Studio: 2015, 2017;
Visual Studio Tools for Unity: 3.1.0.0;
Unity: 5.6.3f1, 2017.1.0p3, 2017.2.0b6, 2017.3.0a3