Steps to reproduce :

- import the project attached
- open the NewBehaviourScript.cs
- place a breakpoint in the line within Update()
- attach the debugger to Unity
- switch back to Unity and load the test scene
- copy gameObject.GetComponents<NewBehaviourScript>().ToList()
- go to Run > Expression Evaluator
- copy paste gameObject.GetComponents<NewBehaviourScript>().ToList()
- press evaluate and notice that Unity has crashed in the background

Duplicate :
http://issuetracker.unity3d.com/issues/editor-crash-during-adding-watch-item