NullReferenceException: Object reference not set to an instance of an object
UnityEditor.Graphs.Edge.WakeUp () (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/Edge.cs:114)
UnityEditor.Graphs.Graph.DoWakeUpEdges (System.Collections.Generic.List`1 inEdges, System.Collections.Generic.List`1 ok, System.Collections.Generic.List`1 error, Boolean inEdgesUsedToBeValid) (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/Graph.cs:387)
UnityEditor.Graphs.Graph.WakeUpEdges (Boolean clearSlotEdges) (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/Graph.cs:286)
UnityEditor.Graphs.Graph.WakeUp (Boolean force) (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/Graph.cs:272)
UnityEditor.Graphs.Graph.WakeUp () (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/Graph.cs:250)
UnityEditor.Graphs.Graph.OnEnable () (at C:/buildslave/unity/build/Editor/Graphs/UnityEditor.Graphs/Graph.cs:245)

出现这个的原因未知(unity抽风),解决方法就是重启就好了(万能重启)