error MSB4017: The build stopped unexpectedly because of an unexpected logger failure.

[tmat]

Roslyn build failed on Mono on Linux in CI:
https://dnceng.visualstudio.com/public/_build/results?buildId=58826

2018-12-14T22:39:40.6224939Z MSBUILD : error MSB4017: The build stopped unexpectedly because of an unexpected logger failure.
2018-12-14T22:39:40.6286244Z Microsoft.Build.Exceptions.InternalLoggerException: The build stopped unexpectedly because of an unexpected logger failure. ---> System.NullReferenceException: Object reference not set to an instance of an object.
2018-12-14T22:39:40.6294193Z    at Microsoft.Build.Execution.ProjectItemInstance.TaskItem.CloneCustomMetadata()
2018-12-14T22:39:40.6299893Z    at Microsoft.Build.Logging.BuildEventArgsWriter.Write(ITaskItem item)
2018-12-14T22:39:40.6367163Z    at Microsoft.Build.Logging.BuildEventArgsWriter.WriteItemList(IEnumerable items)
2018-12-14T22:39:40.6407246Z    at Microsoft.Build.Logging.BuildEventArgsWriter.Write(TargetFinishedEventArgs e)
2018-12-14T22:39:40.6413023Z    at Microsoft.Build.Logging.BuildEventArgsWriter.Write(BuildEventArgs e)
2018-12-14T22:39:40.6418607Z    at Microsoft.Build.Logging.BinaryLogger.Write(BuildEventArgs e)
2018-12-14T22:39:40.6425793Z    at Microsoft.Build.Logging.BinaryLogger.EventSource_AnyEventRaised(Object sender, BuildEventArgs e)
2018-12-14T22:39:40.6431352Z    at Microsoft.Build.Evaluation.ProjectCollection.ReusableLogger.AnyEventRaisedHandler(Object sender, BuildEventArgs e)
2018-12-14T22:39:40.6436766Z    at Microsoft.Build.BackEnd.Logging.EventSourceSink.RaiseAnyEvent(Object sender, BuildEventArgs buildEvent)
2018-12-14T22:39:40.6445093Z    --- End of inner exception stack trace ---
2018-12-14T22:39:40.6450881Z    at Microsoft.Build.Exceptions.InternalLoggerException.Throw(Exception innerException, BuildEventArgs e, String messageResourceName, Boolean initializationException, String[] messageArgs)
2018-12-14T22:39:40.6458469Z    at Microsoft.Build.BackEnd.Logging.EventSourceSink.RaiseAnyEvent(Object sender, BuildEventArgs buildEvent)
2018-12-14T22:39:40.6464164Z    at Microsoft.Build.BackEnd.Logging.EventSourceSink.RaiseStatusEvent(Object sender, BuildStatusEventArgs buildEvent)
2018-12-14T22:39:40.6478370Z    at Microsoft.Build.BackEnd.Logging.EventSourceSink.RaiseTargetFinishedEvent(Object sender, TargetFinishedEventArgs buildEvent)
2018-12-14T22:39:40.6478500Z    at Microsoft.Build.BackEnd.Logging.EventSourceSink.Consume(BuildEventArgs buildEvent)
2018-12-14T22:39:40.6478595Z    at Microsoft.Build.BackEnd.Logging.EventSourceSink.Consume(BuildEventArgs buildEvent, Int32 sinkId)
2018-12-14T22:39:40.6478667Z    at Microsoft.Build.BackEnd.Logging.EventRedirectorToSink.Microsoft.Build.Framework.IEventRedirector.ForwardEvent(BuildEventArgs buildEvent)
2018-12-14T22:39:40.6478759Z    at Microsoft.Build.BackEnd.Logging.CentralForwardingLogger.EventSource_AnyEventRaised(Object sender, BuildEventArgs buildEvent)
2018-12-14T22:39:40.6478838Z    at Microsoft.Build.BackEnd.Logging.EventSourceSink.RaiseAnyEvent(Object sender, BuildEventArgs buildEvent)