dotnet/roslyn

InvalidOperationException when showing parameters in Immediate window

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#31,180 建立於 2018年11月14日

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 (1 留言) (0 反應) (0 負責人)C# (20,414 star) (4,257 fork)batch import
Area-InteractiveBugInteractive-Debugginghelp wanted

描述

Version Used: VisualStudio.15.Preview/15.9.0-pre.6.0+28307.53

During a paused debugging session, in the Immediate window I tried to press Ctrl+K, P (show parameter info) on one of the lines I excuted earlier. I was presented with ActivityLog.xml error:

System.InvalidOperationException: Nullable object must have a value.
at System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource)
at Microsoft.CodeAnalysis.Editor.Implementation.IntelliSense.SignatureHelp.Controller.Session.ComputeModel(ImmutableArray`1 providers, SignatureHelpTriggerInfo triggerInfo)
at Microsoft.CodeAnalysis.Editor.Implementation.IntelliSense.SignatureHelp.Controller.StartSession(ImmutableArray`1 providers, SignatureHelpTriggerInfo triggerInfo)
at Microsoft.CodeAnalysis.Editor.Implementation.IntelliSense.SignatureHelp.Controller.Microsoft.VisualStudio.Commanding.IChainedCommandHandler<Microsoft.VisualStudio.Text.Editor.Commanding.Commands.InvokeSignatureHelpCommandArgs>.ExecuteCommand(InvokeSignatureHelpCommandArgs args, Action nextHandler, CommandExecutionContext context)
at Microsoft.VisualStudio.Commanding.CommandHandlerExtensions.ExecuteCommand[T](ICommandHandler commandHandler, T args, Action nextCommandHandler, CommandExecutionContext executionContext)
at Microsoft.CodeAnalysis.Editor.CommandHandlers.SignatureHelpCommandHandler.ExecuteCommandWorker[TCommandArgs](TCommandArgs args, Action nextHandler, CommandExecutionContext context)
at Microsoft.CodeAnalysis.Editor.CommandHandlers.SignatureHelpCommandHandler.Microsoft.VisualStudio.Commanding.IChainedCommandHandler<Microsoft.VisualStudio.Text.Editor.Commanding.Commands.InvokeSignatureHelpCommandArgs>.ExecuteCommand(InvokeSignatureHelpCommandArgs args, Action nextHandler, CommandExecutionContext context)
at Microsoft.VisualStudio.Commanding.CommandHandlerExtensions.ExecuteCommand[T](ICommandHandler commandHandler, T args, Action nextCommandHandler, CommandExecutionContext executionContext)
at Microsoft.VisualStudio.UI.Text.Commanding.Implementation.EditorCommandHandlerService.<>c__DisplayClass14_1`1.<Execute>b__1()
at Microsoft.VisualStudio.Text.Utilities.GuardedOperations.CallExtensionPoint(Object errorSource, Action call, Predicate`1 exceptionFilter)

貢獻者指南

技術棧
csharp
領域
developer experiencetooling
議題類型
bug
難度面向新貢獻者的預計實作難度，1 表示很小改動，5 表示專家級工作。
4
預計時間有經驗貢獻者完成調查、實作、測試並準備 pull request 的粗略時間範圍。
1-2 days
活動狀態議題目前的可參與程度：新鮮、活躍、陳舊、阻塞或等待維護者輸入。
stale
清晰度議題是否清楚說明預期改動、驗收標準和下一步。
clear
前置要求
Understanding of Roslyn's signature help internalsC# debugging experienceFamiliarity with Immediate window
新手友善度1-100 的估計分數，表示該議題對首次貢獻者的友善程度。
15
研究方向
The bug occurs in `Microsoft.CodeAnalysis.Editor.Implementation.IntelliSense.SignatureHelp.Controller` when computing the model during `InvokeSignatureHelpCommand`. The stack trace points to a `Nullable` value having no value, likely in a call to `.Value` on a nullable type. To fix, locate where in the `ComputeModel` or `StartSession` methods a nullable is assumed non null. Check the `SignatureHelpTriggerInfo` and the providers list for potential null source. The issue is old (2018) and has no activity, so it's likely low hanging but requires familiarity with the Roslyn codebase.