如果在调试过程中更改代码（“编辑并继续”），然后执行Debug.SetNextStatement，则CLR崩溃

Question

During Visual Studio 2015 debugging session (breakpoint hit), if I change almost any code and select any of Continue , Step Into , Step Over (, etc.), commands, I immediately get ExecutionEngineException followed by CLR crash.

This seems to be appearing only in one project.

System.Windows.Forms.dll!System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(int dwComponentID, int reason, int pvLoopData)    Unknown
System.Windows.Forms.dll!System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(int reason, System.Windows.Forms.ApplicationContext context)    Unknown
System.Windows.Forms.dll!System.Windows.Forms.Application.ThreadContext.RunMessageLoop(int reason, System.Windows.Forms.ApplicationContext context) Unknown
System.Windows.Forms.dll!System.Windows.Forms.Application.Run(System.Windows.Forms.ApplicationContext context)  Unknown
Microsoft.VisualBasic.dll!Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.OnRun() Unknown
Microsoft.VisualBasic.dll!Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.DoApplicationModel()    Unknown
Microsoft.VisualBasic.dll!Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.Run(string[] commandLine)   Unknown
[Native to Managed Transition]  
[Managed to Native Transition]  
mscorlib.dll!System.AppDomain.ExecuteAssembly(string assemblyFile, System.Security.Policy.Evidence assemblySecurity, string[] args) Unknown
Microsoft.VisualStudio.HostingProcess.Utilities.dll!Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()   Unknown
mscorlib.dll!System.Threading.ThreadHelper.ThreadStart_Context(object state)    Unknown
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) Unknown
mscorlib.dll!System.Threading.ThreadHelper.ThreadStart()    Unknown

How to troubleshoot this issue?

Answer 1

I found the answer by minimalization of the problem scenario.

It looks that problem is with combination visual-studio-2015 + .net-3.5 + vb.net and this code:

Public Class Form1
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim gridSize As Size = New Size(3, 11)
        Dim z As Integer
        z = 22
        z = 1
    End Sub
End Class

Place breakpoint at End Sub , stop at it, swap the assignments and set next statement to the first assignment. Boom.

Reported to the Microsoft. Workaround is to use .net-4.0 and higher.

Answer 2

I have the same problem with Visual Studio Community 2015 in C#. When debugging a project compiled for .Net 3.5, hitting a breakpoint and doing 'edit and continue', it rarely survives. The compiler/IDE crashes with one of several possible error messages, most often with ExecutionEngineException followed by CLR crash.

When the same project is compiled to .net 4.6.1, the VS 2015 IDE debugger operates correctly. It is enough to set the main project to .net 4.6.1; the .dlls called are then debuggable even when they are still .net 3.5.

(The old VS 2013 IDE debugger operated correctly with .net 3.5, only very rarely it crashed.)

This behaviour is true for many projects.