Render error in Azure

[peter3]

After deploying to Azure the other day we got the following error on our site:

Message: D:\home\site\wwwroot\Areas\XXXX\Views\Blocks\SomeBlock.cshtml(15): error CS1061: 'string' does not contain a definition for 'ToHtmlString' and no extension method 'ToHtmlString' accepting a first argument of type 'string' could be found (are you missing a using directive or an assembly reference?)

Failed method: StackExchange.Profiling.Mvc.WrappedView.Render

We don't have any ToHtmlString in the view (and actually we don't use it anywhere).

Stack trace:

System.Web.HttpCompileException:
  at System.Web.Compilation.BuildManager.PostProcessFoundBuildResult (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
  at System.Web.Compilation.BuildManager.GetBuildResultFromCacheInternal (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a)
  at System.Web.Compilation.BuildManager.GetVPathBuildResultFromCacheInternal (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a) 
  at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a) 
  at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a) 
  at System.Web.Compilation.BuildManager.GetVirtualPathObjectFactory (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a) 
  at System.Web.Compilation.BuildManager.GetCompiledType (System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a) 
  at System.Web.Mvc.BuildManagerCompiledView.Render (System.Web.Mvc, Version=5.2.7.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35) 
  at StackExchange.Profiling.Mvc.WrappedView.Render (MiniProfiler.Mvc5, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b44f9351044011a3: C:\projects\dotnet\src\MiniProfiler.Mvc5\WrappedView.cs:55) 
  at System.Web.Mvc.ViewResultBase.ExecuteResult (System.Web.Mvc, Version=5.2.7.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35) 

Any suggestion what can have casued this error? A subsequent deploy without any changes to the view or the MiniProfiler code does not cause the error

Thanks

[peter3]

I forgot to mention: we have used MiniProfiler for at least a couple of months with frequent deploys without any issues until this particular deploy

[NickCraver]

.ToHtmlString() is from the base Mvc framework - it's likely a DLL didn't copy (maybe it was in use during deploy?) or similar. If you only saw it this one time, I wouldn't spend a lot more time investigating if it were me - but if it repeats you likely have some deploy contention/locking happening would be my first guess.