This is a [known bug in Roslyn](https://github.com/dotnet/roslyn/issues/24978).  This bug will affect any version of Visual Studio that uses Roslyn.

If I am interpreting [VersionOf.net](https://versionof.net) correctly, the first version of Visual Studio with Roslyn built-in is 2015.  Before then, I *think* it was available only as an extension.  So, Visual Studio 2013 and prior should be unaffected.

It&#39;s due to be fixed in the [milestone 16 release](https://github.com/dotnet/roslyn/milestone/18).  At this time, that release is not scheduled.

Because this is a bug in Roslyn, you can &quot;get around&quot; it by editing and compiling the code containing the `unsafe struct` in an older version of Visual Studio, one that predates Roslyn.  Visual Studio 2012 should work.  You can then use the resultant .DLL in your current software.

An unverified fix is available if you build Roslyn yourself from [this branch](https://github.com/jcouv/roslyn/tree/verify-overflow).  The fix was made in [this commit](https://github.com/jcouv/roslyn/commit/0ada9b319ea8c74eb5cf9df60b1337012941f7ef).  


I&#39;m newbie to Firestore. Firestore docs says...

&gt; **Important**: Unlike &quot;push IDs&quot; in the Firebase Realtime Database, Cloud Firestore auto-generated IDs do not provide any automatic ordering. If you want to be able to order your documents by creation date, **you should store a timestamp as a field in the documents.**

Reference: https://firebase.google.com/docs/firestore/manage-data/add-data

So do I have to create key name as `timestamp` in document? Or `created` is suffice to fulfill above statement from Firestore documentation.

    {
    	&quot;created&quot;: 1534183990,
    	&quot;modified&quot;: 1534183990,
    	&quot;timestamp&quot;:1534183990
    }

Add timestamp in Firestore documents

This probably isn&#39;t a VS Code-specific question but it&#39;s my tool of choice. 

I have a log file with a lot of lines containing the following:

`Company.Environment.Security.RightsBased.Policies.RightsUserAuthorizationPolicy`

Those are debug-level log records that clutter the file I&#39;m trying to process.  I&#39;m looking to remove the lines with that content. 

I&#39;ve looked into Regex but, unlike removing a blank line where you have the whole content in the search criteria (making find/replace easy), here I need to match from line break to line break on some criteria between the two, I think...

What are your thoughts on how criteria like that would work?

Visual Studio Code - Removing Lines Containing criteria

For some reason, even so much as typing this into a C# file in Visual Studio is enough to cause it to instantly crash. Why?

    unsafe struct node {
        node*[] child;
    }

It seems to occur when the IDE would start coloring keywords and the like.

Trying it in TIO spits out `csc.exe exited with code 1` which isn&#39;t very helpful.

While array declarations in C# are different than in C/C++, the above &lt;i&gt;seems&lt;/i&gt; like it should be perfectly valid. Why isn&#39;t it, and why does it crash Visual Studio?

My Visual Studio version is 14.0.23107.

Why does this code crash Visual Studio 2015?

For some reason, even so much as typing this into a C# file in Visual Studio is enough to cause it to instantly crash. Why?
<pre><code class="hljs language-csharp">unsafe struct node {
 node*[] child;
}
</code></pre>
It seems to occur when the IDE would start coloring keywords and the like.
Trying it in TIO spits out <code>csc.exe exited with code 1</code> which isn't very helpful.
While array declarations in C# are different than in C/C++, the above seems like it should be perfectly valid. Why isn't it, and why does it crash Visual Studio?
My Visual Studio version is 14.0.23107.

Solution has compiled successfully, but after I added an existing class file to the project, this error appeared:

&gt; The specified task executable &quot;csc.exe&quot; could not be run. Could not
&gt; load file or assembly &#39;System.Security.Principal.Windows,
&gt; Version=4.0.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a&#39; or
&gt; one of its dependencies. The system cannot find the file
&gt; specified.	MvcApplicationRegister

I installed `System.Security.Principal.Windows` package By NuGet, but error still appears.		


Could not load file or assembly &#39;System.Security.Principal.Windows&#39;

When I updated Visual Studio to the latest version, 1 of my test projects stopped running tests and outputted this message:

&gt; Test project {} does not reference any .NET NuGet adapter. Test
&gt; discovery or execution might not work for this project. It is
&gt; recommended to reference NuGet test adapters in each test project in
&gt; the solution.

UPDATED: I was using MS Test as opposed to any other test frameworks like Nunit or Xunit.

Visual Studio 15.8.1 not running MS unit tests

I am trying to use HttpClient in my .net core 2.0 project and for that I have injected HttpClient in my controller. But when I am trying to configure httpclient in my startup.cs I am getting this error: &quot;IServiceCollection does not contain a defintion for AddHttpClient&quot;. I have already referenced `using Microsoft.AspNetCore.Http;` and `using Microsoft.Extensions.DependencyInjection;` and here is what I am trying to do: 

    services.AddHttpClient&lt;TestController&gt;();

It&#39;s working fine in other project with same namespaces but here I am getting the error. Any help?

IServiceCollection does not contain a defintion for AddHttpClient

I am trying to inject dependency into my middleware constructor as follows

    public class CreateCompanyMiddleware
	{
	    private readonly RequestDelegate _next;
	    private readonly UserManager&lt;ApplicationUser&gt; _userManager;

	    public CreateCompanyMiddleware(RequestDelegate next
	        , UserManager&lt;ApplicationUser&gt; userManager
	        )
	    {
	        _next = next;
	    }

	    public async Task Invoke(HttpContext context)
	    {
	        await _next.Invoke(context);
	    }
	}

My Startup.cs file looks like

	public void ConfigureServices(IServiceCollection services)
    {
        services.AddDbContext&lt;ApplicationDbContext&gt;(options =&gt;
            options.UseMySql(Configuration.GetConnectionString(&quot;IdentityConnection&quot;)));

        services.AddIdentity&lt;ApplicationUser, IdentityRole&gt;()
            .AddEntityFrameworkStores&lt;ApplicationDbContext&gt;()
            .AddDefaultTokenProviders();
        ...

        app.UseMiddleware&lt;CreateCompanyMiddleware&gt;();

        ...

But I am getting this error

&gt; An error occurred while starting the application.
InvalidOperationException: Cannot resolve scoped service &#39;Microsoft.AspNetCore.Identity.UserManager`1[Common.Models.ApplicationUser]&#39; from root provider.
Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteValidator.ValidateResolution(Type serviceType, IServiceScope scope, IServiceScope rootScope)

How to do DI in asp.net core middleware?

I have 2 projects in my solution, I have a project with Entity Framework Core installed:

[![enter image description here][1]][1]

And in the other ASP.NET Web API project I have these packages:

    &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
    &lt;packages&gt;
      &lt;package id=&quot;Antlr&quot; version=&quot;3.5.0.2&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;Microsoft.ApplicationInsights&quot; version=&quot;2.5.1&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;Microsoft.ApplicationInsights.Agent.Intercept&quot; version=&quot;2.4.0&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;Microsoft.ApplicationInsights.DependencyCollector&quot; version=&quot;2.5.1&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;Microsoft.ApplicationInsights.PerfCounterCollector&quot; version=&quot;2.5.1&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;Microsoft.ApplicationInsights.Web&quot; version=&quot;2.5.1&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;Microsoft.ApplicationInsights.WindowsServer&quot; version=&quot;2.5.1&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel&quot; version=&quot;2.5.1&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;Microsoft.AspNet.Mvc&quot; version=&quot;5.2.4&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;Microsoft.AspNet.Razor&quot; version=&quot;3.2.4&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;Microsoft.AspNet.TelemetryCorrelation&quot; version=&quot;1.0.0&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;Microsoft.AspNet.Web.Optimization&quot; version=&quot;1.1.3&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;Microsoft.AspNet.WebApi&quot; version=&quot;5.2.4&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;Microsoft.AspNet.WebApi.Client&quot; version=&quot;5.2.4&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;Microsoft.AspNet.WebApi.Core&quot; version=&quot;5.2.4&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;Microsoft.AspNet.WebApi.HelpPage&quot; version=&quot;5.2.4&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;Microsoft.AspNet.WebApi.WebHost&quot; version=&quot;5.2.4&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;Microsoft.AspNet.WebPages&quot; version=&quot;3.2.4&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;Microsoft.CodeDom.Providers.DotNetCompilerPlatform&quot; version=&quot;2.0.0&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;Microsoft.Web.Infrastructure&quot; version=&quot;1.0.0.0&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;Newtonsoft.Json&quot; version=&quot;11.0.1&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;System.Diagnostics.DiagnosticSource&quot; version=&quot;4.4.1&quot; targetFramework=&quot;net461&quot; /&gt;
      &lt;package id=&quot;WebGrease&quot; version=&quot;1.6.0&quot; targetFramework=&quot;net461&quot; /&gt;
    &lt;/packages&gt;

When I run `Add-Migration` in PMC:

&gt; Your startup project &#39;API&#39; doesn&#39;t reference
&gt; Microsoft.EntityFrameworkCore.Design. This package is required for the
&gt; Entity Framework Core Tools to work. Ensure your startup project is
&gt; correct, install the package, and try again.

I installed Microsoft.EntityFrameworkCore.Design in the startup project instead of the data project that will contain all the entities and now it works, is this how the project should be setup?

  [1]: https://i.stack.imgur.com/p3cQA.png

Your startup project doesn&#39;t reference Microsoft.EntityFrameworkCore.Design

I accidentally wrote 

    std::set&lt;string&gt; keys;

as:

    std:set&lt;string&gt; keys;

but weirdly enough, Visual Studio 2013 still compiles. 

Why does this happen? 

Actually `keys` is not only defined, but later used as a set of strings, such as

    if(keys.find(keystr)==keys.end()){
    	keys.insert(keystr);
    	toret.push_back(tempv);
    }

Why can std:set (with a single colon) compile?

I&#39;m attempting to build my first F# Android project in Visual Studio 2017 *(Community Edition)*.

Immediately after creating a new project by using the F# - Android - Blank App template, the error window in Visual Studio displays the following message:

&gt; The project Foo is missing Android SDKs required for building. Double-click on this message and follow the prompts to install them.

No amount of double-clicking on the message causes prompts to appear.

I can&#39;t find an obvious place to download the Android SDK from:

The SDK manager that I remember from a while ago seems to have disappeared from the Android developer website.

I&#39;ve installed Android Studio, which seemed to download some Android SDKs, but Visual Studio still can&#39;t seem to find whatever it&#39;s looking for.

The project is missing Android SDKs required for building

Previously, I was able to select the .NET Core 2.2 Framework in the properties section of the .NET Core project, but after the latest visual studio updates I haven&#39;t been able to. 


[![Framework Selection][1]][1]

Things I&#39;ve tried:

 - Repairing the .NET Core 2.2 SDK installation
 - Uninstalling and Reinstalling the .NET Core 2.2 SDK
 - Restarting Visual Studio
 - Restarting my machine
 - Making a fresh .NET Core project

Nothing has been able to work. From the fact that it was working before I installed the latest updates, could it just be a bug? Or is there something that I&#39;m missing? 

For some more clarity, I&#39;m running in Windows 10 Professional x64 on the latest version of windows. 

I installed this version of .NET Core 2.2 [from here][2] 

[![enter image description here][3]][3]

Any help is appreciated. Thanks!


  [1]: https://i.stack.imgur.com/qKU8w.png
  [2]: https://www.microsoft.com/net/download/dotnet-core/2.2
  [3]: https://i.stack.imgur.com/TIhxO.png

Content Type	Original Author	Original Content on Stackoverflow
Question	Orion	View Question on Stackoverflow
Solution 1 - C#	user47589	View Answer on Stackoverflow

Why does this code crash Visual Studio 2015?

C# Problem Overview

C# Solutions

Solution 1 - C#

Visual Studio Code - Removing Lines Containing criteria

Add timestamp in Firestore documents

Attributions