I want to use C# 6 in my project (null propagation, other features).
I've installed VS 2015 on my PC and it works brilliantly and builds test code like
var user = new SingleUserModel(); //all model fields are null
var test = user.User?.Avatar?["blah"];
But when I push my project to the repo and CI starts to build it, build fails because of unsupported ?.
I've installed VS2015 on CI server too but looke like it doesn't use it.
What can I do?
CI - CruiseControl .NET
Builds with C:\Windows\Microsoft.NET\Framework\v4.0.30319\MSBuild.exe
Make sure you call:
C:\Program Files (x86)\MSBuild\14.0\Bin\MsBuild.exe
That's the version of MsBuild that ships with Visual Studio 2015 and calls the C# compiler that understands this. You can get this version of MsBuild on your system by installing any edition of Visual Studio 2015 or by installing the stand-alone Microsoft Build Tools 2015.
Adding a reference to the following NuGet package will also force use of the new compiler:
Install-Package Microsoft.Net.Compilers
Please note Install-Package will pick the latest available version which may not be the one you are looking for. Before you install, please check the release notes and dependencies to resolve the underlying issue with the version being dealt with, which in this case, was more specific to VS 2015.
So for Visual Studio 2015:
Install-Package Microsoft.Net.Compilers -Version 1.0.0
You can by the way also install the "Microsoft Build Tools 2015" instead of VS2015 on your build server.
https://www.microsoft.com/en-us/download/details.aspx?id=48159
It installs MSBuild to the same path:
C:\Program Files (x86)\MSBuild\14.0\Bin\MsBuild.exe
You probably already have this working, but this might help someone else in the future. I came across this question recently and it got me moving in the right direction and ultimately led to a solution.
Another possible solution to this is manually updating your project files to target the MSBuild version you want your projects to be built with.
I've recently gone through a TeamCity build server update and I've already installed the Microsoft Build Tools 2015 on it. I thought I had everything in place on the build server, I had my solution targeting C# 6.0, and I had every project targeting .net 4.6.1. Like you, everything with C# 6.0-specific code built just fine in my local environment, but my TeamCity build server didn't like any of it.
As mentioned by others, I tried using the Microsoft.Net.Compilers NuGet package. The latest version of it allowed the build to work on my build server, but it wouldn't let me publish my code locally (a requirement of mine). Earlier versions of that NuGet package would let me publish, but the build wouldn't work.
What I found that I had to do was ultimately modify each project file in my solution to specifically target the MSBuild version that could handle C# 6.0 code. In each of my project files, I found a line similar to the following line:
<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
with the key component of that line being the ToolsVersion portion of it. I simply changed this line on my project files to read the following:
<Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
The difference here was that I was targeting version 14, not 4. Version 14.0 corresponds with Build Tools 2015. By changing this, my TeamCity build server used the correct MSBuild version and was able to build my C# 6.0 code.
I also had to manually update the TargetFrameworkVersion xml node of this to use 4.6.1 because VS2015 wasn't doing something right and messed up my local build, but that's not relevant here.
Please, someone correct me if I'm wrong, but just for reference, I think the version numbers go something like this:
4.0 = VS2012
12.0 = VS2013
14.0 = VS2015
15.0 = VS2017
I believe if you wanted to use .net 4.7, you'd have to have the Build Tools 2017 installed and have your projects targeting 15.0 instead of 14.0, but I haven't verified this.
Related
I have made a project in VS2019. I have the same project in .NET Core and .NET Framework. I use a COM reference in my project. I would like to migrate these projects to Pi4.
A simple Hello World project (.NET Core) is running successfully on the Pi4 machine. However, when I try to run my project (.NET core or .NET Framework) it does not run on the Pi4. It says COM is not supported.
I tried to build the project using MSBuild in my Windows environment after looking for solutions in Google. I also see a similar error here. The error is: error : MSB4803: The task "ResolveComReference" is not supported on the .NET Core version of MSBuild. Please use the .NET Framework version of MSBuild.
The .NET Framework project also gives a similar error.
error MSB4028: The "ResolveComReference" task's outputs could not be retrieved from the "ResolvedFiles" parameter. Object does not match target type.
Does anyone have similar issues?
https://github.com/microsoft/msbuild/issues/3986
According to the above link. The employee of Microsoft is saying they can not give solution in the near future.
Set the Projects to x86 for them to build the Interop, the Interop created still could not be used in x64 runtimes.
Add the COM Reference to the Core project, Build it and you will get an Interop.YourCom in the bin/x86/core/debug folder.
Remove the COM reference, and re-add the Interop, it will be put into the Assemblies Dependencies, and MSBuild will work.
My MSB4803 was from a WIXInstaller project, for ADOX, and Microsoft.Office.Interop.Access.Dao
I stumbled upon this question many times and I experienced the same several times in different projects. It doesn't matter if it is Visual Studio 2019 or 2022 and the version of the build, unless you are working with the old MSBuild in a legacy environment, the COM Reference doesn't work. It is always safe to build it in the command line to understand if anything in the VS environment works. I don't truly understand why Microsoft let you make those references in the Visual Studio environment when they will not work nearly anywhere else.
There are some workarounds that might or might not work but if your code is already pointing at a COM library there is no much to do. You can install the NuGet package which is going to pass the build stage and remove the COM reference.
Install-Package Microsoft.Office.Interop.Excel -Version 15.0.4795.1001
The NuGet package has some differences at the types level that you will need to fix (the COM reference allows you to get specific types instead of objects from the cells values)
In any case, you will need the COM installed in the server, there is no workaround that issue.
I wouldn't say I like this error message or the link it shows on how to fix it, to be polite.... ;-);
I figured it out and thought as there are a lot of answers that are not helpful to share mine. What I did is update your command to force the use of msbuild.
dotnet msbuild -v:normal "FullOrRelativePathTo\MyProject.csproj" -p:Configuration=RELEASE
If that fails, try:
"C:\Program Files\Microsoft Visual Studio\2022\Enterprise\MSBuild\Current\Bin\msbuild.exe" "PathTo\Project.csproj" /p:Configuration=RELEASE
I know I'm late to the party, but here is a workaround working for me when I want to use Office Interop in .NET (Core):
Create an empty .net Console app (I'm using Rider and .NET 7)
Build it with the default MSBuild (17.0 in my case at the time of writing)
Add Interop references to the project file (I don't use Nuget, only generate these in a dummy .NET Framework project while adding COM references to Office libraries), eg.
<ItemGroup>
<COMReference Include="Excel">
<Guid>{00020813-0000-0000-C000-000000000046}</Guid>
<VersionMajor>1</VersionMajor>
<VersionMinor>9</VersionMinor>
<Lcid>0</Lcid>
<WrapperTool>tlbimp</WrapperTool>
<Isolated>False</Isolated>
<EmbedInteropTypes>True</EmbedInteropTypes>
</COMReference>
</ItemGroup>
Change the solution MSBuild version to 4.0
Try to build the solution, but the project will not even load properly due to an outdated MSBuild version
Revert the MSBuild version to the default one
Build the project - success! (this is the magic part, I can't explain it :P)
We have a Visual Studio 2013 project who's .csproj looks like this
<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
Recently we migrated the solution to Visual Studio 2017 but somehow tool version remained same.
I am using TeamCity to build my project & on teamcity server we only have MS build version 14. If I use it to build the app, I get following error: The imported project "C:\Program Files (x86)\MSBuild\Microsoft\VisualStudio\v11.0\WebApplications\Microsoft.WebApplication.targets" was not found. Confirm that the path in the <Import> declaration is correct, and that the file exists on disk.
What is the easiest way to update the tool-version is .csproj? If I update it manually, would it cause any issues? are there any other settings/config I need to change once I make this change?
ToolsVersion is not the main cause of this issue I think, so you can feel free to manually change it. And for project from VS2013, its ToolsVersion should be 12.0 instead of 4.0.
VS2013=>12.0, VS2017=>15.0, VS2015=>14.0: So you now have one project migrated from VS2012 to VS2017, and now you use msbuild of VS2015 to build it. For this scenario, here're some suggestions which may help:
1.Change the ToolsVersion to 12.0(or 14.0). This actually makes a bit effect.
2.Make sure you've installed web application workload for your msbuild 14.0 in server. If your msbuild 14.0 comes from VS2015, please check if you can create new web application project in it, then you'll know if you've installed web workload in VS! (The missing targets come from the web app workload, similar issue see here.)
If you can find the missing file in C:\Program Files (x86)\MSBuild\Microsoft\VisualStudio\v14.0\WebApplications, trying passing /p:VisualStudioVersion=14.0 to msbuild command when you configure it in teamcity.
3.The most recommended way is to install the msbuild from higher VS version. MSbuild has independent package for VS2017 and VS2019.(Build Tools for VS2017 or VS2019)
You can find their download link here,see Tools for VS category. You can install this package(Enable web-related workload!) in your server(you don't need to install whole VS IDE), and then you can call msbuild.exe from C:\Program Files (x86)\Microsoft Visual Studio\2019\BuildTools\MSBuild\Current\Bin or C:\Program Files (x86)\Microsoft Visual Studio\2017\BuildTools\MSBuild\15.0\Bin in teamcity to build current project.
Note: MSBuild from higher VS version can always build projects from earlier VS versions, but msbuild from earlier sometimes can't recognize projects from higher vs versions. So it's recommended to use msbuild 15.0 to build projects from VS2017, instead of using msbuild 14.0.
I have a UWP project that was created using Visual Studio 2017. It builds fine on this machine (machine 1).
However, when I copy the project over to a machine (machine 2) where I only have the Visual Studio 2017 Build Tools installed, and attempt to build it using MSBuild, I get the following error:
C:\Program Files (x86)\Microsoft Visual Studio\2017\BuildTools\MSBuild\15.0\Bin\Microsoft.Common.CurrentVersion.targets
(1126,5): error MSB3644: The reference assemblies for framework ".NETCore,Version=v5.0" were not found. To resolve this
, install the SDK or Targeting Pack for this framework version or retarget your application to a version of the framewo
rk for which you have the SDK or Targeting Pack installed. Note that assemblies will be resolved from the Global Assemb
ly Cache (GAC) and will be used in place of reference assemblies. Therefore your assembly may not be correctly targeted
for the framework you intend. [<path_to_my_UWP_project>\UWP.csproj]
I suspect the need for .NetCore v5.0 arises from this line in my UWP.csproj file:
< PackageReference
Include="Microsoft.NETCore.UniversalWindowsPlatform" Version="6.0.1"
/>
I do a nuget restore before I build on machine 2, and I can see that microsoft.netcore.universalwindowsplatform successfully gets restored under < C_Users_me >/.nuget/packages, and so does microsoft.netcore.
On machine 1 however, only microsoft.netcore.universalwindowsplatform gets restored but it still builds fine via Visual Studio.
Question: Why am I getting this error and how do I fix the problem?
I was getting the same error message. The resolution was to install the latest version of Visual Studio 2019. I had version 16.6 installed on my computer. I needed version 16.8 installed. Once I did the install, the error message went away.
Initial reason for this issue: I had received a VS C# solution from another individual. Apparently there was something in the solution that stated it required some library (.NETFramework v=5.0) which was not in 16.4 but was in 16.8.
The help instructions on the VS error message did not help; there is currently no .NETFramework, version=v5.0. There is only a .NET Core Version=5.0 or a .NetFramework Version=v4.8
This gitHub post lead me to the correct soltuion.
I was chasing the exact same issue but for all I could see, I had the right SDK installed. As it turned out, I had caused the issue myself by placing a global.json in the root directory with the SDK version pinned to 3.1.404.
dotnet was honouring the global.json settings and hence could not locate the reference assemblies for 5.0.
Removing the global.json fixed the issue for me.
You need to use Visual Studio 2019 16.8 Preview 2 or newer to use .NET 5 Preview 8. .NET 5 Download it here https://learn.microsoft.com/en-us/visualstudio/releases/2019/release-notes-preview
The reference assemblies for framework .NETCore, Version=v5.0 were not found
According to the error log, it seems you are missing the .NET framework SDK (. NET core, v5.0) on your machine 2. You can check the it from following directory:
C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETCore\v5.0
To install it, make sure you are install following individual components:
If you still have that error, please try to copy the directory C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETCore\v5.0 from machine 1 to machine 2.
Hope this helps.
The below steps worked for me.
In Visual Studio open View -> Terminal and enter: dotnet new global.json
Open the root folder of the solution and edit the newly created file "global.json" the exact name of the .net version installed must be entered.
To view all installed .net core sdk's , enter dotnet --list-sdks in command.
add the correct version to the global.json file, the right-click solution, and select Restore Nuget Packages or restart the visual studio.
The global.json will look like this
See you have Microsoft Visual Studio v16.8 or above.
To update the VS version -> Help -> Check for Updates
This error is displayed if the .NET 5.0 SDK is not installed. Be careful, you must download the proper sdk:
dotnet-sdk-5.0.401-win-x64.exe or dotnet-sdk-5.0.401-win-x86.exe depending on your installation (in the case of Visual Studio Code or your Windows) In the path https: // dotnet.microsoft.com/download/dotnet/5.0 you can download.
I had the same error message
enter image description here
1- Open Visual Studio Installer
2- Updat the version of Visual Studio 2019 to 16.11 or Upper
3- Restart your Project
I'm trying to build a solution using msbuild command line and I keep getting this error:
error MSB4236: The SDK 'Microsoft.NET.Sdk' specified could not be found.
The version of msbuild is the latest from microsoft visual studio 2017 tools. I'm using Windows Server 2012 R2 and the project uses .NET Core 2.0.
This is the command that I'm using:
msbuild.exe /p:Configuration=Release /t:restore C:\Projects\MyProject.sln
Complete log:
Microsoft (R) Build Engine version 15.3.409.57025 for .NET Framework
Copyright (C) Microsoft Corporation. All rights reserved.
Building the projects in this solution one at a time. To enable parallel build, please add the "/m" switch.
Build started 9/16/2017 3:09:03 PM.
Project "C:\Projects\MyProject.sln" on node 1 (restore target(s)).
ValidateSolutionConfiguration:
Building solution configuration "Release|Any CPU".
Project "C:\Projects\MyProject.sln" (1) is building "C:\Projects\Kernel\Kernel.csproj" (2) on node 1 (restore target(s)).
C:\Projects\MyProject.sln" (1) is building "C:\Projects\Kernel\Kernel.csproj : error MSB4236: The SDK 'Microsoft.NET.Sdk' specified could not be found.
Done Building Project "C:\Projects\MyProject.sln" (1) is building "C:\Projects\Kernel\Kernel.csproj" (restore target(s)) -- FAILED.
Build FAILED.
"C:\Projects\MyProject.sln" (restore target) (1) ->
"C:\Projects\Kernel\Kernel.csproj" (restore target) (2) ->
C:\Projects\Kernel\Kernel.csproj : error MSB4236: The SDK 'Microsoft.NET.Sdk' specified could not be found.
0 Warning(s)
11 Error(s)
I encountered this error after playing around with .Net Core 2.0 installation and seemingly messing it up. I would get this same error for dotnet restore, dotnet build or dotnet msbuild. Essentially, anything involving .Net Core and msbuild.
The error occurred because the MSBuildSDKsPath environment variable was still pointing to the old .Net Core 1.1 SDK.
To fix the problem, I manually set the MSBuildSDKsPath environment variable to point to 2.0.0's SDK path, which, for me with x64, this was at: C:\Program Files\dotnet\sdk\2.0.0\Sdks.
Basically, if you have Sdk="Microsoft.NET.Sdk" in your .csproj, then a folder with the same name should exist at your MSBuildSDKsPath location.
You were probably missing some components when you installed the VS tools
Download and run Build Tools for Visual Studio 2019. (On the VS download page, go to Tools for Visual Studio 2019 and then click download Build Tools for Visual Studio 2019)
Select Modify on Visual Studio Build Tools 2019 or your instance.
Select tab Individual components and check .NET Core SDK component
for me the solution was to set the sdk version in the global.json file:
and specify the correct version which exists in the C:\Program Files\dotnet\sdk folder. The VS installer uninstalled the previous version of .NET Core 3.0.100 and installed new one 3.1.100 so I had to change it from:
{ "sdk": { "version": "3.0.100" }}
to
{ "sdk": { "version": "3.1.100" }}
For me updating Visual Studio Build Tools resulted in the 'SDK not found' error.
The solution: run Visual Studio Installer, modify the Visual Studio (Build Tools) installation, and make sure the following workload is selected:
I got this issue in Mac OS and while using docker container and Azure this occurs because docker bash overrides MSBuildSDKsPath so don't
change any code just quit and restart your IDE (visual studio Mac) and run it again
I got the same issue when I tried to install x64 .Net Core SDK installer. Even the following dotnet --info command shows me that no SDK is found.
So, try to install x86 .Net Core SDK installer. That can help you.
I had the same problem and found solution here:
https://github.com/aspnet/AspNetCore/issues/3624
Solution is to just have x64 or x86 version of sdk/runtime/hosting.
If you have both and if you use for example x86 version of dotnet.exe it won't see x64 versions of SDK installed.
Problem usually occures when you install hosting bundle because it includes both x86 and x64. Just uninstall one you don't use.
To anyone that, like me, run into this issue on Linux and found this thread:
This problem occurs, because your .bashrc config overrides MSBuildSDKsPath environment variable with outdated value (most likely it's a leftover after dotnet package update). To solve this:
Edit ~/.bashrc
Remove the line with MSBuildSDKsPath variable initialization, e.g.
export MSBuildSDKsPath="/opt/dotnet/sdk/2.2.108/Sdks/"
If you have previously worked with C# and it somehow stopped working:
For me updating to the latest version (probably of the build tools) with the "Visual Studio Installer" solved the problem.
I started getting this error after installing Visual Studio 2022 in Windows 10, when I opened up my solution. The solution contains a mix of .NET Framework 4.8 and .NET Standard 2.0 projects, and the error was on the .NET Standard 2.0 projects. I had previously Visual Studio 2019 and 2019 Build Tools installed.
The problem was that I had both x86 and x64 of dotnet installed, and both was in my systems PATH environment variable:
C:\Program Files (x86)\dotnet
C:\Program Files\dotnet
I did the following steps to fix this error:
Uninstalled VS2019
Uninstalled VS2019 Build Tools
Removed the x86 path from the environment variable
Removed the folder "C:\Program Files (x86)\dotnet" from my computer
Restarted VS2022
I think that the important part was to remove x86 from the environment variable. The other steps was just to "clean up".
I resolve the issue by installing the package directly form the Package Manager Console:
Install-Package NETStandard.Library -Version 2.0.3
Maybe you encountered the error after installing .NET core SDK 3.0. You have to check the environment variable MSBuildSDKsPath after every install of a new SDK. It must target the SDK you use to create your project. I use VS2017 with Windows 10.
For 2.2 SDK:
C:\Program Files\dotnet\sdk\2.2.104\Sdks
For 3.0 preview :
C:\Program Files\dotnet\sdk\3.0.100-preview3-010431\Sdks
The issue was occuring for me only when I tried to build the project with
dotnet build using VS2022 .
MsBuild on the same project was working fine.
What I did was:
restore the .net core runtime sdk - I was using 3.1 at the time.
Add both sdk paths in both Path vars, for the user and system, in that order:
Delete the MSBuildSDKsPath
P.s. I had this error while trying to run the coverlet coverage analysis
Had the same issue after I updated (snip) all VS installations on my windows machine a while ago. A restart of my PC resolved the issue.
I had this same issue, and it turned out the resolution for me was none of the above for me.
I was running the VS preview version with an older version of VS. I removed the Preview VS and then had to remove each of the environment variables by hand (i.e ANDRIOD_HOME, and .Net Maui vars, etc) and was back in business. Hope this helps someone out there who has installed VS Preview only to break the dev build environment.
Cause I had a lot of diffeculties finding the url for build tools, here it is :
https://aka.ms/vs/16/release/vs_buildtools.exe
Documenantion :
https://learn.microsoft.com/en-us/visualstudio/install/create-an-offline-installation-of-visual-studio?view=vs-2019
I encountered the same error and to fix it I installed .NET 6.0 SDK.
https://dotnet.microsoft.com/en-us/download/visual-studio-sdks
I only had .NET 7.0 SDK installed, and for whatever reason the project I was trying to use needed .NET 6.0 SDK.
I ran into this issue after installing .NET 7 to work with gRPC. After uninstalling .NET 7 the IDE was still looking for it. I deleted the empty C:\Program Files\dotnet\sdk\7 folder. I closed an opened the project it found the lastest .NET 6 installation.
I was going through the latest features introduced in C# 6.0 and just followed an example of auto property initializer,
class NewSample
{
public Guid Id { get; } = Guid.NewGuid();
}
but my IDE did not recognize the syntax.
I am wondering how I could enable C# 6.0 in Visual Studio 2013. The Target framework I am using is 4.5.1.
Under VS2013 you can install the new compilers into the project as a nuget package. That way you don't need VS2015 or an updated build server.
https://www.nuget.org/packages/Microsoft.Net.Compilers/
Install-Package Microsoft.Net.Compilers
The package allows you to use/build C# 6.0 code/syntax. Because VS2013 doesn't natively recognize the new C# 6.0 syntax, it will show errors in the code editor window although it will build fine.
Using Resharper, you'll get squiggly lines on C# 6 features, but the bulb gives you the option to 'Enable C# 6.0 support for this project' (setting saved to .DotSettings).
As mentioned by #stimpy77: for support in MVC Razor views you'll need an extra package (for those that don't read the comments)
Install-Package Microsoft.CodeDom.Providers.DotNetCompilerPlatform
If you want full C# 6.0 support, you'll need to install VS2015.
Information for obsoleted prerelease software:
According to this it's just a install and go for Visual Studio 2013:
In fact, installing the C# 6.0 compiler from this release involves little more than installing a Visual Studio 2013 extension, which in turn updates the MSBuild target files.
So just get the files from https://github.com/dotnet/roslyn and you are ready to go.
You do have to know it is an outdated version of the specs implemented there, since they no longer update the package for Visual Studio 2013:
You can also try April's End User Preview, which installs on top of Visual Studio 2013.
(note: this VS 2013 preview is quite out of date, and is no longer updated)
So if you do want to use the latest version, you have to download the Visual Studio 2015.
A lot of the answers here were written prior to Roslyn (the open-source .NET C# and VB compilers) moving to .NET 4.6. So they won't help you if your project targets, say, 4.5.2 as mine did (inherited and can't be changed).
But you can grab a previous version of Roslyn from https://www.nuget.org/packages/Microsoft.Net.Compilers and install that instead of the latest version. I used 1.3.2. (I tried 2.0.1 - which appears to be the last version that runs on .NET 4.5 - but I couldn't get it to compile*.) Run this from the Package Manager console in VS 2013:
PM> Install-Package Microsoft.Net.Compilers -Version 1.3.2
Then restart Visual Studio. I had a couple of problems initially; you need to set the C# version back to default (C#6.0 doesn't appear in the version list but seems to have been made the default), then clean, save, restart VS and recompile.
Interestingly, I didn't have any IntelliSense errors due to the C#6.0 features used in the code (which were the reason for wanting C#6.0 in the first place).
* version 2.0.1 threw error The "Microsoft.CodeAnalysis.BuildTasks.Csc task could not be loaded from the assembly Microsoft.Build.Tasks.CodeAnalysis.dll. Could not load file or assembly 'Microsoft.Build.Utilities.Core, Version=14.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified. Confirm that the declaration is correct, that the assembly and all its dependencies are available, and that the task contains a public class that implements Microsoft.Build.Framework.ITask.
UPDATE One thing I've noticed since posting this answer is that if you change any code during debug ("Edit and Continue"), you'll like find that your C#6.0 code will suddenly show as errors in what seems to revert to a pre-C#6.0 environment. This requires a restart of your debug session. VERY annoying especially for web applications.
It worth mentioning that the build time will be increased for VS 2015 users after:
Install-Package Microsoft.Net.Compilers
Those who are using VS 2015 and have to keep this package in their projects can fix increased build time.
Edit file packages\Microsoft.Net.Compilers.1.2.2\build\Microsoft.Net.Compilers.props and clean it up. The file should look like:
<Project DefaultTargets="Build"
xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
</Project>
Doing so forces a project to be built as it was before adding Microsoft.Net.Compilers package
It is possible to use full C# 6.0 features in Visual Studio 2013 if you have Resharper.
You have to enable Resharper Build and voilá!
In Resharper Options -> Build - enable Resharper Build and in "Use MSBuild.exe version" choose "Latest Installed"
This way Resharper is going to build your C# 6.0 Projects and will also not underline C# 6.0 code as invalid.
I am also using this although I have Visual Studio 2015 because:
Unit Tests in Resharper don't work for me with Visual Studio 2015 for some reason
VS 2015 uses a lot more memory than VS 2013.
I am putting this here, as I was looking for a solution for this problem for some time now and maybe it will help someone else.
It seems there's some misunderstanding. So, instead of trying to patch VS2013 here's and answer from a Microsoft guy: https://social.msdn.microsoft.com/Forums/vstudio/en-US/49ba9a67-d26a-4b21-80ef-caeb081b878e/will-c-60-ever-be-supported-by-vs-2013?forum=roslyn
So, please, read it and install VS2015.