title: Build error with code analyzer after upgrading to .net core 3.1 preview4
body: <p>I have a Blazor webassembly project (hosted) and I've just tried to upgrade it to the release version of .net core 3.1. To do this I have upgraded VS 2019 preview to 16.5 preview 1. I've upgraded all the packages in my project to 3.1.0-preview4.19579.2. I've also updated the client and shared projects to .net standard 2.1 and installed the latest templates (I think).</p>
  
  <p>When I try and build my solution I'm now getting this error which appears to show a duplicate code analysis resource file somewhere:</p>
  
  <pre><code>Severity    Code    Description Project File    Line    Suppression State
  Error   MSB4018 The "ResolveBlazorRuntimeDependencies" task failed unexpectedly.
  System.InvalidOperationException: Multiple assemblies found with the same assembly name 'Microsoft.CodeAnalysis.resources':
  Microsoft.CodeAnalysis.resources
  C:\Users\NickWhymark\.nuget\packages\microsoft.codeanalysis.common\3.3.1\lib\netstandard2.0\de\Microsoft.CodeAnalysis.resources.dll
     at Microsoft.AspNetCore.Blazor.Build.ResolveBlazorRuntimeDependencies.&lt;ResolveRuntimeDependenciesCore&gt;g__CreateAssemblyLookup|17_1(IEnumerable`1 assemblyPaths)
     at Microsoft.AspNetCore.Blazor.Build.ResolveBlazorRuntimeDependencies.ResolveRuntimeDependenciesCore(String entryPoint, IEnumerable`1 applicationDependencies, IEnumerable`1 monoBclAssemblies)
     at Microsoft.AspNetCore.Blazor.Build.ResolveBlazorRuntimeDependencies.Execute()
     at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute()
     at Microsoft.Build.BackEnd.TaskBuilder.&lt;ExecuteInstantiatedTask&gt;d__26.MoveNext() Test.Blazor.Client  C:\Users\myuser\.nuget\packages\microsoft.aspnetcore.blazor.build\3.1.0-preview4.19579.2\targets\Blazor.MonoRuntime.targets 252 
  </code></pre>
  
  <p>The error appears to be in the web assembly (client) project. I can't see any duplicate Analyzers in that. However in the Server project I've noticed a duplicate of Microsoft.AspNetCore.Components.Analyzers.dll. One is coming from the .Net Core 3.1 SDK folder in Program Files, and the other is coming from .nuget/packages. Note I haven't explicitly added the nuget one, it just "appeared".</p>
  
  <p>Whilst odd, I don't think the duplicate analyzers in the server project is necessarily the cause because I created a new Blazor webassembly project and that also had the duplicates but compiled correctly.</p>
  
  <p>I've tried clean/rebuild, restarting VS, deleting bin/obj folders but the problem persists.</p>
  
  <p>Other points that may be relevant:</p>
  
  <ul>
  <li>I am using the Telerik Blazor controls </li>
  <li>I have the release version of VS2019 installed as well as the preview. Which I also upgraded to
  16.4.</li>
  </ul>
  
  <p>Any help much apreciated!</p>