Remove compiler package and update sourcelink (#2498)

Author: JamesNK

Src/Directory.Build.props

@@ -3,10 +3,9 @@
     <AutofacPackageVersion>4.6.2</AutofacPackageVersion>
     <BenchmarkDotNetPackageVersion>0.10.10</BenchmarkDotNetPackageVersion>
     <FSharpCorePackageVersion>4.2.3</FSharpCorePackageVersion>
-    <MicrosoftCodeAnalysisFxCopAnalyzersPackageVersion>2.9.2</MicrosoftCodeAnalysisFxCopAnalyzersPackageVersion>
+    <MicrosoftCodeAnalysisNetAnalyzersPackageVersion>5.0.3</MicrosoftCodeAnalysisNetAnalyzersPackageVersion>
     <MicrosoftCSharpPackageVersion>4.3.0</MicrosoftCSharpPackageVersion>
-    <MicrosoftSourceLinkGitHubPackageVersion>1.0.0-beta2-19367-01</MicrosoftSourceLinkGitHubPackageVersion>
-    <MicrosoftNetCompilersToolsetPackageVersion>3.8.0</MicrosoftNetCompilersToolsetPackageVersion>
+    <MicrosoftSourceLinkGitHubPackageVersion>1.0.0</MicrosoftSourceLinkGitHubPackageVersion>
     <MicrosoftNETTestSdkPackageVersion>16.3.0</MicrosoftNETTestSdkPackageVersion>
     <MoqPackageVersion>4.8.1</MoqPackageVersion>
     <NunitPackageVersion>3.11.0</NunitPackageVersion>

Src/Newtonsoft.Json/JsonSerializer.cs

@@ -867,9 +867,7 @@ internal virtual void PopulateInternal(JsonReader reader, object target)
         [DebuggerStepThrough]
         public T? Deserialize<T>(JsonReader reader)
         {
-#pragma warning disable CS8601 // Possible null reference assignment.
-            return (T)Deserialize(reader, typeof(T));
-#pragma warning restore CS8601 // Possible null reference assignment.
+            return (T?)Deserialize(reader, typeof(T));
         }
 
         /// <summary>

Src/Newtonsoft.Json/Newtonsoft.Json.csproj

@@ -39,10 +39,8 @@
     <None Include="$(PackageIconFullPath)" Pack="true" PackagePath="\"/>
   </ItemGroup>
   <ItemGroup>
-    <PackageReference Include="Microsoft.CodeAnalysis.FxCopAnalyzers" Version="$(MicrosoftCodeAnalysisFxCopAnalyzersPackageVersion)" PrivateAssets="All" />
+    <PackageReference Include="Microsoft.CodeAnalysis.NetAnalyzers" Version="$(MicrosoftCodeAnalysisNetAnalyzersPackageVersion)" PrivateAssets="All" />
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="$(MicrosoftSourceLinkGitHubPackageVersion)" PrivateAssets="All" />
-    <!-- Compiler to support nullable in non-preview VS2019 -->
-    <PackageReference Include="Microsoft.Net.Compilers.Toolset" Version="$(MicrosoftNetCompilersToolsetPackageVersion)" PrivateAssets="All" />
   </ItemGroup>
   <PropertyGroup Condition="'$(TargetFramework)'=='net45'">
     <AssemblyTitle>Json.NET</AssemblyTitle>

Src/Newtonsoft.Json/Utilities/DictionaryWrapper.cs

@@ -492,8 +492,12 @@ void IDictionary.Add(object key, object value)
 #endif
                 else
                 {
+                    // Consider changing this code to call GenericDictionary.Remove when value is null.
+                    //
 #pragma warning disable CS8601 // Possible null reference assignment.
+#pragma warning disable CS8600 // Converting null literal or possible null value to non-nullable type.
                     GenericDictionary[(TKey)key] = (TValue)value;
+#pragma warning restore CS8600 // Converting null literal or possible null value to non-nullable type.
 #pragma warning restore CS8601 // Possible null reference assignment.
                 }
             }