Fix of warnings.

Author: kindermannhubert

CSharpRepl.Services/Nuget/NugetHelper.cs

@@ -3,6 +3,7 @@
 // file, You can obtain one at https://mozilla.org/MPL/2.0/.
 
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Reflection;
 using System.Runtime.Versioning;
@@ -31,7 +32,7 @@ public static RuntimeGraph GetRuntimeGraph(Action<string>? error)
         return new RuntimeGraph();
     }
 
-    public static NuGetFramework GetCurrentFramework()
+    public static bool TryGetCurrentFramework([NotNullWhen(true)] out NuGetFramework? result)
     {
         var assembly = Assembly.GetEntryAssembly();
         if (assembly is null ||
@@ -41,6 +42,13 @@ public static NuGetFramework GetCurrentFramework()
         }
 
         var targetFrameworkAttribute = assembly.GetCustomAttribute<TargetFrameworkAttribute>();
-        return NuGetFramework.Parse(targetFrameworkAttribute?.FrameworkName);
+        if (targetFrameworkAttribute is null)
+        {
+            result = null;
+            return false;
+        }
+
+        result = NuGetFramework.Parse(targetFrameworkAttribute.FrameworkName);
+        return true;
     }
 }

CSharpRepl.Services/Nuget/NugetPackageInstaller.cs

@@ -57,6 +57,7 @@ public async Task<ImmutableArray<PortableExecutableReference>> InstallAsync(
             }
 
             var nuGetProject = CreateFolderProject(targetFramework, Path.Combine(Configuration.ApplicationDirectory, "packages"));
+            var settings = ReadSettings();
             var sourceRepositoryProvider = new SourceRepositoryProvider(new PackageSourceProvider(settings), Repository.Provider.GetCoreV3());
             var packageManager = CreatePackageManager(settings, nuGetProject, sourceRepositoryProvider);
 

CSharpRepl.Services/Roslyn/MetadataResolvers/AssemblyReferenceMetadataResolver.cs

@@ -134,7 +134,7 @@ private static bool TryGetAssemblyCfgPath(string? assemblyPath, string extension
                 {
                     foreach (var assemblyGroup in runtimeLib.RuntimeAssemblyGroups)
                     {
-                        if (runtimeGraph.AreCompatible(RuntimeInformation.RuntimeIdentifier, assemblyGroup.Runtime))
+                        if (runtimeGraph.AreCompatible(RuntimeInformation.RuntimeIdentifier, assemblyGroup.Runtime ?? ""))
                         {
                             foreach (var runtimeFile in assemblyGroup.RuntimeFiles)
                             {