Build runnable .NET Core Console App using Roslyn

[DanTsk]

Version Used:
3.0.100-preview6-012264

I am trying to perform compilation to an exe file using Roslyn.
I have used this code to a source for compilation.

namespace Compiler
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello");
        }
    }
}

And code of my compiler.

namespace Compiler
{
    public class Compiler
    {
        private CSharpCompilation _compilation;

        public Compiler(string assamblyName, string[] sources) {
            var syntaxTrees = ParseSyntaxTrees(sources);

            _compilation = CSharpCompilation.Create(assamblyName, syntaxTrees, GetMetadataReference(), GetCompilationOptions());
        }

        public EmitResult Emit(string filePath)
        {
            return _compilation.Emit(filePath);
        }

        private IEnumerable<SyntaxTree> ParseSyntaxTrees(string[] sources)
        {
            return sources.Select(source => CSharpSyntaxTree.ParseText(source));
        }

        public IEnumerable<MetadataReference> GetMetadataReference()
        {
            var assemblyPath = Path.GetDirectoryName(typeof(object).Assembly.Location);

            Console.WriteLine(assemblyPath);

            return new[] {
                MetadataReference.CreateFromFile(Path.Combine(assemblyPath, "System.Private.CoreLib.dll")),
                MetadataReference.CreateFromFile(Path.Combine(assemblyPath, "System.Console.dll")),
                MetadataReference.CreateFromFile(Path.Combine(assemblyPath, "System.Runtime.dll")),
            };
        }

        private CSharpCompilationOptions GetCompilationOptions()
        {
            return new CSharpCompilationOptions(OutputKind.ConsoleApplication)
                    .WithOverflowChecks(true)
                    .WithOptimizationLevel(OptimizationLevel.Debug);
        }
    }
}

After generation of exe file in the file system (for experiment) I placed that exe to Microsoft.NETCore.App folder with all dlls, to confirm that it works.

Running generated exe file:
Expected Behavior:

Hello

Actual Behavior:
For: 3.0.100-preview6-012264

Unhandled Exception: System.TypeLoadException: Could not load type 'System.Object' from assembly 'System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e' because the parent does not exist.

I really need help with it.
Thanks a lot!

[DanTsk]

And one more small question is there ability to build single executable file without referencing dlls? Like in .NET Core 3.0 CLI PublishSingleFile=true

[agocke]

@DanTsk I believe it's considered unsupported by .NET Core to compile directly against System.Private.CoreLib.dll. In general, it will probably be quite difficult to compile an application without using the dotnet tool and MSBuild, as you will have to effectively replicate all the logic that goes into picking the appropriate reference assemblies, then generating the right executing environment for the .NET Core shared loader.

[DanTsk]

@agocke Thanks for pointing, looks like dotnet tool perfectly solves my needs.

[agyen]

@DanTsk please how did the dotnet tool helped you I'm having the same problem. Thanks