public async void TestRoslynCompilationWithAnalyzers()
{
    Compilation compilation = GetSimpleCompilation();
    CompilationWithAnalyzers compilationWithAnalyzers = GetAnalyzerAwareCompilation(compilation);

    ImmutableArray<Diagnostic> diagnosticResults = await compilationWithAnalyzers.GetAllDiagnosticsAsync();
    if (diagnosticResults.Length == 0)
    {
        ImmutableArray<Diagnostic> diagnostics = Compile(compilationWithAnalyzers.Compilation);
        ShowDiagnostics(diagnostics);
    }
    else
    {
        ShowDiagnostics(diagnosticResults);
    }
}