Compilation errors when compiling project

I am trying to write a code that will test if any method has ExecuteReader without corresponding Close reader - basic test to play with, just checks if ExecuteReader and Close are in the same block.

This basic test was easy to implement and perform with Roslyn on hard-coded string with class code. However, when I try to open a solution programmaticaly and compile a project or document I get a lot of errors, here is the excerpt:

error CS0246: The type or namespace name 'Roslyn' could not be found (are you missing a using directive or an assembly reference?)
error CS0234: The type or namespace name 'Data' does not exist in the namespace 'System' (are you missing an assembly reference?)
error CS0246: The type or namespace name 'InvocationExpressionSyntax' could not be found (are you missing a using directive or an assembly reference?)

Here is the code:

            IWorkspace workspace = Workspace.LoadSolution(@"d:\test\test.sln");            ISolution solution = workspace.CurrentSolution;            foreach (IProject project in solution.Projects)            {                    var compilation = project.GetCompilation(); // tried with .AddReferences(project.MetadataReferences); also                    foreach (var diagnostic in compilation.GetDiagnostics())                    {                        diagnostic.ToString();                        Console.WriteLine(diagnostic.Info);                    }

I don't know if it matters, my test application is Roslyn Console Application.