How do I change a field type using FieldTypeDeclaration with Roslyn ?

See more:

C#

compiler

code-generation

I am using the visual studio project type - Stand-Alone Code Analysis Tool. I am using the following code but the ToString() is showing an unexpected result.

static void Main(string[] args)
        {
            var classDoc = @"public class SomeClass{
                    private SomeOtherClass someOtherClass;
                }";
            
            SyntaxTree classTree=SyntaxFactory.ParseSyntaxTree(classDoc);
            var classDecl = (ClassDeclarationSyntax)classTree.GetRoot().DescendantNodes().First(d => d is ClassDeclarationSyntax);
            var field = classDecl.Members.OfType<FieldDeclarationSyntax>().First();
            var fieldType = field.Declaration.Type;
            var newFieldType = SyntaxFactory.ParseName("System.Windows.Forms.UserControl");
            var newField=field.ReplaceNode(fieldType, newFieldType);
            var newFieldStr = newField.ToString();
        }

The newFieldStr is "private System.Windows.Forms.UserControlsomeOtherClass;"

Please advise how I can get the expected result.

Many thanks

Tony