/// <summary>
/// Creates a closed generic type from the a generic type definition (like <see cref="IEnumerable{T}"/>) and type arguments (like <see cref="string"/>).
/// </summary>
/// <param name="genericTypeDefinition">The generic type definition</param>
/// <param name="typeArguments">Type arguments</param>
/// <returns>The generic type.</returns>
public static TypeSyntax CreateGenericTypeFromGenericTypeDefinition(TypeSyntax genericTypeDefinition, params TypeSyntax[] typeArguments)
{
GenericNameSyntax openType = genericTypeDefinition.DescendantNodes().OfType <GenericNameSyntax>().Single();
GenericNameSyntax closedType = openType.AddTypeArgumentListArguments(typeArguments);
return(genericTypeDefinition.ReplaceNode(openType, closedType));
}