title: C# 4.0 project targeting earlier framework
body: <p>Lets suppose if I have created a <code>C# project</code> which uses <code>C# 4.0 features - optional parameter</code>. What will happen if I select <code>'.Net Framework 2.0'</code> as a target framework? Will the compiler be intelligent enough to generate IL compatible with <code>2.0</code> on its own or will the Exe give <code>runtime error</code> when deployed on a machine that has only <code>.Net framework 2.0</code>?</p>