Allowing Lambda Expressions with Statement Bodies Describing Iterators to be Converted to Expression Trees

[AdamSobieski]

Building on issue #3093, I would like to open an issue for discussing allowing lambda expressions with statement bodies describing iterators to be able to be converted to expression trees in C#.

Expression<Func<IEnumerable<int>>> expr = () =>
{
    for (int index = 0; index < 100; ++index)
    {
        yield return index;
    }
};

It would be quite useful if the System.Linq.Expressions expression tree model could represent the iterator pattern and if the Compile() method could, at runtime, generate iterators.

Pertinent to this issue are CS0834 (a lambda expression with a statement body cannot be converted to an expression tree) and CS1621 (the yield statement cannot be used inside an anonymous method or lambda expression).

[Joe4evr]

This falls under #158.