linqexpressions.cs

var expressions = new List<Expression>();

var newExpression = Expression.New(defaultCtor);
var targetObject = Expression.Variable(typeof(object),"target");
var assignTarget = Expression.Assign(targetObject, newExpression);
var streamParam = Expression.Parameter(typeof(Stream));
var sessionParam = Expression.Parameter(typeof(DeserializerSession));

expressions.Add(assignTarget);

foreach (var r in fieldReaders)
{
    var c = Expression.Constant(r);
    var i = Expression.Invoke(c, streamParam, targetObject, sessionParam);
    expressions.Add(i);
}

var body = Expression.Block(expressions);

//TODO: how do I return targetObject from the block?

var readAllFields = Expression
    .Lambda<ObjectReader>(body, streamParam, sessionParam) //this throws as the body is Void and the delegate returns Object
    .Compile();

return readAllFields;