private TDel WrapInstanceGenericMethod <TDel>(int typeArgCount, LambdaExpression expr)
where TDel : class
{
var tDelInvoke = typeof(TDel).GetDelegateInvokeMethod();
var innerDelegateSignature =
tDelInvoke.GetParameters().Skip(typeArgCount).Select(x => x.ParameterType).Append(
tDelInvoke.ReturnType).ToArray();
var innerDelegate = Expression.GetDelegateType(innerDelegateSignature);
var gi = Create(innerDelegate, expr.ExtractMethodInfo().GetGenericMethodDefinition());
var typeParams =
Enumerable.Range(0, typeArgCount).Select(x => Expression.Parameter(typeof(Type), "targ" + x)).ToList
();
var forwardParams = gi.InArgs.Select(Expression.Parameter).ToList();
return
(Expression.Lambda <TDel>(Expression.Invoke(Expression.Call(Expression.Constant(gi),
"GetDelegate",
null,
Expression.NewArrayInit(typeof(Type), typeParams)),
forwardParams),
typeParams.Concat(forwardParams)).Compile());
}