I am experimenting with .NET Code Contracts. The following code runs just fine when runtime contract checking is turned off, but fails when runtime contract checking is turned on:
using System.Collections.Generic;
using System.Diagnostics.Contracts;
namespace ConsoleApplication1
{
public class Item<T> where T : class { }
public class FooItem : Item<FooItem> { }
[ContractClass(typeof(ITaskContract<>))]
public interface ITask<T> where T : Item<T>
{
void Execute(IEnumerable<T> items);
}
[ContractClassFor(typeof(ITask<>))]
internal abstract class ITaskContract<T> : ITask<T> where T : Item<T>
{
void ITask<T>.Execute(IEnumerable<T> items)
{
Contract.Requires(items != null);
Contract.Requires(Contract.ForAll(items, x => x != null));
}
}
public class FooTask : ITask<FooItem>
{
public void Execute(IEnumerable<FooItem> items) { }
}
class Program
{
static void Main(string[] args)
{
new FooTask();
}
}
}
The error I get when running this code is not a contract violation. Rather, it looks like the rewriter is somehow generating a corrupted binary:
Unhandled Exception: System.BadImageFormatException: An attempt was made to load a program with an incorrect format. (Exception from HRESULT: 0x8007000B) at ConsoleApplication1.Program.Main(String[] args)
The error goes away if I remove the following line:
Contract.Requires(Contract.ForAll(items, x => x != null));
Am I doing something wrong, or is this a bug in the binary rewriter? What can I do about it?