C# coercion operator?

Question

I got this test:

[Fact]
public void EverythingIsMappedJustFine(){
  new AutoMapperTask().Execute();
  Mapper.AssertConfigurationIsValid();
}

It throws a bit strange exception:

Test 'Unit.Web.Bootstrap.AutoMapperFacts.EverythingIsMappedJustFine' failed:
System.InvalidOperationException : No coercion operator is defined
between types 'System.Void' and 'System.Object'.
at System.Linq.Expressions.Expression.GetUserDefinedCoercionOrThrow(ExpressionType coercionType, Expression expression, Type convertToType)
...
at AutoMapper.DelegateFactory.CreateGet(MethodInfo method)

Unfortunately - I couldn't reproduce this on smaller scale and can't figure out what exactly is going on.

What is coercion operator?

---

This might be useful. But I'm failing to extract and dumb down necessary information bits.

Answer 1

I still don't know what exactly is coercion operator, but at least - I solved my problem found reason.

After some automapper debugging was able to reproduce problem:

namespace mappertest
{
    using AutoMapper;
    using NUnit.Framework;

    [TestFixture]
    public class FooFacts
    {
        [Test]
        public void MapToFizz()
        {
            Mapper.Initialize(c => c.AddProfile(new FooProfile()));

            var foo = new Foo { Bar = "BarValue" };
            var fooModel = Mapper.Map<Foo, FooModel>(foo);

            Assert.AreEqual("BarValue", fooModel.Bar);
        }
    }

    public class FooProfile : Profile
    {
        protected override void Configure()
        {
            CreateMap<Foo, FooModel>();
        }
    }

    public class Foo
    {
        public string Bar { get; set; }
        public void Fizz() { }
    }

    public class FooModel
    {
        public string Bar { get; set; }
        public FizzModel Fizz { get; set; }
    }

    public class FizzModel { }
}

Quite simple as it turns out - source has method which is named just like destination property.