ProjectTo with value converters

[0x5ECF4ULT]

TL;DR: There might be a bug when AutoMapper tries to handle Bytes and Chars.

When building a REST application (not relevant) I ran into a potential bug in AutoMapper. When converting a byte[] to string without a custom converter, an exception is thrown. I googled a bit around and eventually found out that this behaviour has been removed (#1153). The workaround is to implement two converters (as written below) and upon retry I was greeted with another exception (System.InvalidOperationException: Missing map from System.Byte to System.Char. Create using Mapper.CreateMap<Byte, Char>). Well I did that and hoped it would finally work. The result is the stacktrace below.

Source/destination types

Source type (EFCore mapped model)

public partial class Agent
{
    ....
    public byte[] StagingKey { get; set; }
    ....
}

Destination type

public class AgentDto
{
    ....
    public string StagingKey { get; set; }
    ....
}

Mapping configuration

public class AgentMapper : Profile
{
    public AgentMapper()
    {
        CreateMap<Agent, AgentDto>()
            .ForMember(dest => dest.StagingKey,
                opt => opt.ConvertUsing<ByteToStringConverter, byte[]>())
            .ReverseMap()
            .ForMember(dest => dest.StagingKey,
                opt => opt.ConvertUsing<StringToByteConverter, string>());
        CreateMap<Byte, Char>();
        CreateMap<Task, TaskDto>().ReverseMap();
    }
}

class ByteToStringConverter : IValueConverter<byte[], string>
{
    public string Convert(byte[] sourceMember, ResolutionContext context) =>
        Encoding.Default.GetString(sourceMember);
}

class StringToByteConverter : IValueConverter<string, byte[]>
{
    public byte[] Convert(string sourceMember, ResolutionContext context) =>
        Encoding.Default.GetBytes(sourceMember);
}

Version: x.y.z

AutoMapper.Extensions.Microsoft.DependencyInjection: 8.1.1
AutoMapper: 10.1.1
Microsoft.EntityFrameworkCore.Sqlite: 5.0.5

Expected behavior

string/byte[] objects get converted into their couterpart (eg. string -> byte[] or the other way around).

Actual behavior

An exception is thrown (System.ArgumentException: Argument types do not match)

For brevity I have only attached the relevant part of the stacktrace.

System.ArgumentException: Argument types do not match
   at System.Linq.Expressions.Expression.Bind(MemberInfo member, Expression expression)
   at AutoMapper.QueryableExtensions.Impl.EnumerableExpressionBinder.BindEnumerableExpression(IConfigurationProvider configuration, PropertyMap propertyMap, ExpressionRequest request, ExpressionResolutionResult result, IDictionary`2 typePairCount, LetPropertyMaps letPropertyMaps)
   at AutoMapper.QueryableExtensions.Impl.EnumerableExpressionBinder.Build(IConfigurationProvider configuration, PropertyMap propertyMap, TypeMap propertyTypeMap, ExpressionRequest request, ExpressionResolutionResult result, IDictionary`2 typePairCount, LetPropertyMaps letPropertyMaps)
   at AutoMapper.QueryableExtensions.ExpressionBuilder.<>c__DisplayClass10_0.<CreateMapExpressionCore>g__CreateMemberBinding|4(PropertyExpression propertyExpression, <>c__DisplayClass10_1& )
   at AutoMapper.QueryableExtensions.ExpressionBuilder.<>c__DisplayClass10_0.<CreateMapExpressionCore>g__CreateMemberBindings|1()
   at AutoMapper.QueryableExtensions.ExpressionBuilder.CreateMapExpressionCore(ExpressionRequest request, Expression instanceParameter, IDictionary`2 typePairCount, TypeMap typeMap, LetPropertyMaps letPropertyMaps)
   at AutoMapper.QueryableExtensions.ExpressionBuilder.CreateMapExpressionCore(ExpressionRequest request, Expression instanceParameter, IDictionary`2 typePairCount, LetPropertyMaps letPropertyMaps, TypeMap& typeMap)
   at AutoMapper.QueryableExtensions.ExpressionBuilder.CreateMapExpression(ExpressionRequest request, IDictionary`2 typePairCount, LetPropertyMaps letPropertyMaps)
   at AutoMapper.QueryableExtensions.ExpressionBuilder.CreateMapExpression(ExpressionRequest request)
   at AutoMapper.Internal.LockingConcurrentDictionary`2.<>c__DisplayClass2_1.<.ctor>b__1()
   at System.Lazy`1.ViaFactory(LazyThreadSafetyMode mode)
--- End of stack trace from previous location ---
   at System.Lazy`1.CreateValue()
   at AutoMapper.Internal.LockingConcurrentDictionary`2.GetOrAdd(TKey key)
   at AutoMapper.QueryableExtensions.ExpressionBuilder.GetMapExpression(Type sourceType, Type destinationType, Object parameters, MemberInfo[] membersToExpand)
   at AutoMapper.QueryableExtensions.ProjectionExpression.ToCore(Type destinationType, Object parameters, IEnumerable`1 memberPathsToExpand)
   at AutoMapper.QueryableExtensions.ProjectionExpression.ToCore[TResult](Object parameters, IEnumerable`1 memberPathsToExpand)
   at AutoMapper.QueryableExtensions.ProjectionExpression.To[TResult](Object parameters, Expression`1[] membersToExpand)
   at AutoMapper.QueryableExtensions.Extensions.ProjectTo[TDestination](IQueryable source, IConfigurationProvider configuration, Object parameters, Expression`1[] membersToExpand)
   at AutoMapper.Mapper.ProjectTo[TDestination](IQueryable source, Object parameters, Expression`1[] membersToExpand)

Steps to reproduce

[HttpGet]
public async Task<ActionResult<IEnumerable<AgentDto>>> GetAgents()
{
    return await _mapper.ProjectTo<AgentDto>(_context.Agents).ToListAsync();
}

[lbargaoanu]

https://docs.automapper.org/en/latest/Queryable-Extensions.html#supported-mapping-options