Generic type constraint resolution doesn't see arrays as IEnumerable<>

[alansingfield]

Can you help please?

I've created a service with a generic constraint for IEnumerable<> on it - it works as expected with a List<T> but not T[]

public interface IMyThing<T> { }
public interface IMyThing<T, TValue> : IMyThing<T>
    where T : IEnumerable<TValue> { }

public class MyThing<T, TValue> : IMyThing<T, TValue>
    where T : IEnumerable<TValue> { }

var container = new Container();
container.Register(typeof(IMyThing<>), typeof(MyThing<,>), Reuse.ScopedOrSingleton);

// Works - constraint of IEnumerable<TValue> brings int from List<int> into the 2nd generic parameter.
container.Resolve<IMyThing<List<int>>>().ShouldBeOfType<MyThing<List<int>, int>>();

// Works - type is compliant with the generic constraints - would not compile otherwise.
var q = new MyThing<int[], int>();

// Fails when we try to resolve it through the container
container.Resolve<IMyThing<int[]>>().ShouldBeOfType<MyThing<int[], int>>();

Full exception is:

 ArrayDoesntMatch
   Duration: 48 ms

  Message: 
    Test method GenericConstraintResolutionTests2.ArrayDoesntMatch threw exception: 
    DryIoc.ContainerException: code: Error.NoMatchedGenericParamConstraints;
    message: Open-generic service does not match with registered open-generic implementation constraints Sqleze.Tests.GenericConstraintResolutionTests2.MyThing<,> when resolving: resolution root Sqleze.Tests.GenericConstraintResolutionTests2+IMyThing`1[System.Int32[]]
      from container without scope. ---> System.ArgumentException: GenericArguments[0], 'System.Int32[]', on 'Sqleze.Tests.GenericConstraintResolutionTests2+MyThing`2[T,TValue]' violates the constraint of type 'T'. ---> System.TypeLoadException: GenericArguments[0], 'System.Int32[]', on 'Sqleze.Tests.GenericConstraintResolutionTests2+IMyThing`2[T,TValue]' violates the constraint of type parameter 'T'.

  Stack Trace: 
    RuntimeTypeHandle.Instantiate(Type[] inst)
    RuntimeType.MakeGenericType(Type[] instantiation)
    --- End of inner exception stack trace ---
    RuntimeType.ValidateGenericArguments(MemberInfo definition, RuntimeType[] genericArguments, Exception e)
    RuntimeType.MakeGenericType(Type[] instantiation)
    <>c.<GetGeneratedFactoryOrDefault>b__16_0(Type t, Type[] a) line 11598
    ReflectionTools.TryCloseGenericTypeOrMethod[T](T openGenericTypeOrMethod, Type[] typeArgs, Func`3 closeGeneric, Boolean throwCondition, Int32 error, Request r) line 14613
    --- End of inner exception stack trace ---
    ReflectionTools.TryCloseGenericTypeOrMethod[T](T openGenericTypeOrMethod, Type[] typeArgs, Func`3 closeGeneric, Boolean throwCondition, Int32 error, Request r) line 14618
    WithAllDetails.GetGeneratedFactoryOrDefault(Request request, Boolean ifErrorReturnDefault) line 11596
    IContainer.ResolveFactory(Request request) line 902
    Container.ResolveAndCache(Int32 serviceTypeHash, Type serviceType, IfUnresolved ifUnresolved) line 398
    IResolver.Resolve(Type serviceType, IfUnresolved ifUnresolved) line 386
    Resolver.Resolve[TService](IResolver resolver, IfUnresolved ifUnresolved) line 8433
    GenericConstraintResolutionTests2.ArrayDoesntMatch() line 47

[dadhi]

@alansingfield Interesting finding. Thanks. I will check how to fix it.

[alansingfield]

Thanks very much!

Will this be backported into v5 or is this a v6-only fix?

[dadhi]

I will backport.

[dadhi]

@alansingfield DryIoc v5.3.1 with the fix is out on nuget.

[alansingfield]

Maksim, I've updated to 5.3.1 and all my tests now pass. Thanks again for your help.