NullReferenceException on Unregister

[eocron]

Using unregister on keyed registrations result in NRE across all Resolve methods:
Version: all versions (tested on 2.* and 4.7.*)
Actual:

    [TestMethod]
    public void Repro()
    {
        var implementationType1 = typeof(A);
        var implementationType2 = typeof(B);
        var interfaceType       = typeof(ITargetInterface);
        var container           = new Container();
        container.Register(interfaceType, implementationType1, serviceKey: "foo");
        container.Register(interfaceType, implementationType2, serviceKey: "bar");

        container.Unregister(interfaceType, serviceKey:"foo");

        Assert.ThrowsException<ContainerException>(()=> container.Resolve(interfaceType, "foo")); //<---throws NRE
        container.Resolve(interfaceType, "foo", IfUnresolved.ReturnDefault); //<---throws NRE
        container.ResolveMany(interfaceType, ResolveManyBehavior.AsFixedArray);//<---throws NRE
    }

Expected:
Resolve with key with optional -> return default
Resolve with key - > throws ContainerException
ResolveMany for interface -> returns single registered service

PS:
Also throws on container.ClearCache(interfaceType);

[dadhi]

thanks, will look.

[dadhi]

The version v4.7.5 with the fix is out

[eocron]

Thank you!