Don't resolve collections for not registered types when IServiceProviderIsService is used - GH-391

src/Lamar.Testing/IoC/Acceptance/IServiceProviderIsService_implementation.cs

@@ -37,6 +37,27 @@ public void fix_for_368_auto_resolve_enumerable_concretes_and_generics()
         container.IsService(typeof(IGenericService1<ConcreteClass>)).ShouldBeTrue();
     }
 
+    [Fact]
+    public void fix_for_391_dont_resolve_collections_with_not_registered_type()
+    {
+        var containerWithNoRegistrations = Container.Empty();
+
+        containerWithNoRegistrations.IsService(typeof(IEnumerable<ConcreteClass>)).ShouldBeFalse();
+        containerWithNoRegistrations.IsService(typeof(IReadOnlyCollection<ConcreteClass>)).ShouldBeFalse();
+        containerWithNoRegistrations.IsService(typeof(IList<ConcreteClass>)).ShouldBeFalse();
+        containerWithNoRegistrations.IsService(typeof(List<ConcreteClass>)).ShouldBeFalse();
+
+        var containerWithRegistrations = Container.For(services =>
+                                                      {
+                                                          services.ForConcreteType<ConcreteClass>();
+                                                      });
+
+        containerWithRegistrations.IsService(typeof(IEnumerable<ConcreteClass>)).ShouldBeTrue();
+        containerWithRegistrations.IsService(typeof(IReadOnlyCollection<ConcreteClass>)).ShouldBeTrue();
+        containerWithRegistrations.IsService(typeof(IList<ConcreteClass>)).ShouldBeTrue();
+        containerWithRegistrations.IsService(typeof(List<ConcreteClass>)).ShouldBeTrue();
+    }
+
     public interface IService
     {
     }

src/Lamar/ServiceGraph.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections;
 using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
@@ -483,14 +484,28 @@ internal ServiceFamily TryToCreateMissingFamilyWithNetCoreRules(Type serviceType
             return new ServiceFamily(serviceType, DecoratorPolicies);
         }
 
+        Type serviceTypeToLookFor = getServiceTypeThatTakesCollectionsIntoAccount(serviceType);
+
         var found = FamilyPolicies.Where(x => x is not ConcreteFamilyPolicy)
-            .FirstValue(x => x.Build(serviceType, this));
+            .FirstValue(x => x.Build(serviceTypeToLookFor, this));
 
         _lookingFor.Remove(serviceType);
 
         return found;
     }
 
+    private Type getServiceTypeThatTakesCollectionsIntoAccount(Type serviceType)
+    {
+        if (!typeof(IEnumerable).IsAssignableFrom(serviceType) || serviceType.GetGenericArguments().Length != 1) 
+            return serviceType;
+
+        Type type = serviceType.GetGenericArguments().Single();
+
+        bool isTypeRegistered = _services.Any(descriptor => descriptor.ServiceType == type);
+
+        return isTypeRegistered ? serviceType : type;
+    }
+
     internal void ClearPlanning()
     {
         _chain.Clear();