Allow explicit loading of field-only navigations (#24548)

Fixes #23717

src/EFCore/Internal/ManyToManyLoader.cs

@@ -10,6 +10,7 @@
 using Microsoft.EntityFrameworkCore.ChangeTracking.Internal;
 using Microsoft.EntityFrameworkCore.Diagnostics;
 using Microsoft.EntityFrameworkCore.Metadata;
+using Microsoft.EntityFrameworkCore.Metadata.Internal;
 using Microsoft.EntityFrameworkCore.Storage;
 
 namespace Microsoft.EntityFrameworkCore.Internal
@@ -156,8 +157,8 @@ private IQueryable<TEntity> Query(
                 .AsTracking()
                 .Where(BuildWhereLambda(loadProperties, new ValueBuffer(keyValues)))
                 .SelectMany(BuildSelectManyLambda(_skipNavigation))
-                    .NotQuiteInclude(BuildIncludeLambda(_skipNavigation.Inverse, loadProperties, new ValueBuffer(keyValues)))
-                    .AsQueryable();
+                .NotQuiteInclude(BuildIncludeLambda(_skipNavigation.Inverse, loadProperties, new ValueBuffer(keyValues)))
+                .AsQueryable();
         }
 
         private static Expression<Func<TEntity, IEnumerable<TSourceEntity>>> BuildIncludeLambda(
@@ -173,8 +174,7 @@ private static Expression<Func<TEntity, IEnumerable<TSourceEntity>>> BuildInclud
                     EnumerableMethods.Where.MakeGenericMethod(typeof(TSourceEntity)),
                     Expression.MakeMemberAccess(
                         entityParameter,
-                        // TODO-Nullable: This could be product bug.
-                        skipNavigation.PropertyInfo!),
+                        skipNavigation.GetIdentifyingMemberInfo()!),
                     Expression.Lambda<Func<TSourceEntity, bool>>(
                         ExpressionExtensions.BuildPredicate(keyProperties, keyValues, whereParameter),
                         whereParameter)), entityParameter);
@@ -197,8 +197,7 @@ private static Expression<Func<TSourceEntity, IEnumerable<TEntity>>> BuildSelect
             return Expression.Lambda<Func<TSourceEntity, IEnumerable<TEntity>>>(
                 Expression.MakeMemberAccess(
                     entityParameter,
-                    // TODO-Nullable: This could be product bug.
-                    navigation.PropertyInfo!),
+                    navigation.GetIdentifyingMemberInfo()!),
                 entityParameter);
         }
     }

test/EFCore.InMemory.FunctionalTests/FieldsOnlyLoadInMemoryTest.cs

@@ -0,0 +1,21 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.EntityFrameworkCore.TestUtilities;
+
+namespace Microsoft.EntityFrameworkCore
+{
+    public class FieldsOnlyLoadInMemoryTest : FieldsOnlyLoadTestBase<FieldsOnlyLoadInMemoryTest.FieldsOnlyLoadInMemoryFixture>
+    {
+        public FieldsOnlyLoadInMemoryTest(FieldsOnlyLoadInMemoryFixture fixture)
+            : base(fixture)
+        {
+        }
+
+        public class FieldsOnlyLoadInMemoryFixture : FieldsOnlyLoadFixtureBase
+        {
+            protected override ITestStoreFactory TestStoreFactory
+                => InMemoryTestStoreFactory.Instance;
+        }
+    }
+}

test/EFCore.InMemory.FunctionalTests/ManyToManyFieldsLoadInMemoryTest.cs

@@ -0,0 +1,22 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.EntityFrameworkCore.TestUtilities;
+
+namespace Microsoft.EntityFrameworkCore
+{
+    public class ManyToManyFieldsLoadInMemoryTest : ManyToManyFieldsLoadTestBase<
+        ManyToManyFieldsLoadInMemoryTest.ManyToManyFieldsLoadInMemoryFixture>
+    {
+        public ManyToManyFieldsLoadInMemoryTest(ManyToManyFieldsLoadInMemoryFixture fixture)
+            : base(fixture)
+        {
+        }
+
+        public class ManyToManyFieldsLoadInMemoryFixture : ManyToManyFieldsLoadFixtureBase
+        {
+            protected override ITestStoreFactory TestStoreFactory
+                => InMemoryTestStoreFactory.Instance;
+        }
+    }
+}